Tech Blog

Solar Concentrator

2011-10-15T10:39:00.002-07:00

A few months ago I got into my car, and it was really hot. (over 100 degrees, I was really interested so I checked it with a thermometer)
This inspired me to build a solar oven, I mean, if my car can get that hot, just imagine if heat was actually the goal.
I built this http://www.instructables.com/id/CERC-Green-Solar-Oven/, which worked incredibly well (325 degrees F) but I feel it's severely limited by the use of tinfoil as a reflective surface.

I decided CDs would be a perfect substitute, they are more reflective, and I happen to have tons of them lying around. But my goal had never really been to create a solar oven, just to create heat from sunlight. So instead of improving my solar oven, I decided to build a parabolic solar concentrator.

Step 1Materials

-Cardboard
Corrugated is harder to cut, thin cardboard will make it more difficult to attach the mirrors*
(I used a thin corrugated cardboard)

-Tape or Glue
Tape will partially cover parts of the mirrors, cutting down on the actual light reflected, but it allows for the mirrors to be more easily removed and adjusted

-CDs

-Protractor
-Ruler
-Pen/Pencil/Marker
-Scissors
-Box cutter/X-Acto Knife

*The mirrors are actually just pieces of the CDs, but it's easier to refer to them like this

A Simple Solar Charging Station

2011-10-15T10:39:00.000-07:00

Hi, my name is Corwin and this instructable will be a guide for the process I used to build six solar powered charging stations as part of my Eagle Scout project for Boy Scouts. My main goal when I designed these stations was to make it easy to replicate and buy parts for. Please leave comments down below if you find better deals on parts or have a better way of doing something. I'll be glad to hear your input. So, let's begin with a parts list and cost estimate...

Step 1Parts List

So, obviously I tried to make this as cheap as possible since I needed to make six of them. Again, if you find better prices or have a cheaper way to make it, please share so everyone can benefit.

Electrical Components
6 - 10 Watt Solar Panel - $40 each from Amazon -Link -
6 - 3 Amp Charging Regulator - $10.50 each from Amazon -Link -
6 - 12 Volt 7 Amp Hour Sealed Lead Acid Battery - $17.37 each from eBay -Link -
12 - Inline Fuse Holders - $1.98 each from Amazon -Link -
3 - 5 Amp Fuses - $1.98 for 5 pack from Amazon -Link -
1 - Assorted Heat Shrink Tubing -$10 from Amazon -Link -
6 - Three Way Car Lighter Socket Splitter with USB port - $1.49 each from Amazon -Link -
12 - Mini USB Car Charger Adapter - $2.39 each from Amazon -Link -
1 - Assorted Spade / Ring Connectors - (Free) Already had
1 - Assorted Wire - (Free) Already had

Electrical Components Subtotal - $484.54

Body Components - All Purchased from Browne's Lumber
2 - 1/2 inch sheets AC Plywood 8ft*4ft - $25 each
3 - 4x4 Treated Post 12ft - $15 each
3 - 1lb Box Assorted Outdoor Screws - $12 each
12 - 1/4" x 6" Hex Bolt - $.79 each
24 - 1/4" x 1 1/2" Hex Bolt - $.22 each
36 - 1/4" Locking Nut - .14 each
2 - Metal Plumbers Strap - $3 per roll
1 - Ladybug Red Flat Outdoor House Paint - $15 per quart
1 - Box Assorted Screws - (Free) Already had
6 - Quikcrete - $3 per 60lb Bag
6 - Hinge Sets - $3.50 per set of 2
6 - Black Handles - $.75 each

Body Components Subtotal - $194.30

Grand Total - $678.84 for six or $113.14 each

Please note that I live on San Juan Island in the Pacific Northwest of USA. Items bought here tend to cost more than if they were bought on the mainland, so it is entirely possible to build this cheaper.

Solar Charging System

2011-10-15T10:38:00.002-07:00

Here is my Solar Charging System and how I made it. What I didnt purchase, I recycled the parts from other things I already had to make it. I will show you each part of the setup and explain its purpose.

I probably dont have to explain the purpose of the solar panel, but thats where the electricity comes from. I am not sure about this, but I heard that one of the newest types of solar panels out there is the monocrystalline. I like it very much because it is small and it produces a lot of power. It may look big in the picture, but it is actually the exact same size as a 8x11 piece of printer paper.

Step 1The Solar Panel Mount and Wiring

Here is the mount that I made for my panel, it actually came from an old TV dish so I took it off and re-used it for this project

Also in the other picture is my connection to the solar panel using a waterproof connector. Inside the red box is simply where I had to make other connections to the wire going into my room. The grey wire you see is meant to be used underground as it has 2 insulating layers on it. Also in the other picture, is the pole the panel is mounted on which is about 6 1/2 feet tall.

Solar kiln

2011-10-15T10:38:00.000-07:00

First, kudos to Dr. Brian Bond, students, and staff at Virginia Tech (VT) Department of Wood Science and Forest Products for developing a solar kiln and providing the well-written plans at:

http://woodscience.vt.edu/about/extension/vtsolar_kiln/

I, of course, modified the VT plans. The solar kiln is basically a box with a greenhouse roof that generates hot air with a internal solar collector. The hot air is blown through the wood with two (2) fans. A load of wood should take approximately one (1) month to dry.

The wood is being dried to build an 18 foot Grand Banks dory which will used to haul picnic supplies and picnic princesses to islands offf the coast of Maine. Google the Maine Island Trail Association to get a sense of the place. Building a kiln before building the boat in order to haul picnic supplies is my typical, over-zealous approach.

Please vote for this project so I can afford the solar panel to make it completely solar. I have already burnt-up a cheap-bottom box fan.

List of materials:
Enough wood to build structure - I used a combination of new and salvaged materials so don't have a list; the longer pieces and treated lumber were store bought
plywood - 3/4 inch thick, exterior grade, 2 sheets
Polygal and brackets - 10 ft x 6 ft piece; cut in half
flashing - aluminum
styrofoam insulation - 2 in thick, 2 sheets
Reflectix bubble wrap insulation
DC fans - 2, 16 inch with ring frame
GRK screws - exterior grade; various lengths
paint - green for solar collector
oven thermometer

Step 1Building the base or floor

The first question when building anything is where are you going to position it. A solar structure needs as much direct sun as possible and your neighbor may not be so keen on you cutting down their trees, even for a "green" project. I also positioned it uphill and adjacent to our workshop/garage to allow future duct work from the kiln to heat the workshop when not drying wood or other items. The position is a compromise between these functions.

The "foundation" is limestone blocks on the uphill side and a treated 4 inch by 6 inch posts on the downhill side. I set the floor level so that future duct work would intersect the adjacent workshop without hitting any wall supports.

Also my relatives on Fogo Island off the north coast of Newfoundland, had a sport of moving houses. Refer to the excellent book titled "Tilting - house launching, slide hauling, potato trenching, and other tales from a Newfoundland fishing village" by Robert Mellin for more information on this "sport. " I constructed the kiln so that it could be moved, if needed.

The next question is size. The VT plans use a base with dimensions of 160 inch by 78 inch but I reduced the dimensions to 144inches by 48 inches or 12 feet by 4 feet. I choose these dimensions to reduce building costs and the roof panels have a combined width of 12 feet and a plywood sheet is 4 feet wide.

The base is constructed of 4 inch by 6 inch treated lumber cut to a length of 11 feet 9 inches. All wood near the ground is treated lumber due to termite issues in our area. I used 2 inch by 6 inch by 4 feet long treated boards and screwed them the ends of the 11 feet 9 inches timbers to create a 12 foot by 4 foot box. Measure twice and cut once is the old carpentry policy.

Within this box, I installed cross-members. The 2 inch by 6 inch boards are connected with Simpson Strong-Tie connectors using Simpson nails (http://www.strongtie.com/). It won't be to building code without the Simpson nails. (A neighbor's contractor had to remove and replace all the wrong nails on a project of theirs; the weight of the structure is borne by these nails.) I also used leftover 4 inch by 6 inch material and attached with galvanized lag screws. I counter-sunk the lag screws so that siding could be placed over the screws.

Cheap solar hot tub/spa/pool heater

2011-10-15T10:37:00.001-07:00

This instructable covers the solar heater I made from parts available at the local hardware store (or salvage) for cheap. I have yet to do true empirical measurements on its output/efficiency, but it will raise the temp of my hot tub (~460gal) from 70 to 80 in two sunny days, and keeps it in the 90s during the summer without using the tub's heating element. This allows me to keep it warm and only use the electrical element to boost the temp when I want to jump in (saves quite a bit of $$ on electrical bills), after which this will keep the temp up in the 100s for a day or two on its own. This is the result of a few experimental panels, and the finished product turned out to be about the easiest of them all to do. A more refined version with fewer connections could be made if properly planned out.

It can be built in an afternoon, possibly just a couple hours if you have the parts ready to go. The longest wait time is for paint and sealant to dry/cure.

*Trying to find more of the pics I took while building this, taken over the course of about a year (hence the new look of the wood at the start, and OLD/weathered look at the end)

** Evidently the photo tagging thing likes to move my tags up from where I put them.... working on getting it fixed, for now just imagine them a good bit lower than where they are

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Step 1Parts and Tools

The bulk of the cost was the pump, which could be obviated if you plumb this in directly to your pool/spa pump, though that makes it harder to power independent of the spa. Make sure your pump is rated with enough head to pump the water up to the panel with enough left over to overcome the head loss of all the piping. At first I looked at solar powered fountain pumps, but couldn't find any in my price range with enough head to work. I ended up with a 320gph pond pump* with ~10' head. I am mounting mine on the roof over the hot tub, about a 7' rise, so the 10' rating is needed (and gives it a good flow rate). Properly sealed, once the water is up to the panel the siphon effect should reduce the head back to just the loss from the flow through the pipes themselves, but the water still has to get up there first. You want the pump to be able to do this on its own without priming or other assistance because the panel will eventually drain, and manually priming it to get it going again sucks, and letting it sit in full sun without water to cool it off can soften or even melt some parts.

*WARNING! (see my more detailed warning at the end of the i'ble. POND PUMPS ARE NOT RATED FOR THIS USE! YOU COULD ELECTROCUTE YOURSELF USING ONE! PLEASE USE COMMON SENSE AND GET A PUMP RATED FOR POOL/SPA USE TO BE SAFE!!!!! Continue strictly at your own risk (think: submerging the end of a LIVE 110V (220v?) power cord in a tub of water and jumping in).

Parts: 6' galvanized roofing tin panel, 2@ 8' 2x3 or 2x4, 12 wood screws (long enough to hold the boards together, so ~2.5" or be prepared to drill countersinks for shorter ones), 1" Galvanized roofing nails or corrosion resistant screws and washers (I used hardy-backer screws left over from a tiling project, with galvanized washers) , High-Heat Flat Black Rustoleum (aka Grill or engineblock paint), 150' 1/2" black irrigation line, Pump, Foam insulation board or another set of 2x3's and some "Great Stuff" type spray foam insulation (or similar 2part expanding foam), 6' Clear Corrugated panel (poly carb or pvc, probably have to buy an 8' piece and cut it, poly carb is probably preferable but much more $$. Could even go with glass if you can get it), 4x corrugated to flat insulator foam things, wire/string, silicone caulk, metal foil tape.

Tools: Drill, 1" bit, smaller pilot bits, hammer, screwdriver (or bit), caulk gun, saw, snips, measuring tape.

Independant (non-grid-intertie) solar electric system

2011-10-15T10:36:00.002-07:00

******Shameless Self-Promotion****** Before we get started, let me point out that this instructable is in the Green Living and Technology Contest. If you like what you see here, please vote for it. While your at it, vote for my other contest entry too: http://www.instructables.com/id/Not-your-average-save-energy-advice
Thank you
**End Digression... On to the Good Stuff**

Most solar systems installed on houses are hooked up to a special electric meter which can both draw on the grid and feed back into it - which makes the meter run backward.

That is pretty cool!

However, these systems generally run from around $25,000 to $50,000 and take anywhere from 10 to 20 years to make up for their up front cost in reduced utility bills.

My solar photovoltic system is independent of the utility company. It cost me about $400 (unless you happen to live in an RV, boat, or cabin, it will cost you just a little bit more)

I still use traditional electricity for some things, so I still get a bill each month, but it reduced my electric bill by almost $15 a month, which means it will pay for itself in a little over two years.

The first step for any type of solar system is to find ways to dramatically reduce the power you use in the first place.

My previous instructable is a great place to start: http://www.instructables.com/id/Not-your-average-save-energy-advice

These are steps you should be thinking about doing anyway, but it becomes all the more important when doing a solar electric project.

This is because solar systems (whether grid-intertie or not) are priced by the kilowatt. The fewer you need, the less your system costs, and the sooner it pays for itself.

Poor Man's Radio Telescope

2011-10-15T10:35:00.001-07:00

A way to peer into the radiosky using little more then junk found on the side of the road.

Remembering back to my 10th birthday. I recall receiving a book on outer space. I believe it was published by National Geographic. This was by far my most prized book in my somewhat limited collection of the time.

In it there was a rough outline of a radio telescope. This diagram so intrigued me that for years in the back of my mind I dreamed of being able to play with one.

Indeed years have past, careers, children, and everyday life was by far the most important of responsibilities. Then it happened. I spotted a 10 foot satellite dish in someone's trash.. I quickly made off with it and all its components.

The mount was in pretty bad shape. It appears to have some serious wind damage, and the pedals of the dish are in less then what I would consider acceptable shape.

None the less I slapped it all together. In the picture you can see my stinky trashcan mount. It was good for a quick test but boy did it stink.

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Step 1An examination of the feed assembly

Here we see the feed horn and low noise amplifier. All the dish components were hauled to the curb except the actual receiver unit. The bolts holding the wave guide and the amp onto the feed horn had to be purchased. Getting this feed horn back into working order took a little bit of time. It seems that the feed horn assembly was home to a community of wasps. I never realized this before but wasps build there nests to last. It took a good bit of probing and a little 409 to clean it up nice.

This is basically the meat of the system. It takes the focused energy of the dish and downconverts it into a usable signal and then amplifys it.

How is all this powered you might ask? The voltage actually travels down the coax cable that is delivering the signal to the next stage.

The polorizing servo is basically left alone, but for those of you that are curious it's a little motor that turns the antenna inside the feedhorn for better reception.

Electronic Map

2011-10-08T04:11:00.001-07:00

This is the second lesson from a Simple Circuit Unit that I created for middle school and high school students. It is fun and involves hands-on learning. For more cool hands-on engineering projects check out Machine Science (This is where I work).

http://www.machinescience.org/catalog

Step 1Simple Circuit Games Unit 2: Electronic Map

Have you ever looked at a map and wanted a quick way to know where a particular business, subway station, or landmark is located? Electronic maps, like the one shown in Figure at Boston's Museum of Science, use lights to mark the positions of local landmarks. Each button on the panel in front of the map corresponds to a location in Eastern Massachusetts. When you press the button for a particular location, its spot on the map lights up.

In this unit, you will make your own electronic map. In Challenge 1, you will construct the map board. In Challenge 2, you will add the electronic components.

Build a simple Marx Generator

2011-10-08T04:10:00.002-07:00

Do you like the idea of tesla coils and other high voltage sparking stuff, but don't have the time, money or patience to build something that is elaborate?

Well, here's a fun 'n' simple project that can make big, fat, noisy sparks at least 2 inches long, and can be built very quickly and cheaply. It might be even more fun to use a marx generator than using a 'very complicated to build' tesla coil!

And to let you know, this "Quick & Dirty" Marx generator website helped me a lot to build this marx generator.

If you have no idea what is a marx generator, you might be saying this in your mind "What the hell is a marx generator!", read about it here on Wikipedia.

WARNING! This project generates very high pulse discharge voltages, which can seriously harm and could be potentially lethal to you and others that are careless to touch the output of the marx generator.

Electronics Wipes

2011-10-08T04:10:00.000-07:00

I've seen now that you can buy little packs of LCD Monitor and Electronics wipes at the grocery store for anywhere from $4-$7 (USD). I'm somewhat frugal and if I can make something at home that works as well or better, you can bet that's just what I'll do. For years I've been using Vinegar and Water with a microfiber cloth to clean my monitors and electronics, and they do a fantastic job and that's my preferred method. However, for my laptop I need something a little more portable and that's just not the best solution. What I'm going to show being made here is for a household size container of electronics wipes. It's easy as can be to make and can cost about $2 a container roughly.

Components:
Empty Clorox Wipes container ( Any sealable airtight container will work )
1 Roll of Viva select a size paper towels
1/2 cup white vinegar
1/2 cup distilled water
hack saw or sharp bread knife

How To Get FREE Electronic parts!

2011-10-08T04:09:00.000-07:00

I found all of that expensive looking parts for free!

Plasmana

The cost of buying electronic parts for our projects from Radio Shack or Maplin are quite expensive now days...

And most of us have a limited budget in buying stuff.

But...

If you know the secrets of how to get electronic parts for free, you could be saving your self hundreds of bucks!

Heres how...

Step 1Free samples

You probably have never notices this, but most manufactures and suppliers will give away free samples of their high quality electronic parts.

However, control your self! Don't ask for hundreds of components! No company will give you that much, just ask for a few.

Here is a list of some companies and manufactures that will give you some of their free samples...

Build a World's Smallest Electronic Shocker!

2011-10-08T04:08:00.001-07:00

his amazing little shocker is very tiny and can be hidden almost anywhere and give someone a surprise shock! It can operated by almost any 1.5v batteries!

So, on this instructable, I will show you how to make shockers that is smaller than a penny!

However, the biggest disadvantage of this shocker is, it is very hard to build, but it may be easy for experienced soldering iron user (like me) to build the shocker...

Please note that I am only 15 years old and I am not very good at grammar so if you find some parts of the instructable confusing, please let me know and I will try fix it.
And excuse me for some of those blurry and hazy picture. I cannot make them better...

New and improved version!

Build a World's Smallest Electronic Shocker! version 2.5

Disclaimer: This shocker can be dangerous, it gives out 450 shocking volts, so I am NOT responsible if you or anybody are injured or killed by the shocker, the responsibility is yours...

Step 1Get the things!!

Hardly anything is needed for this project but the tools...

"Boots" or "Polaroid" type disposable flash camera (You can use a Kodak camera, but they are harder to work with).
Some wires (I got mine from broken electronic devices).
Solder.

And the tools...

Soldering iron with a micro-tip.
Desolder pump (it makes everything so much easier, but you could probably get away with out one).
Flat-head screwdriver.
Wire strippers.
Wire cutters.
Pliers.
Tweezers or micro pliers (or your hand, but you are more than likely to get a solder burn).

Also, if you don't know how to solder,

Build a World's Smallest Electronic Shocker! version 2.5

2011-10-08T04:07:00.002-07:00

It is good to know if the tiny shocker is on or not, by adding a wonderful invention called the "LED", so you don't risk get bitten by the shocker again!

Disclaimer: This shocker can be dangerous if used improperly, it gives out about 400 to 450 volts, so I am NOT responsible if you or anybody are injured or killed by the shocker, the responsibility is yours...

Improved instructable!
I have been asked by comments and email how to attach a LED to a shocker to indicate it is on. So I then decide to make another instructable how to do that.

And, I have copied and pasted everything from my original shocker instructable onto this instructable and greatly improved the text on every step, also added more steps and replaced some pictures. I am hoping it would be less confusing to you and understand the project better so you can have an higher success in completing this project. :-)

If you do find anything confusing or an error on this instructable, please let me know and I'll fix it.

Step 1What type of disposable camera should I use?

The best disposable camera you can use for this project are the "Boots" or "Polaroid" types, because they have everything you need.
The "Kodak" type is a bit more difficult, you need to find the type that uses an LED indicator, NOT a neon bulb indicator, those types will not work. Also, the LED type cameras uses SMD resistors, so you will need to find or buy one 220 ohm and one 100 ohm resistors.
All other types of cameras like "fuji" ect. will not work because they have an different and/or more complex circuitry.

Electronic Detonator

2011-10-08T04:07:00.000-07:00

This project describes how to build a simple, safe, and reliable electronic detonator. All the parts should total under 25$, and all but one of the parts can be bought at radio shack. This detonator includes numerous safety features such as a detachable power supply, an ARM switch, and an indicator light.

What I like about this project, is that all the parts can be bought in one place, and the one part that couldnt be bought at Radio Shack had to be mail ordered anyway, so I wound up only making one trip. I include the model #'s when I could find them.

Parts:

1. Project box (As close to 3x2x1.5 as you can get, remember you need enough room to hold the components but you want a good fit for your hand)
2. A momentary push switch (Model: 275-609)
3. Toggle Switch with On/Off Label Plate (Model:275-602)
4. 5mm Green LED (Model: 276-022)
5. 1/8" Mono Panel-Mount Audio Jack (Model: 274-251) its a 3 pack see but you only need 1.
6. 1/4" mono Panel-Mount Audio Jack (Catalog #: 274-252)
7. 1/8 Mono Phone Plug (Model: 274-286)
8. 2-Conductor Standard Phone Plug (Model: 274-1544) I think thats the one I got, Its got the picture on the website that most looks like mine, however, I'm sure any 1/4" mono (even stereo but then you'd have to pay closer attention to your wiring) plug would work.
9. Soldering Iron and solder
10. 2-Conductor Intercom Wire (Model: 278-857) Im pretty sure thats the wire I bought.
11. Heavy-Duty 9V Snap Connectors (Model: 270-324) Like the other packages it has more then you need
12. 8 AA Battery Holder (Model: 270-407)
13. 8-Pack AA Enercell® Alkaline Batteries (Model: 23-874)
14. Slim Line 2" Alligator Clips (Model: 270-346)
15. Drill with assorted bits
16. Spare hookup wire (You can cut off some of the intercom wire if you need to)
17. Nichrome wire (Can either be bought on e-bay or Unitednuclear.com) make sure you don't get the wire too thick I use unitednuclear.com, but I don't know what gauge it is.
18. I'm assuming you have tools like screwdrivers and wire cutters.

DIY Electronic Drums (Drum Module Req'd)

2011-10-08T04:06:00.000-07:00

So last year I needed to keep things quiet for my housemates, and as a drummer that took a bit of restraint. I surfed around on the internet and found some great web sites after reading about a DIY drum set on Hack-a-day, and what do you know, a month later, I had a full electronic set!

This is kind of a general overview, the basic concepts are fairly simple. I looked at a lot of info out there before building my own, and I just kind of planned it as I built, it just takes a little creativity. Sorry to not include any links, just google it, I couldn't find the specific pages I used, but there is a community of people out there who do this stuff.

So an electronic drum set can run you back $600-3000+, sometimes without a module, my main reason for doing this was to save money bigtime. For comparison the cost for me was around $150-200 for all parts, then the module, so a total of at most $370, which as you drummers know is even cheaper than entry level acoustic sets! The most expensive item was the electric drum module or heart of it all which I will get to later. Heres a quick summary of my bill of major materials and costs:

-Drum pads -> 2 used toms 10" and 12" about 20$ each

-Cymbals -> plastic practice cymbals, $30 for a set

-Bass pedal/stands/mounting hardware -> came from existing acoustic set FREE
(note: I had these laying around, I would suggest being a bit creative about your solution if you dont own a drum set. I had first planned on using pvc or steel pipe, it would be much cheaper as a drum stand can run up to about 100$ for a simple studry one, Perl,Tama etc. The bass pedal might be the only thing you need to purchase, check for used hardware etc, or again, this is Instructables, your crafty people :-P).

-1/4" mono Wires (one per pad) & Electronic parts, $30-40

-Wood -> FREE (scavenged)

-Drum Module, $170 (ebay, "Alesis D4")

Basically I'm trying to convey how little money you would actually have to spend to have a working set minus the drum module. This set, after tuning the sensitivity of the pads (function of the drum module), gets about 4-5 levels of "volume" depending on the power of the hit. It's a great set for practice, and I wouldn't hesitate to play it live if I got the cash for a nice amp together...

Step 1Pads 101

So this is really the most important part of this instructable, and it's really not that complicated at all, which was my motivation to build this set in the first place. I'm going to break this step down into parts and give you the important details below:

Piezos:
These are basically buzzers that can be bought at radio shack for about 2-3$ each. I believe they produce a signal when banged around that can be picked up by a drum module, translating the signal into a MIDI voice with the appropriate volume etc proportional to the impact. These are tiny flat discs when taken out of their casing, and are usually isolated from the impact of the stick by rubber/foam etc. Each disc has 2 wires, that you hook to a female 1/4" mono jack. The simplest pad would be say 2 cd-r's with the piezo glued in between them, covered by some material that your drum stick would be in contact with. Just make sure the piezo is attached to a rigid surface if you go the "sandwich" pad route, the vibrations travel better etc etc. Once you purchase these, you must "shell" them to get the actuall ceramic/metal disc out (see pics).

Connection:
Most drum modules/pads work with 1/4" mono jacks, simple 2 conductor wires are used to link pads to module, the black wire (-) from the piezo goes to the tip of the plug, while the red wire is connected to the outer sheath. The cables I have are male ends, while the drum module and pads have female connectors. These are cheap and widely available at electronics stores as well.

My Implimentation:
I first just made the piezo circuit as a test, hooked it up to an amp, and gradually flicked the piezo while turning up the volume. Once I heard a sharp sound from the amp I knew I was in business (this means that the piezo was sending a signal when it was impacted, bumped etc. My 4 main drum pads are 2 toms that I stripped hardware from, and sliced in half (I built a jig for my tablesaw to rotate the drum while cutting, easier options exist :-P). I went with a "suspended bridge" to go across the center of the drum and hold the peizo, sandwiched in in foam, up against the drum head, (the foam just push the head up in the middle ever-so-slightly for contact). I used mesh heads, like screen door material, as the sound the head will produce is useless as the real sound comes from the drum module, plus this keeps it quiet. I wanted to do it this way to emulate the more expensive pads that allow you to use drum heads, the feel is just like a normal set!

Cymbals are much easier, get a flat disc/rigid surface, and glue/fasten the piezo right to it, hook it to a female jack, and there you go! For my hi-hat I had a practice pad laying around, I took it apart, added a cd-r with a piezo glued to it into the sandwich of foam under the drum head. Mousepad material is great for a surface if you desire to change the feel of your cymbals, or if you make flat pads, and skip the real drum look/feel. You could essentially glue 5 piezos+jacks to a board, cover them with mousepad material, and have a finger drum set, thats how easy this is!

If you look in the picture of the full set you can see inner rings in each drum, these are called RemO's and basically help to muffle vibrations. This keeps the reverberation of the drum head down so as to avoid "double-triggering" (basically 2 hits being registered when you only hit the pad once). Rigid sandwich pads probably won't suffer from this much if at all.

The object in the top of the picture of 4 items is a butane torch with a tip for soldering, which I should mentioned is involved in this project. Nothing really hard, just joining wires to wires and to the mono jacks.

USB Project :- USB Interface Board Using PIC18F4550

2011-10-07T11:31:00.001-07:00

Ever want to interface with a computer? I don't mean in the regular way either, I mean the real down and dirty strip wires and plug stuff in kind of interfacing! Yeah! No? Then this Instructable isn't for you and you should move on now.

Oh you're still here? Good! In this article I'd like to present a project where I did just that. Now I should say right up front that you can just buy these things and they're called Break Out Boards (BOB) and one will set you back anywhere from $25 to say maybe $50 or more depending on the features, or how greedy the seller is etc. My board cost me about $6 to make but I had some of the most expensive components on hand to work with. Namely the barrier terminal strips, which if you're creative you don't even really have to use.

These boards aren't much more than glorified terminal strips anyways but we'll be addressing just exactly what is going on here throughout the article. These are the features of this project:

Low port micro-ampere current draw
Reliable known output source or sink current of 24ma
Simple connection
Easy construction

OK now I know that doesn't sound like much and it really isn't but that isn't to say that this is trivial or unimportant either. I thought long and hard about the mysteries of the Parallel Port before I built mine and what this board primarily does is remove a lot of the unknowns from the interface. Unknowns such as just how much current can I draw from a Parallel Port? Go out and search I dare you to get a straight answer. Come back when you're as confused as I was and we'll talk about it.

Hook my board up and it is a cut and dried 24ma. If you draw more you're probably only out a 50 cent IC too. That alone HAS to be worth the price of admission! But wait there's more, it slices, it dices, it julians fries ... OK maybe it doesn't do those things. What it does do though is plug into a parallel port and give you convenient buffered connection points.

Like I said they sell these things commercially so it can't be that stupid. It really isn't either.

Step 1About the Parallel Port

I'm not going to try to educate anyone about the parallel port here. There are a ton of websites all over the Internet about the topic. What I would like to talk about is the parallel port and how it relates to this project though.

I know today's computers no longer come with parallel ports but that isn't necessarily such a bad thing. First off who wants to put a valuable new computer at risk experimenting on it? I know I don't! Second parallel port cards are still available that will plug into any machine with a PCI slot. These add on cards offer several advantages over a built in parallel port as well so they are worth considering if you plan on trying this project for yourself. An add on Parallel Port Card is what I use. USB to parallel port adapters are outside the scope of this project so I won't be addressing those at all. My board will likely work with those as well within the limits of the USB specification. If you don't know what that means search for USB realtime to see if it applies to you.

The advantages of an add on card include the fact that the add on board isn't built into your PC, so there is less risk of damaging the motherboard connecting to one. These cards are far cheaper than motherboards so if you break one you are out a lot less. Also, the add on boards are often more robust than many built in parallel ports are, so a port card is a bit harder to break to begin with. Now if you have an old PC hanging around and you don't care too much if you break it fooling around then using that is fine too. Old PCs can be cheaper than cheap, free even. While add on parallel ports cards are pretty cheap they're not cheaper than free.

The whole point of this project is really not to break anything at all though. The point being that while yes it is fun to play around with stuff, it is less fun to play around with stuff and break it. The hardware discussed in this project is meant to shield and protect a PC from your external tinkering. Now I cannot guarantee that you still won't break something if you try this. But I can say that if you build this project right you will be able to do a bit more than you normally can with just a plain old parallel port.

How To Manually Merge Gmail Account With Apple Mail 2.0-3.x

2011-10-07T11:30:00.003-07:00

This tutorial will instruct those with basic computer skills how to merge their Gmail account into Apple Mail 2.0-3.x in 10-15 minutes.

YOU WILL NEED:
-an Apple computer with Apple Mail 2.0-3.x
-an Internet connection
-an existing Gmail account

HOW TO CHECK IF YOU HAVE THE CORRECT VERSION OF APPLE MAIL (2.0) :

1. Open the APPLE MAIL APPLICATION .
            -The mail icon will be on your desktop. This looks like a postage stamp with an eagle on it.
            -If you cannot find Apple Mail, search for the application using the magnifying glass on the top right corner.

2. Click MAIL on top left of the computer screen.
            -A drop down menu will appear.

3. Select ABOUT MAIL from the drop down menu.

4. A pop up screen should come up stating what version of Apple Mail you have.

5. If you have Apple Mail 2.0 or any Apple Mail 3.X , then you can manually follow this tutorial.

6. Exit out of all windows.

Arduino Controlled Relay Box

2011-10-07T11:30:00.001-07:00

This project is designed to help you construct some relay boxes for controlling power from your wall socket using an arduino or microcontroller. The inspiration for writing an instructable came when I decided to build some relay boxes for my personal Garduino project. For safety concerns I started designing my own relay circuit and outlet until I came across SparkFun's article "Controlling Big, Mean Devices".

I decided to abandon my own plans mainly due to time and cost and ordered the parts from SparkFun. What follows is essentially the same information you'll find on their guide but with a few of my own notes. I hope that you find my insights helpful and it will get your project off the ground without a hitch.

Step 1Parts and Safety

The great thing about this project is that there aren't a lot of parts that you need to get started. You probably have most of the parts lying around your junk box and the rest you can order directly from SparkFun or your favorite supplier. I've made a list of parts available on my wiki. SparkFun can supply the relay and PCB and your local hardware store will have your GFCI Outlet and electrical housing.

Now a brief note about safety. Every time you work with electrical lines you may be risking your life if you don't use the right precautions. In general you should always employ a certified electrician but you can do this project on your own if you're careful. Absolutely ensure the plug is not connected to a live electrical socket when working on the relay, the outlet, or the extension cord at any point. Also, it's probably good practice to enclose any wires before testing. With that you should probably do just fine.

Solar charger

2010-10-20T09:45:00.000-07:00

Here is a solar charger circuit to charge Lead Acid or Ni-Cd batteries using solar energy. The circuit harvests solar energy to charge a 6 volt 4.5 Ah rechargeable battery for various applications. The charger has Voltage and Current regulation and Over voltage cut off facilities.

Passive Aircraft Receiver

2010-10-20T09:36:00.000-07:00

The Passive Aircraft Receiver is basically an amplified "crystal radio" designed to receive nearby AM aircraft transmissions. The "passive" design uses no oscillators or other RF circuitry capable of interfering with aircraft communications so it should be fine inside the cabin of the aircraft. Nevertheless, check the regulations before using this receiver on a commercial airliner. New security regulations probably prohibit this device on commercial flights. Do not expect to hear two-way aircraft transmissions with this receiver! It is a short-range receiver only.

The detector diode is a 1N5711, HP2835 or similar Schottky detector diode. The 10 megohm resistors provide a small diode bias current for better detector efficiency. The tuning capacitor may be any small variable with a range from about 5 pF to about 15 or 20 pF. The 0.15 uH inductor may be a molded choke or a few turns wound with a small diameter. Experiment with the coil to get the desired tuning range. The aircraft frequencies are directly above the FM band so a proper inductor will tune FM stations with the capacitor set near maximum capacity. (The FM stations will sound distorted since they are being slope detected.) Other capacitor and inductor combinations may be selected to tune other bands if desired. (Try the CB band at 27 MHz.) The LM358 dual op-amp draws under 1 ma so the battery life is quite long. A speaker amplifier may be added to drive a speaker or low-z earphone. The antenna can be a couple of inches if the receiver is near the transmitter or a couple of feet for maximum range. The selectivity is reduce as the antenna length is increased so best performance is achieved with the shortest acceptable antenna. Try increasing the 1.8 pF capacitor value when using very short antennas and decreasing it for long antennas. The receiver could be built into a small plastic box with a short antenna inside.

Signal and Tone Activated Relay Switch

2010-10-20T09:31:00.000-07:00

In the Fig.1, exist a circuit, which is a sensitive switch that corresponds in AC signals of input, for signals above 5mV. Corresponds in all the signals from 50 HZ until 3KHZ, region in which found the human voice. The RV1 is regulated so much what RL1 its in situation OFF, when the input is it has null signal. In the Fig.2, exist a band - pass filter, coordinated in the 1KHZ, which can be placed in line in the bronchus of negative feedback, in points A, B, C, making sensitive the circuit only in this frequency.

	Part List

R1-2-6=10Kohm	C1-2-3=100nF	D2=1N4001
R3=1Mohm	C4=47uF 16V	Q1=BC214L
R4=33Kohm	C5-7=10nF	IC1=LM741
R5=1Kohm	C6=20nF [10nF//10nF]	RL1=12V Relay >120ohm
R7-8=15Kohm	RV1=10Kohm TRIMMER
R9=7.5Kohm [15K//15K]	D1=1N4148

Off line UPS 600Watts Square Wave

2010-10-08T06:28:00.000-07:00

fgf

Note:
I have been using this circuit from the last 2-years sucsessfuly

Discrete Voltage Inverter

2010-09-15T06:33:00.000-07:00

Discrete Voltage Inverter

The circuit in the diagram enables a negative voltage to be derived without the use of integrated circuits. Instead, it uses five n-p-n transistors that are driven by a 1 kHz (approx) TTL clock. When the clock input is high, transistors T1 and T2 link capacitor C1 to the supply voltage, UIN, which typically is 5 V. During this process, transistor T5 conducts so that T3 and T4 are off. When the clock input is low, T5 is cut off, whereupon transistors T3 and T4 are switched on via pull-up resistor R6 and either R4 or R5.

This results in the charge on C1 being shared between this capacitor and C2 Since the +ve terminal of C2 is at ground potential, its –ve terminal must become negative w.r.t. earth. The high level at the clock input must be of the same order as the positive input voltage, UIN, otherwise T1 cannot be switched on. The clock frequency should be around 1 kHz to ensure a duty cycle ratio of 1:1. Altering the ratio results in a different level of negative output voltage, but this is always smaller than that with a ratio of 1:1.

Two-Wire Temperature Sensor

2010-09-15T06:31:00.000-07:00

Two-Wire Temperature Sensor

The Type LM35 temperature sensor from National Semiconductor is very popular for two reasons: it produces an output voltage that is directly proportional to the measured temperature in degrees Celsius, and it enables temperatures below zero to be measured. A drawback of the device is, however, that in its standard application circuit it needs to be connected to the actual measuring circuit via a three-wire link. This drawback is neatly negated by the present circuit. When the LM35 is connected as shown, a two-wire link for the measurement range of –5 °C to +40 °C becomes possible.

Actually, the circuit shown is a temperature-dependent current source, since it uses the variation of the quiescent current with changes in temperature. The values of resistors R3 and R4 are calculated to give an output voltage of 10mV °C–1. Where good accuracy is desirable or necessary, 1% resistors should be used. In this context, note that a loss resistance in the link between sensor and measuring circuit may cause a measurement error of about 1 °C for every 5 ohms of resistance. Capacitor C1 eliminates undesired interference and noise signals. At an ambient temperature of 25 °C, the circuit draws a current of about 2mA.

Mains/Fuse Failure Indicator

2010-09-15T06:23:00.000-07:00

Mains/Fuse Failure Indicator

The indicator shows when the mains is present at its output by a continuous glow of a neon bulb, La1, and when the fuse is blown by flashing of the neon bulb. When the fuse is intact, capacitor C2 acts as the series resistance for the neon bulb, so that this glows continuously. When the fuse has blow, the mains voltage across diode D1 is applied as a pulsating direct voltage to network R1-C1. Capacitor C1 charges slowly and when the voltage across it reaches 80–100 V, the neon bulb comes on. Capacitor C1 is then discharged slowly via diode D2 and the bulb.

When the voltage across it has dropped sufficiently, the bulb goes out, whereupon C1 slowly charges again. This process repeats itself, so that, provided the values of R1 and C1 are right, the bulb flashes visibly. The potential across capacitor C2 is a ramp with a peak value of 30 V (which is, of course, applied to the load). Note that the neon bulb used for this purpose must not be a type that has a built-in series resistor.

Basic Inverter circuit diagram

2010-09-05T09:38:00.000-07:00

This is the bacis of inverter circuit diagram. The circuit will convert 12V DC to 120V AC. This circuit can handle up to 1000Watts supply depends the T1, T2 and transformer used. Please see the note.

Component list:

Part	Total Qty.	Description	Substitutions
C1, C2	2	68 uf, 25 V Tantalum Capacitor
R1, R2	2	10 Ohm, 5 Watt Resistor
R3, R4	2	180 Ohm, 1 Watt Resistor
D1, D2	2	HEP 154 Silicon Diode
Q1, Q2	2	2N3055 NPN Transistor (see “Notes”)
T1	1	24V, Center Tapped Transformer (see “Notes”)
MISC	1	Wire, Case, Receptical (For Output)

Notes:

1. Q1 and Q2, as well as T1, determine how much wattage the inverter can supply. With Q1,Q2=2N3055 and T1= 15 A, the inverter can supply about 300 watts. Larger transformers and more powerful transistors can be substituted for T1, Q1 and Q2 for more power.

2. The easiest and least expensive way to get a large T1 is to re-wind an old microwave transformer. These transformers are rated at about 1KW and are perfect. Go to a local TV repair shop and dig through the dumpster until you get the largest microwave you can find. The bigger the microwave the bigger transformer. Remove the transformer, being careful not to touch the large high voltage capacitor that might still be charged. If you want, you can test the transformer, but they are usually still good. Now, remove the old 2000 V secondary, being careful not to damage the primary. Leave the primary in tact. Now, wind on 12 turns of wire, twist a loop (center tap), and wind on 12 more turns. The guage of the wire will depend on how much current you plan to have the transformer supply. Enamel covered magnet wire works great for this. Now secure the windings with tape. Thats all there is to it. Remember to use high current transistors for Q1 and Q2. The 2N3055′s in the parts list can only handle 15 amps each.

3. Remember, when operating at high wattages, this circuit draws huge amounts of current. Don’t let your battery go dead .

4. Since this project produces 120 VAC, you must include a fuse and build the project in a case.

5. You must use tantalum capacitors for C1 and C2. Regular electrolytics will overheat and explode. And yes, 68uF is the correct value. There are no substitutions.

6. This circuit can be tricky to get going. Differences in transformers, transistors, parts substitutions or anything else not on this page may cause it to not function.

SOLID STATE RELAY

2010-08-31T08:43:00.000-07:00

SOLID STATE RELAY REQUIRES ONLY 50uA DRIVE CURRENT
This circuit demands a control current that is 100 times smaller than that needed by a typical optically isolated solid state relays. It is ideal for battery-powered systems. Using a combination of a high current TRIAC and a very sensitive low current SCR, the circuit can control about 600 watts of power to load while providing full isolation and transient

Video Signal Amplifier

2009-03-13T07:16:00.001-07:00

General Description

Video cassette recorders are becoming ever so popular and as it was to be expected the market is flooding with accessories that make the use of the VCR easier and enhance its operation. The circuit that we offer to you here is a broad band amplifier which will take the video signals from your VCR and will amplify them sufficiently to drive up to 3 monitors, TV sets (provided that they can accept direct video signals), or other VCR’s for recording from one video to up to three others. It will also make possible to record from one video to two others and at the same time have a monitor connected to check what you are recording. The amplifier is also very useful if the video recorder is far from the monitor.

How it Works

The circuit uses five transistors and is a broad band amplifier with a bandwidth of 5 MHz. The signal is applied at points 1 and 2 (ground) and is taken through C1 to the first stage which is a preamplifier and is built around Q1. In the output of Q1 are DC coupled Q2,3 which amplify the signal more, and as they are DC coupled to the preamplifier there is virtually no distortion and the amplification is quite high. Finally the signal from the out put Q3 is fed to the output transistors which are Q4 & Q5. These two transistors are complementary and the signal from their common emitters is taken to the signal distribution R-C network from where it is sent to the various devices which are driven by the circuit. The circuit needs a 12 VDC power supply and it is much better if it is a stabilised one like the circuit printed elsewhere in the instructions.

Construction

First of all let us consider a few basics in building electronic circuits on a printed circuit board. The board is made of a thin insulating material clad with a thin layer of conductive copper that is shaped in such a way as to form the necessary conductors between the various components of the circuit. The use of a properly designed printed circuit board is very desirable as it speeds construction up considerably and reduces the possibility of making errors. Smart Kit boards also come pre-drilled and with the outline of the components and their identification printed on the component side to make construction easier. To protect the board during storage from oxidation and assure it gets to you in perfect condition the copper is tinned during manufacturing and covered with a special varnish that protects it from getting oxidised and also makes soldering easier. Soldering the components to the board is the only way to build your circuit and from the way you do it depends greatly your success or failure. This work is not very difficult and if you stick to a few rules you should have no problems. The soldering iron that you use must be light and its power should not exceed the 25 Watts. The tip should be fine and must be kept clean at all times. For this purpose come very handy specially made sponges that are kept wet and from time to time you can wipe the hot tip on them to remove all the residues that tend to accumulate on it. DO NOT file or sandpaper a dirty or worn out tip. If the tip cannot be cleaned, replace it. There are many different types of solder in the market and you should choose a good quality one that contains the necessary flux in its core, to assure a perfect joint every
time.

DO NOT use soldering flux apart from that which is already included in your solder. Too much flux can cause many problems and is one of the main causes of circuit malfunction. If nevertheless you have to use extra flux, as it is the case when you have to tin copper wires, clean it very thoroughly after you finish your work. In order to solder a component correctly you should do the following:
- Clean the component leads with a small piece of emery paper.
- Bend them at the correct distance from the component’s body and insert the component in its place on the board.
- You may find sometimes a component with heavier gauge leads than usual, that are too thick to enter in the holes of the p.c. board. In this case use a mini drill to enlarge the holes slightly. Do not make the holes too large as this is going to make soldering difficult afterwards.
- Take the hot iron and place its tip on the component lead while holding the end of the solder wire at the point where the lead emerges from the board. The iron tip must touch the lead slightly above the p.c. board.
- When the solder starts to melt and flow, wait till it covers evenly the area around the hole and the flux boils and gets out from underneath the solder. The whole operation should not take more than 5 seconds. Remove the iron and leave the solder to cool naturally without blowing on it or moving the component. If everything was done properly the surface of the joint must have a bright metallic finish and its edges should be smoothly ended on the component lead and the board track. If the solder looks dull, cracked, or has the shape of a blob then you have made a dry joint and you should remove the solder (with a pump, or a solder wick) and redo it.
- Take care not to overheat the tracks as it is very easy to lift them from the board and break them.
- When you are soldering a sensitive component it is good practice to hold the lead from the component side of the board with a pair
of long-nose pliers to divert any heat that could possibly damage the component.
- Make sure that you do not use more solder than it is necessary as you are running the risk of short-circuiting adjacent tracks on
the board, especially if they are very close together.
- When you finish your work cut off the excess of the component leads and clean the board thoroughly with a suitable solvent to
remove all flux residues that may still remain on it.
- The construction should not present any difficulties if you follow the circuit diagram carefully and place the components in their place as it is outlined on the component side of the p.c. board. Solder first of all the pins, then the resistors, the capacitors making sure that the electrolytic are connected correctly with respect to their polarity and finally insert the transistors in their places and solder them very carefully as overheating during soldering can destroy them. When all the components have been soldered make a careful inspection of the circuit and if you are satisfied that there are no mistakes make the following connections:
- Supply voltage at points 3 (+12 VDC) and 4 (-).
- Input signal at points 1 (signal) and 2 (common).
- Outputs 5,6,7 (signal) and 4 (common).

As it is only two of the outputs are connected initially. To enable the third you should also connect the positive leads of C7 and C9 together.

High Power 800 MHz/AMPS Cellular Phone Jammer

2009-03-13T07:12:00.000-07:00

This is an outdated project.

It is possible to build an AMPS cellular phone system jammer using commonly available parts. This will only work with the older, analog 800 MHz cellular phone system and is for reference only. The theory is to generate a signal that is in the same frequency band as the phone is operating in, but at a much higher power than the normal received phone signal. Sweeping that signal across the entire cellular phone band will jam any phone in the immediate area.

The most important part of the jammer is the initial RF signal source. Generating the RF signal is very easy today with an IC from Maxim IC. The MAX2622 is a monolithic voltage-controlled oscillator that covers the frequency range of 855 MHz to 881 MHz. Review the datasheet (151k PDF) then order a few MAX2622's from Maxim directly. The device is in a tiny little 8-pin µMAX package, so you may want to mount it on a SurfBoard from Digi-Key, part number 33108CA-ND, to make it more easy to work with. Note that you'll need to glue a copper ground plane to the bottom of the SurfBoard using a scrap piece of copper clad PC board material. Drill the ground vias as needed.

The next part of the jammer is the sweep generator circuit, this can surprisingly be built using (mostly) parts from Radio Shack. It's just a twin-tee tone generator buffered/amped by a LM1458 op-amp. This outputs the sweeping voltage that connects to the MAX2622's voltage tune pin.

You'll also need to aquire an old bag-style cellular phone (Nokia/Tandy/Uniden are best) for it's power amplifier module, usually a PF0030. This will be the intermediate power amplifier and will drive the final power amplifier. There are a few possibilities in this stage and they will be described later.

Jamming distance depends on RF output power and antenna. Doesn't work on those PCS phones (yet!)

Additional Notes

Can also be used to jam 800 MHz trunking and SMR radios (i.e. racist cops) and will do a little damage to the 900 MHz ISM band.
The third harmonic of a sweeping 800 - 828 MHz signal will jam devices operating in the 2.4 GHz ISM band. Great for taking out overzealous ISPs.

Portable GSM900 Cellular Phone Jammer

2009-03-13T07:10:00.000-07:00

Emits a carrier that sweeps the 925-960 MHz cellular tower transmitter band (handset receive band)

Circuit of RF Power Amplifier:

TV remote control Blocker

2009-03-13T07:00:00.000-07:00

Just point this small device at the TV and the remote gets jammed . The circuit is self explanatory . 555 is wired as an astable multivibrator for a frequency of nearly 38 kHz. This is the frequency at which most of the modern TVs receive the IR beam . The transistor acts as a current source supplying roughly 25mA to the infra red LEDs. To increase the range of the circuit simply decrease the value of the 180 ohm resistor to not less than 100 ohm.

It is required to adjust the 10K potentiometer while pointing the device at your TV to block the IR rays from the remote. This can be done by trial and error until the remote no longer responds.

CardBus pinout 32-bit bus defined by PCMCIA

2009-03-13T06:56:00.001-07:00

68 pin male connector at the controller

68 pin female connector at the peripherals

CardBus, the 32-bit high performance bus mastering architecture for PC Cards, was standardized by the PCMCIA in May 1996. This bus is targeted to mobile computers. PCI-like 32-bit interface operates at a power-saving 3.3 volts, and cards can include standardized power-management mechanisms. The CardBus interface allows an I/O adapter or a memory module to be added to or removed without disrupting the system"s operation. It adds high bandwidth PCI-based capabilities to the PC Card technology.

CardBus PC Cards are attached to their host system through a sturdy 68-pin connector, which is common to all PC Cards. (CardBus cards employ a shielding shroud around this connector, to enhance their signal integrity).

CardBus cards adopt the well-established PC Card form-factors. There are different types of CardBus cards (sizes are TxLxW):

Type I: 3.3mm x 85.6mm x 54.0mm
Type II: 5.0mm x 85.6mm x 54.0mm
Type III: 10.5mm x 85.6mm x 54.0mm

CardBus provides a 32-bit multiplexed address/data path, which operates at PCI local-bus speeds of up to 33 MHz, yielding a peak bandwidth of 132MB/sec. CardBus accomplishes this by adopting the synchronous burst-transfer orientation of PCI, as well as a bus protocol, which is essentially identical to that of PCI.

Pin	Name	Description
1	GND	Ground
2	CAD0	Address/Data 0
3	CAD1	Address/Data 1
4	CAD3	Address/Data 3
5	CAD5	Address/Data 5
6	CAD7	Address/Data 7
7	CCBE0#	Command/Byte Enable 0
8	CAD9	Address/Data 9
9	CAD11	Address/Data 11
10	CAD12	Address/Data 12
11	CAD14	Address/Data 14
12	CCBE1#	Command/Byte Enable 1
13	CPAR	Parity
14	CPERR#	Parity error
15	CGNT#	Grant
16	CINT#	Interrupt
17	Vcc	Vcc
18	Vpp1	Vpp1
19	CCLK	CCLK
20	CIRDY#	Initiator Ready
21	CCBE2#	Command/Byte Enable 2
22	CAD18	Address/Data 18
23	CAD20	Address/Data 20
24	CAD21	Address/Data 21
25	CAD22	Address/Data 22
26	CAD23	Address/Data 23
27	CAD24	Address/Data 24
28	CAD25	Address/Data 25
29	CAD26	Address/Data 26
30	CAD27	Address/Data 27
31	CAD29	Address/Data 29
32	RSRVD	Reserved
33	CCLKRUN#	CCLKRUN#
34	GND	Ground
35	GND	Ground
36	CCD1#	Card Detect 1
37	CAD2	Address/Data 2
38	CAD4	Address/Data 4
39	CAD6	Address/Data 6
40	RSRVD	Reserved
41	CAD8	Address/Data 8
42	CAD10	Address/Data 10
43	CVS1
44	CAD13	Address/Data 13
45	CAD15	Address/Data 15
46	CAD16	Address/Data 16
47	RSRVD	Reserved
48	CBLOCK#	Block ???
49	CSTOP#	Stop transfer cycle
50	CDEVSEL#	Device Select
51	Vcc	Vcc
52	Vpp2	Vpp2
53	CTRDY#	Target Ready
54	CFRAME#	Address or Data phase
55	CAD17	Address/Data 17
56	CAD19	CAD19
57	CVS2
58	CRST#	Reset
59	CSERR#	System Error
60	CREQ#	Request ???
61	CCBE3#	Command/Byte Enable 3
62	CAUDIO	Audio ???
63	CSTSCHG
64	CAD28	Address/Data 28
65	CAD30	Address/Data 30
66	CAD31	Address/Data 31
67	CCD2#	Card Detect 2
68	GND	Ground

Another representation (looking into card)


`GND`		`1`	`35`		`GND`
`CAD0`	`<->`	`2`	`36`	`-->`	`!CCD1`
`CAD1`	`<->`	`3`	`37`	`<->`	`CAD2`
`CAD3`	`<->`	`4`	`38`	`<->`	`CAD4`
`CAD5`	`<->`	`5`	`39`	`<->`	`CAD6`
`CAD7`	`<->`	`6`	`40`	`-`	`RSRVD`
`!CCBE0`	`-->`	`7`	`41`	`<->`	`CAD8`
`CAD9`	`<->`	`8`	`42`	`<->`	`CAD10`
`CAD11`	`<->`	`9`	`43`	`-`	`CVS1`
`CAD12`	`<->`	`10`	`44`	`<->`	`CAD13`
`CAD14`	`<->`	`11`	`45`	`<->`	`CAD15`
`!CCBE1`	`-->`	`12`	`46`	`<->`	`CAD16`
`CPAR`	`-->`	`13`	`47`	`---`	`RSRVD`
`!CPERR`	`-->`	`14`	`48`	`-`	`!CBLOCK`
`!CGNT`	`-->`	`15`	`49`	`-`	`!CSTOP`
`!CINT`	`-->`	`16`	`50`	`-`	`!CDEVSEL`
`Vcc`	`-->`	`17`	`51`	`<--`	`Vcc`
`Vpp1`	`-->`	`18`	`52`	`<--`	`Vpp2`
`CCLK`	`-->`	`19`	`53`	`-`	`!CTRDY`
`!CIRDY`	`-`	`20`	`54`	`-`	`!CFRAME`
`!CCBE2`	`-->`	`21`	`55`	`<->`	`CAD17`
`CAD18`	`<->`	`22`	`56`	`<->`	`CAD19`
`CAD20`	`<->`	`23`	`57`	`-`	`CVS2`
`CAD21`	`<->`	`24`	`58`	`<--`	`!CRST`
`CAD22`	`<->`	`25`	`59`	`-`	`!CSERR`
`CAD23`	`<->`	`26`	`60`	`-`	`!CREQ`
`CAD24`	`<->`	`27`	`61`	`<--`	`!CCBE3`
`CAD25`	`<->`	`28`	`62`	`-->`	`CAUDIO`
`CAD26`	`<->`	`29`	`63`	`-`	`CSTSCHG`
`CAD27`	`<->`	`30`	`64`	`<->`	`CAD28`
`CAD29`	`<->`	`31`	`65`	`<->`	`CAD30`
`RSRVD`	`---`	`32`	`66`	`<->`	`CAD31`
`!CCLKRUN`	`<--`	`33`	`67`	`-->`	`!CCD2`
`GND`	`---`	`34`	`68`	`---`	`GND`

AGP

2009-03-13T06:55:00.000-07:00

132 pin EDGE (AGP bus) connector at the computer motherboard

The Accelerated Graphics Port (also called Advanced Graphics Port) is a high-speed point-to-point channel for attaching a single device (generally a graphics card) to a computer"s motherboard, primarily to assist in the acceleration of 3D computer graphics. Many classify AGP as a type of computer bus, but this is something of a misnomer since buses generally allow multiple devices to be connected, while AGP does not. Some motherboards have been built with multiple independent AGP slots.

AGP dynamically allocates the PC"s normal RAM to store the screen image and to support some features. RAM used in this manner is referred to as the AGP Aperture. AGP originated from Intel, and it was first built into a chipset for the Pentium II microprocessor in 1997. AGP cards generally slightly exceed PCI cards in length and can be recognized by a typical "hook" at the inner end of the connector, which does not exist on PCI cards.

AGP versions includes:

AGP 1x (AGP 1.0), uses a 32-bit channel operating at 66 MHz with 1.5 V or 3.3 V signaling. This results in a maximum data rate for an AGP 1x slot of 266 megabytes per second. In comparison, a standard 32-bit 33 MHz PCI bus (which can be composed of one or more slots) is limited to 133 MB/s.

AGP 2x, using a 32-bit channel operating at 66 MHz double pumped to an effective 133 MHz resulting in a maximum data rate of 533 megabytes per second; signaling voltages the same as AGP 1x;

AGP 4x, using a 32-bit channel operating at 133 MHz double pumped to an effective 266 MHz resulting in a maximum data rate of 1066 megabytes per second; 1.5 V signaling;

AGP 8x, double pumped at 266 MHz to give a maximum of 2133 megabytes per second; 0.8 V signaling.

In addition, AGP Pro cards of various types exist. They require more power and are often longer than standard AGP card (though they only connect to one AGP slot). These cards are usually used to accelerate the professional computer-aided design applications employed in the fields of architecture, machining, engineering, and similar fields.

Pin	Name
A1	+12 V dc
A2	spare
A3	Reserved* Ground
A4	USB-
A5	Ground
A6	INTA#
A7	RST#
A8	GNT#
A9	VCC 3.3
A10	ST1
A11	Reserved
A12	PIPE#
A13	Ground
A14	Spare
A15	SBA1
A16	VCC 3.3
A17	SBA3
A18	Reserved
A19	Ground
A20	SBA5
A21	SBA7
A22	Key
A23	Key
A24	Key
A25	Key
A26	AD30
A27	AD28
A28	VCC 3.3
A29	AD26
A30	AD24
A31	Ground
A32	Reserved
A33	C/BE3#
A34	Vddq 3.3
A35	AD22
A36	AD20
A37	Ground
A38	AD18
A39	AD16
A40	Vddq 3.3
A41	FRAME#
A42	Spare
A43	Ground
A44	Spare
A45	VCC 3.3
A46	TRDY#
A47	STOP#
A48	Spare
A49	Ground
A50	PAR
A51	AD15
A52	Vddq 3.3
A53	AD13
A54	AD11
A55	Ground
A56	AD9
A57	C/BE0#
A58	Vddq 3.3
A59	Reserved
A60	AD6
A61	Ground
A62	AD4
A63	AD2
A64	Vddq 3.3
A65	AD0
A66	SMB1
B1	spare
B2	+5 V dc
B3	+5 V dc
B4	USB+
B5	Ground
B6	INTB#
B7	CLK
B8	REQ#
B9	VCC 3.3
B10	ST0
B11	ST2
B12	RBF#
B13	Ground
B14	Spare
B15	SBA0
B16	VCC 3.3
B17	SBA2
B18	SB_STB
B19	Ground
B20	SBA4
B21	SBA6
B22	Key
B23	Key
B24	Key
B25	Key
B26	AD31
B27	AD29
B28	VCC 3.3
B29	AD27
B30	AD25
B31	Ground
B32	AD STB1
B33	AD23
B34	Vddq 3.3
B35	AD21
B36	AD19
B37	Ground
B38	AD17
B39	C/BE2#
B40	Vddq 3.3
B41	IRDY#
B42	Spare
B43	Ground
B44	Spare
B45	VCC 3.3
B46	DEVSEL#
B47	Vddq 3.3
B48	PERR#
B49	Ground
B50	SERR#
B51	C/BE1#
B52	Vddq 3.3
B53	AD14
B54	AD12
B55	Ground
B56	AD10
B57	AD8
B58	Vddq 3.3
B59	AD STB0
B60	AD7
B61	Ground
B62	AD5
B63	AD3
B64	Vddq 3.3
B65	AD1
B66	SMB0

The AGP bus is 32 bits wide, just the same as PCI is, but instead of running at half of the system (memory) bus speed the way PCI does, it runs at full bus speed. This means that on a standard Pentium II motherboard AGP runs at 66 MHz instead of the PCI bus"s 33 MHz. This of course immediately doubles the bandwidth of the port; instead of the limit of 127.2 MB/s as with PCI, AGP in its lowest speed mode has a bandwidth of 254.3 MB/s. The AGP specification is in fact based on the PCI 2.1 specification, which includes a high-bandwidth 66 MHz speed that was never implemented on the PC.

This reserved pin should be connected to Ground

Source:www.pinouts.ru

15W Fm-transmitter

2009-03-13T06:50:00.000-07:00

It was five years ago when I did an attempt to build my first fm-transmitter. It ended in a giant faillure. The only thing it did was interferring with our tv-set. Looking back it was due to the lack of information I had. A schematic was my only help. Now, five years later, I know a lot more about electro-technics. So I searched for a schematic of a stable, tested fm-transmitter with a far reach. I will put all information you'll have to know in my page. I made drawings to make things clearer. As said before: I'm still building it, so I will add information every time I made progress. It would be wise for you out there not to start building untill I'm ready and have tested it. It has been succesfully built before, but my succes will give you a double security. I remind you of the fact that I can also fail.

Intro

Building a good fm-transmitter(88-110Mhz) begins with getting a good schematic. You don't have to understand the precise working of the transmitter to build it. But some basic information won't harm. A transmitter alone is, as you probably know, is not enough to start your radio-station. In the simplest form you need 4 things. First an input device such as an amplifiler you also use with your home-stereo.
You can also use a walkman. Details about input-devices in the page: "Input". Second you need a regulated power-supply. In this case a 14-18 Volts/2,5-3,5 Ampere. One of the most influencial things you need is antenna and coax-cable. More about this later on. And finally the transmitter itself. You can devide the transmitter in two main parts: the oscilator and the amplifiler. The oscilator converts electric sound information into electromagnetic waves. The amplifiler gives these waves
a bigger amplitude.

Building

It's stable and has output of 15-18 watts. This enough to terrorize your wide surroundings at the fm-band.

The most often used technique to connect the components to each other is soldering them on a double sided copper-board. Another way is connecting the components floating. It is cheaper but very tricky. Below you see the copper-board layout(PCB). I designed it looking closely at the root scheme.

Full size PCB:
PCBGRID.GIF

To get this pattern in copper surface you use a acid bath. Use a water-resistant permanent marker to paint your own copper-board black in the pattern the shown above. Color the back side ompletely black. The grid-squares are 0,5*0,5 cm each.

When the acid has eaten the non-painted copper away you must remove the complet thin layer of black paint with sandpaper. Don't remove too much copper with it.

So, now you have the surface to solder the electric components on.

Now a few basic rules for good soldering:
1. Use a special electronics-solderingrod with a slim top.
2. Use soldering-metal with an anti-oxidant-fluid core.
3. Don't heat the components! Heat the connection-point on your PCB.
4. Make sure that the surface is not too smooth.
5. Don't use too much metal.
6. Don't let the soldering metal form a bridge beetween two copper-surfaces.
7. If you're smart you start from the middle of your prepaired board.
In this way you'll have enough space.

Below the schematic. The yellow lines are pieces of copperboard that devide the transmitter in 3 parts. This is essential. Without them, internal interferrence will ruin your signal.

This picture is the coldwater-version... For the detailled version:

PCBCOMPLETE.GIF

Components

For readable version:

COMPON.GIF

There are some components that need extra attention. Transistors usually have 3 or 4 different
wires comin' out. If you connect these wires in the wrong way the transmitter won't work. It may even explode. The picture below shows how to prevent from such an event.

You can find the numbers and letters back in the soldering schematic.

Coils also require extra attention. You can buy the coils trough ferrite in the shop, but the other ones have to be made yourself. Use 1mm AgCu wire. A coil like 7x/d=10mm/l=15mm, goes round 7 times, has an diameter of 10 millimeter and is long 15 millimeters. The best way to make a coil is to bend it around a pencil or other cilindrical shaped object tight. The diameter of the object is always d-coil minus 1 mm. In this case 9mm. As I said: bend the wire round (in this case 7times) with the revolves tight together. To get the desired length stretch the coil when still around the pencil

READ THIS E-MAIL I RECEIVED

erwin.huybreghts@verhaert.com

Hello,

just to give some input: I have built the 15W FM transmitter you describe about 4.5 years ago.
The PCB lay out and component selection is still the same as it was then and after some modifications, I had an average output power of 16.8W @ 98.6 MHz (measured with Rhode and Schwarz equipement). You will need additional filtering on the power lines otherwise a stable power supply for the modulating circuit cannot be guaranteed. The legs of the modulating diode are, at best, kept long for extra capacitance. This to make sure you fall within the FM band because before I did that, I had
problems falling withing the 88-108 MHz. I was actually interfering with the police and fire brigade radio bands (Belgium). Of course, this is not the intention. I also advice you and readers to carefully check the orientation of the BLY88 because my professor blew one up due to lack of specification and inclarities in the datasheets (the actual pin out of the component changed a few years ago, resulting in a swapped emitter and collector - no good if you position it wrong!!! (the white cap flies of)). You will also need to play with the spacing between the windings of the different coils in order to get a good coupling between the different stages. I short circuited parts of the coils and made them smaller than specified to have near-optimal coupling. I also added extra ferrite bead coils for extra decoupling of the power lines, and used a very good shielding. Above 16.8W there is coupling (primarily through the air) between the output and the modulating/input stage and oscillation occurs. So for I have not found any other solution than lower the output power. Both extra decoupling
and extra shielding had no effect (my transmitter is built into a fully closed aluminium box with seperating plates that are fully connected to the case or ground plane on the PCB, except from where tracks run (0.5mm spacing provided)). Also, use a good heat sink for the last power stage!!!
I hope this information will be usefull. If you have any questions, please ask.
Kind regards,

Erwin

Erwin Huybreghts

Electronic Engineer
Space applications and space instruments division
Verhaert D&D
Hogenakkerhoekstraat 9
9150 Kruibeke
Belgium

Tel.: +32 (0) 3/250.14.50
Fax.: +32 (0) 3/253.14.64

4 Transistor Tracking Transmitter

2009-03-13T06:49:00.000-07:00

4W FM Transmitter-2

2009-03-13T06:48:00.000-07:00

TECHNICAL CHARACTERISTICS:

Stabilised tendency of catering: Vcc=12~16V

Frequency of emission: 88~108MHz

Consumption: 100~400mA

Materially:

The resistors are 1/4W.

R1, R2

10KOhm

R3

47Ohm

C1, C2

1nF

C3

4,7uF/16V

C4, C7, C8

0~45pF trimmer

C5, C6

10pF

C9

100nF

L1

4 turns, 7mm diameter *

L3

3 turns, 7mm diameter *

L4

5 turns, 7mm diameter *

L2

RFC (resistance 1MOhm with wrapped around her inductor of enough coils from fine isolated wire. Scratch of utmost inductor and you stick in utmost the resistance making thus a parallel L-r circuit.)

T1, T2

2N2219

ANT

Simple dipole l/2.

MIC IN

Microphone dynamic or other type. (It can also connected to a cassette player unit)

* The inductors is air from wire of coaxial 75W or other 1mm roughly.

Regulations:

With the C4 we regulate the frequency.

With their C7, C8 we adapt the resistance of aerial (practically to them we regulate so that it is heard our voice in the radio as long as you become cleaner).

Notes:

The T2 wants refrigerator.

Pulse-width modulation : PWM

2009-03-06T08:21:00.001-08:00

	Circuit Description :
The Pulse-width modulation (PWM) circuit in figure1 it works by making a square wave with a variable on-to-off ratio, the average on time may be varied from 0 to 100 percent. The IC 555 are main of this circuit which making a square wave with a variable on-to-off ratio, In put Frequency of cuitcuit we fix at 1 KHz

Figure1 Schematic of Pulse-width modulation : PWM

Telephonelamp 1700W

2009-03-06T08:19:00.000-08:00

Circuit Description :

The telephone or phone is a telecommunications device which is used to transmit and receive sound (most commonly voice and speech) across distance.
The circuit below show simple circuit of the Telephonelamp 1700 W.

Figure1 Schematic of Telephonelamp 1700W

Figure 2 Completed Circuit of Telephonelamp 1700W

Figure 2 Show Completed circuit The Telephonelamp 1700W and Applied

Bounceless switch

2009-03-06T08:14:00.000-08:00

This is a simple bounceless switch which use NOR gate CMOS CD4001

Phase shift oscillator with NOT gate

2009-03-06T08:13:00.001-08:00

Phase shift oscillator can build from CMOS NOT gate.This is an example which use CD4049 CMOS .The output frequency is about 1/3.3RC ___Hz

Voltage Doubler

2009-03-06T08:11:00.000-08:00

This is a simple voltage doubler circuit which has the output voltage is 2xVin

Short Circuits : CD4011

2009-03-06T08:10:00.000-08:00

The CD4011 has four separate 2-input NAND gates which you can use independently and can use widely than 7400/74LS00.

Short Circuits : CD4001

2009-03-06T08:09:00.000-08:00

The CD4001 has four separate 2-input NOR gates which you can use independently.It also has hi-impledance input and can use widely than 74LS02.

simple circuit to control DC motor on/off

2009-03-06T08:07:00.000-08:00

This a simple circuit that use to turn on/off 12V DC motor with TTL control signal input. The BD139 should instal with heat sink.

Light flasher circuit

Interfacing CMOS with TTL

2009-03-06T08:06:00.000-08:00

Interfacing when it has the same power supplies.

Interfacing when power supplies is not the same level.

CMOS logic clock generator

2009-03-06T08:05:00.000-08:00

If you want to generate clock with CMOS you can do as the follow picture.The typical resister values is 100K and Capacitor is 0.01-0.1uF.The output frequency is about RC/2.2 ___Hz

Clock pulse Generator with CD4049

2009-03-06T08:03:00.000-08:00

If you want to generate clock with CD4049 CMOS you can do as the follow picture.The typical resister values is 100K and Capacitor is 0.01-0.1uF.The output frequency is about 1/1.1RC ___Hz

Electro meter circuit

2009-03-06T08:00:00.000-08:00

This is a simple electro meter circuit.This circuit will detect electrostatic charge from the any material such plastic,comb etc.
It can measure up to 30 cm from the target material.
To use this circuit first adjust R2 when the antenna near the material until Amp meter read 1 mA.

Motorcycle Low Voltage Warning

2009-03-06T07:57:00.000-08:00

Parts List:
   U1 = LM339, Op-Amp
   Q1 = 2N3906, PNP transistor.
D1,D2 = 1N4148, signal diode
  ZD1 = 1N5235, 6.8V zener diode
   R1 = 1K
   R2 = 10K, trim pot
R3,R5 = 10K
   R4 = 1M
   C1 = 4.7uF, 25V, electrolytic capacitor
Buzzer = 12V, 4mA

This circuit is connected to your motorcycle. It's tapped into a circuit thats only powered with the key "ON". If you turn the bike off with the kill-switch and leave the key on, as you know, the headlight will stay on and quickly drain the battery.

With this circuit, once system voltage is down a volt and a half or so, the first comparator turns on Q1. Q1 begins charging capacitor C1. After about 6-8 seconds, the voltage on C1 equals the reference zener voltage and the second comparator turns on the beeper. This way the low voltage condition must be sustained, i.e. won't start chirping while cranking the starter, but still goes off soon enough to keep you from getting too far from your bike. Thanks R.P!

Waterpump Safety Guard for Fish-pond

2009-03-06T07:56:00.000-08:00

The circuit below was developed to guard the fish pond. In this case to prevent that the pump sucks just air when the waterlevel get below the pump. When the waterfilters get saturated and dirty, the water level behind the filter gets to an unacceptable level. You can see this when the pump also produces airbubbles in the water.

Because you are not all day peeking if this is the case, I connected the pump via a Solid State Relais, which acts as a power switch mounted in one of the AC wires and is controlled by the circuitry below.

The sensor is fabricated using two sturdy solid *copperwires which are mounted approximately 1cm () apart in the water after the waterfilter. The conductivity of the water is sufficient to pull the input of the first IC (IC1c) high. The output of IC1d will then also be high. (* see note)

This output signals the R-S Flip-Flop formed by IC1a and IC1b.
Often the condition is correct when you power up, which is indicated by the green led. However, if the red led is lit, just press the Reset switch to put the circuit in the proper operational condition. The current flowing through the green led is also fed through the diode in the Solid State Relay, activating the relays and the starting the pump.

If for some reason the water level is getting low and the copper wires no longer touch the water, the input of the first IC is pulled low and consequently also the ouput of the IC behind that. The R-S Flip-Flop flips to the other condition and the green led goes out and also the pump and the red led will be lit to indicate 'something' is wrong. In this case the waterlevel.

When you're ready after the filters have been cleaned, the only you have to do is press the Reset button to activate the pump again. This way unnecessary damage to the pump is prevented.

The copper wires will need regular cleaning to make sure they conduct.

If you have questions about this circuit, please direct them to Jan Hamer or visit his website in the Netherlands (if you can read Dutch).

Published & Translated from Dutch into English with permission of Jan Hamer, The Netherlands.

Wailing Alarm Siren

2009-03-06T07:54:00.000-08:00

Parts List:
R1,R5 = 4.7K            C1,C4 = 100uF/25V, electrolytic
  R2 = 47K             C2,C3 = 0.01uF (10nF), ceramic
  R3 = 10K                Q1 = 2N3702 (NTE159, TUP, etc.)
  R4 = 100K          IC1,IC2 = LM555, NE555, uA555
 *Rx = See text           LS = Loudspeaker (see text)
 
A complete KIT plus Printed Circuit Board will be available soon.

Notes:
This circuit provides a warbling sound to any alarm circuit. IC2 is wired as a low frequency astable with a cycle period of about 6 seconds. The slowly varying ramp waveform at C1 is fed to PNP emitter follower Q1, and is then used to frequency modulate alarm generator IC1 via R6. IC1 has a natural center frequency of about 800Hz.
Circuit action is such that the alarm output signal starts at a low frequency, rises for 3 seconds to a high frequency, then falls over 3 seconds to a low frequency again, and so on.

* The Loudspeaker LS and the resistor marked "Rx" should be together 75 ohms. If you have a standard 8-ohm speaker then Rx is 67 ohms. The nearest value is 68 ohms. So for a 8 ohm loudspeaker Rx is 68 ohms. For a 4 ohm loudspeaker Rx is 71 ohms, for a 25 ohm loudspeaker Rx is 50 ohms, etc. The Rx value is not very critical. It is just there as some sort of volume control, experiment with it.

C2 and C3 are 0.01uF (10nF) and a simple ceramic type will do the job. I tested the circuit at 9, 12, and 15 volt. My personal choice is the 9 volt alkaline type for battery operation, or 12 volt for use with a small powersupply. The so-called 9V NiCad will not work properly. The actual voltage for this NiCad type is actually only 7.5V (6 cells x 1.2V = 7.5V)

Just in case you're wondering, output pin 3 of IC2 is NOT connected! In the prototype, I used LM555 timers.

Theremin

2009-03-06T07:53:00.000-08:00

Parts List:
Resistors are 1/4W, carbon, 5% tolerance (or better).

R1 = 100K                             IC1 = 4069
C1 = 0.02 (22nF)                LDR1,LDR2 = Light Dependent Resistor
C2 = 0.1uF (100nF)                     T1 = Audio Transformer, 1000:8
C3 = 100uF/16V electrolytic            S1 = On/Off switch
C4 = 100uF/16V electrolytic

Note:

This circuit uses a common CMOS 4069 IC. The MC14069 is pin for pin compatible.

The 4069 has six inverters, but only three are used.

The first two inverters operate as an digital audio oscillator, and the third as an audio transformer low-gain linear audio amplifier.

Modifying a Servo

2009-03-06T07:51:00.000-08:00

Project Background Info:
I was in need to modify four expensive JR-DS8231 Ultra Digital servos to rotate 360° instead of the standard 130° or something. The mods were required so they could be used with a tethered blimp. The infra-red and night vision camera equipment is mounted underneath the blimp on a special fabricated aluminum cage and is radio controlled (R/C). I choose a digital 10-channel radio transmitter merely for the needed channels and reliability of JR products.
The project was handed to me by our local "Land Resources" department, for my extensive experience with all sorts of radio control systems and products.

Since modifying the digital servos was not gone work, I opted for four cheapie analog servos, Hobbyco C60 (made by HiTec). The little pot inside the servo is 5K and so has to be replaced with 2.5K resistors each. Since 2.5K is not standard stock, I opted for 2.4K resistors. Worked out fine. (I thought maybe publishing my findings could possibly assist in helping someone else obtain the same goals). Check the pictures at the bottom of the page for the modification sequence. I soldered a couple days later two small ceramic capacitors (0.01uF) over the servo motor power connections to eliminate 'servo-creep' on a Futaba servo. Worked fine. See picture 16-a down below.
Also, remove the notch (or stopper) from the gear with the bearing. Snip it off with a cutting plier and then use an exacto knife to clean up the rest.

Underneath this blimp is a system with 2 infra-red cameras which takes a variety of pictures from the soil at different locations. The different colors of the soil in the pictures are then analyzed in regards to soil looseness, clay, (hot)rock, type, etc. The system which houses these cameras had to extremely safe. The 2 cameras alone are expensive at a cost of $35,000 each and weighing almost 4 pounds each plus the battery packs and R/C equipment and weight of the aluminum frame (cage) itself. Total weight to be carried by the blimp, at one time, was about 15 pounds (Can). Cameras can be switched with Infra-red cameras or night vision, etc.

ScanMate

2009-03-06T07:41:00.000-08:00

Introduction:
What exactly is 'ScanMate'? Read on. It never seems to fail. You wake up in the morning, turn on the radio news, and there it is: A major fire across town, a drug bust in the local park, police chases, or an airliner forced to make an emergency landing along the highway. Such events always seem to happen just after you have turned off your scanner and gone to bed, or left the house.

Some of the hottest action to come over the air waves for months, and you missed it....that is, until ScanMate! With ScanMate connected between your scanner and a tape recorder (via the recorder's microphone or auxiliary input and its remote start jack), you will never have to worry about missing any of the action again.

ScanMate is similar to several of the available commercial units, but offers greater flexibility. The ScanMate unit has a 'level' control that allows it to be used successfully with any type of scanner--portable or base unit--regardless of its output-amplifier configuration. It also provides control over the length of time the recorder continues to run after the transmission ceases. Also included in the circuit is a switch that allows you to select either automatic or manual operation.

When ScanMate is set to the auto-mode, the recorder's motor operates only during transmissions. In the manual-mode, the motor is activated whenever any of the recorder's functions (play, rewind, etc.) is selected. That allows all the interconnection cables to remain in place when you decide to rewind and listed to the tape. A speaker in/out switch is provided to allow monitoring (via the circuit's build-in speaker) while recording. In addition, ScanMate provides both microphone and line-level outputs, so that even the least-sophisticated recorders can be used.

How It Works:
Figure 1 is the schematic diagram of the ScanMate circuit. Audio coming from the scanner's earphone or speaker jack is fed to the circuit via J1. Jack J2, which is wired parallel with jack J1, provides a line-level output for input to the recorder via its auxiliary input jack. The signal is also fed through a voltage divider, consisting of resistors R1 and R2, which attenuate the signal for the mic-out jack J3.

Switch S1 is used to switch speaker LS1 in and out of the circuit. In the 'out' position, a 10-ohm resistor, R3, is switched into the circuit in place of the speaker's 8-ohm impedance, providing a fairly constant lead for the scanner's output. Capacitor C1 blocks any DC voltage that might be present. The signal is then fed to the inverting input of U1a (1/2 of a LM1458 dual op-amp), the gain of which is set to about 150 by the R4/R5 combination. The output of U1a at pin 1 is rectified by diode D1. The peak voltage is fed across C2 to the non-inverting input of U1b, which is configured as a voltage comparator. When the voltage at pin 5 is higher than that set by P1 (the level/sensitivity control) at pin 6, the output of U1b swings to near the positive supply rail, lighting the green half of LED1, a bi-color Light Emitting Diode.

Resistor R7 limits the current to LED1. The high at U1b's output (pin 7) also turns on T1 which, in turn, activates a reed relay, Ry1, causing its contacts to close. The contacts of the relay act as the tape-recorder's motor on/off switch. When the voltage at pin 5 of U1b is lower than that at pin 6, its output swings close to the negative supply rail, illuminating the red half of LED1, and at the same time turning off T1 and Ry1, as well as the tape recorder's motor.
The discharge rate of C2, combined with the setting of P1, determines the time the recorder runs after the last transmission. With an LM1458 Op-Amp, and its relatively low input impedance a C2 value of 0.1uF provides an ideal discharge rate. However, if a high input impedance op-amp is used, such as one with JFET inputs, C2's value should be increased to around 5uF (4.7uF is ok) and the value of P2 should be adjusted to near 10-megohms. Some experimentation with the setting of P2 -- which value should be between 5 and 30 megohms -- may be necessary to achieve optimum performance. I only used the adjustable potmeter (P2) to find the optimum setting and then measured that resistance and replaced the pot with an appropriate value of a resistor (Rx). Works.

Diode D3 and capacitor C3 are used to shunt any harmful spikes produced by the relay's coil away from T1. Switch S2 is the 'Manual/Auto' select switch. When S2 is closed, it acts like the closed contacts of the relay, turning on the tape-recorder motor.
The circuit is powered from a dual 8-volt power supply, (see Fig. 2) consisting of a handful inexpensive components. The AC line voltage is fed through S3 (the on/off switch) and a Fuse of 0.25 Amp (250mA) to power transformer TR1, which reduces the 117V line to 6.3 volts. That voltage is then full-wave rectified by D4 and D5, and filtered by electrolytic capacitors C4 and C5, to provide a suitable power source for the circuit.

Parts List:
R1 = 47K                   C1 = 1uF/16V            S1 = on-on, SPDT Switch
R2 = 470 ohm         C2,C3,C4 = 0.1uF (ceramic)    S2 = on-off, SPST Switch
R3 = 10 ohm             C5,C6 = 1000uF/25V         S3 = on-off, SPST Switch (115VAC)
R4 = 22K          D1,D2,D3,D4 = 1N4001            Ry1 = Reed Relay, 5V-1A
R5 = 3M3                   T1 = 2N2222            TR1 = Transformer, 12.6V CT, PC-Mount
R6 = 100 ohm               U1 = LM1458                  Socket for U1 (8-pin)
R7 = 330 ohm              LS1 = Speaker, 8-ohm    >>Radio Shack<< or Tandy part #'s
R8 = 100 ohm         J1,J2,J3 = Jacks, 3mm*
P1 = 100K, Lin             J4 = Jack, 2mm*        Notes: 3M3 (R5) same as 3.3M
P2 = 20M 10-turn         LED1 = Bicolor LED*             µ = micro or u
(Rx) optional, see text

A KIT for this powersupply is available here: [ScanMate KIT]

Construction:
There is nothing critical about the circuit's layout, and its okay to use perfboard, but using the printed circuit board pattern shown in Fig. 3 helps to simplify matters. Jacks J1 to J4 should be of whatever type matches the inputs to your scanner and tape recorder. In my case, the mic/aux/audio jacks are the standard 3mm and the remote jack 2mm in the ScanMate prototype.

Fig. 4 is the parts-placement diagram for ScanMate's printed circuit board. Note that several components for the circuit are mounted off-board on the front and rear panel of the project enclosure. After positioning the off-board components, run short lengths of hookup wire from the appropriate points on the board to those components.

Turning to the bi-colored LED used in the circuit; if a similar unit cannot be found, the two-color unit can be replace by two discrete LED's. Of course, it will be necessary to supply an appropriate dropping resistor for each unit; or if you decide to hook them up back-to-back (duplicating the unit's schematic symbol), you may have to play with the value of the dropping resistor.

I used a Radio Shack 12.6 volt, center-tapped (ct) transformer in the power-supply of his prototype. I was unable to obtain the 300mA version so saddled for the 500mA type which meant modifying the PCB a bit since the transformer is larger in size. The output of the transformer is taken from its center tap, thereby providing 6.3 volts AC for the rectifier circuit. If you have difficulty in locating a similar unit, you might consider using a 12-volt transformer (with sufficient current rating), along with a 7808 and a 7908 (positive and negative, respectively), 8-volt, three terminal regulators. If you choose to go that route, be sure not to overlook the filter capacitors.

I have not experimented with an DC-type adapter but don't see why that should not work. If you have a 8 or 9 volt DC adapter of at least 300mA or better, try it. Saves the cost of the power supply parts + powercord in Fig. 2.

As for the enclosure itself, there are a couple of things to watch for should you decide to use a metal cabinet to house the project (as in my case). A lot of tape recorders with positive grounds or other unusual circuitry react violently to having either side of their remote start switches grounded. To prevent that problem, the remote start jack (J4) should be covered with heat shrink, or whatever, to keep the contacts completely isolated from ScanMate's other circuitry. You will most likely hear tremendous 'hum' if the remote jack is improperly isolated from the metal panel. (if, of course, you use a case with metal front and rear panels). You may have noticed that, unlike the other jacks, the remote jack is not connected directly to ground.

TR1 is a pc-mountable 12.6volt/300mA Center Tapped transformer. I purchased mine at Radio Shack: #276-1385. Some modifications were required to the PCB-layout to make the transformer fit nicely. Just in case you don't have a lot of experience with electronics and you're wondering why the schematic shows 6.3V and the parts list 12.6V. The transformer is a so-called 'center-tapped' model which means 6.3V - 0 - 6.3V. Either side of the '0' provides 6.3V. The '0' is the center-tap (Gnd.), or CT for short. We only use one side of the transformer with the center tap. CAUTION: Because of the +8 and -8 volts, the above circuit ONLY uses the ground coming from the center-tap of TR1!
In addition, because the circuit derives power from a 117-volt AC outlet, make certain that the board is mounted in its enclosure on standoffs to prevent the board from coming in contact with the cabinet.

Making a neat cutout for speakers is always a problem, if you're not handy with mechanical equipment, but can be easily solved by putting the opening at the bottom of the cabinet, where imperfections won't be noticed. I solved the problem by drilling 3 millimeter holes in a half star pattern. Looks really good. Anyone can drill a couple of holes right?
Check my Radio Shack data sheet for partnumbers; makes things easier when you visit the Radio Shack/Tandy store.

Just in case you have any problems finding some of the parts: You can replace the 2N2222 for a NTE123A (not AP), a 2N2219, BC107, or a TUN type as specified in Elektuur (Elektor), or try something else (if it works it works right?). By the way, a 2N2222 is the same as the MPS2222A type from Radio Shack. If you can't find the LM or MC1458, use the NTE778A, or the 276-038 model from Tandy/Radio Shack; they are all pin-for-pin compatible as far as I know. The 1N4001 diodes can be substituted with a NTE116 or the #276-1101 model from Radio Shack. An 1N4002 or 1N4003 model will work just fine also, they just have a higher PIV. Transformer TR1 is available from Radio Shack as the #273-1384 6.3v/300mA. The general term for this type transformer is "filement" transformer because of the 6.3V. But use what's available in your area.

Using The ScanMate:
After connecting ScanMate, a scanner, and a tape recorder together, flip the speaker switch (S1) to the 'on' position and turn the 'level/sensitivity' potentiometer (P1) fully counter-clock-wise. Next, find a busy channel on the scanner and put the tape unit into the record mode. LED1 should be red, meaning the tape is stopped. Slowly turn the P1 potentiometer clockwise until the bi-colored led turns green. At that point, your tape recorder should be running, recording everything coming over the scanner. Turn back a little back until the red led comes on again and the tape recorder stops. Monitor the whole thing for a bit and re-adjust if necessary.

Now switch to a silent channel and check how long it takes for ScanMate to shut off the recorder. If the delay isn't right, turning the 'Level' potentiometer clockwise (up to a certain extend), will increase the time before shut-off, turning it counterclockwise shortens the delay. Again, keep in mind that the level of delay is limited by the values of P1 and C2.

Fun and Games with Transistor Astables

2009-03-06T07:40:00.001-08:00

This project is all about fiddling with devices. Often people jump into electronics at the integrated circuit (IC) level, wiring IC's up without much knowledge of what's going on underneath. This project doesn't involve any IC's, just a few discrete components. That doesn't mean it's boring as there's plenty to be gained by building this circuit and having a look at how it works.

Figure 1 â€“ Astable Circuit

Figure 1 shows the Astable circuit. It constantly switches its output high then low at a frequency dependent on R3, R4, C1 and C2. Given that there are only two states (high and low), transistor Q1 and Q2 are turned on independently, such that the LED(D1) and LED(D2) light up at alternate times.

The best way off trying to understand this circuit is to assume one of the transistors (lets say Q1) has just turned off. Before the switch occurred, the voltage across C1 was 5.4V (6V at +ve end and 0.6V at â€“ve end). When Q1 suddenly turns on C1 is still charged but the +ve end has been dragged down to 0V. This means the â€“ve end must also fall by the same voltage i.e. it falls to -5.4V. This negative voltage is applied to the base of Q2 turning it off. However the â€“ve voltage is reduced at Q2â€™s base via a current charging up C1 through R3. When the voltage reaches 0.6V at the base of Q2, Q2 will turn on, causing the voltage at Q1â€™s base to drop to -5.4V turning Q1 off. The cycle repeats continuously and the result is an oscillating Astable circuit.

Figure 2 shows an oscilloscope trace of the two outputs (Q1 and Q2 collector voltage).

Figure 2 â€“ Oscilloscope Trace (2V/division)

You can fiddle around and experiment with different component values to change the circuit frequency. Also, changing the values so they are no longer symmetrical (e.g make C1 and C2 different) will change the duty cycle such that one LED is on longer that the other.

Have a go at building this circuit and ask any questions in the electronicprojects.org forums.

Note that the transistors can be any general purpose small signal NPNâ€™s. I used BC108â€™s.

Phase Controlled Lighting System

2009-03-06T07:25:00.000-08:00

This project was developed to provide some pleasant room lighting as the author was fed up with inflexible standard incandescent light bulbs used in most rooms. Specifically it details the use of five Low Voltage Lamp units as up-lighters placed around a room. Each lamp can be turned on/off individually and all lamps can be dimmed from full brightness down to zero brightness. Figure 1 shows one of the lamps mounted to a wall.

Figure 1 â€“ Halogen Lamp Mounted as Up-Lighter

Brightness Control Basics

The lamps used, in this project, are five 20W, 12V Sealed lamp units that have become popular recently. There are two common ways of controlling lamp brightness. The first is to power the lamps from 12V DC (Direct Current) and the use PWM (Pulse Width Modulation) to vary the average voltage across each lamp. The second way is to power the lamps from AC (Alternating Current) and then control the proportion of the AC cycle for which current is allowed to flow though each lamp.

It was decided that obtaining a DC supply capable of powering five 20W lamps would be too expensive (in terms of high current rectifier and smoothing capacitors). Therefore the Phase Controlled AC operation was selected.

Figure 2 â€“ Triac Connections

Click to enlarge.

Figure 3 â€“ Illustration of Phase Control

Figure 2 shows a simple circuit used for phase control and figure 3 shows some of the expected waveforms from this circuit.

Looking firstly at figure two, a triac is used as a switch which is in series with the halogen lamp also in series with the 12V supply. When the triac is conducting, current flows through the lamp and when it is not, no current flows. This is the basic mechanism for brightness control in the lamp.

Figure 3 shows the relationship between the sinusoidal supply voltage, the gate signal of the triac and the resultant lamp current. It can be seen that when the triacâ€™s gate pulse arrives the triac conducts and will carry on conducting until the sinusoidal supply has dropped to zero volts. Figure 3 shows the condition of half brightness, where the lamp is on for half of the AC cycle.

The job of the rest of the circuit is then to detect a zero crossing of the 12V supply, provide a variable timer, and at the end of this time provide the triac gate pulse. This has the effect of â€˜firingâ€™ the triac at a variable time after the zero crossing event and hence allowing variable brightness.

Circuit Description

Click to enlarge.

Electrometer

2009-03-06T07:23:00.002-08:00

The following circuit is an electronic approximation of the ‘gold leaf electroscope’, except that this electrometer indicates polarity as well as electric field magnitude. It is incredibly sensitive! It will detect a television or an electrostatically charged comb from the other side of a room. It can even ‘see’ people moving about!

The neon bulb serves two purposes. It provides leakage at the FET gate and also helps to defend the FET against an electrostatic discharge. Do not omit the neon bulb – the FET won’t get the proper biasing without it. Ideally, the neon bulb should be in darkness, though the circuit seems to work okay with the neon bulb illuminated. The only effect is that the meter ‘autozero’ has a much shorter time constant when the neon bulb is illuminated.

The meter can be of the ‘VU’ variety though meters in the range 100 μA to 1 mA can be made to work. You may need to change the value of the adjustable resistor if a meter of widely different FSD to that specified is employed. A source of small, cheap meter movements is those cheap battery testers – their meters tend to be in the range 0.5 mA to 1 mA.

You won’t be able to walk around with this electrometer – the needle will just kick between its end stops if you try. Instead, it should be operated on a firm surface and left to settle for a minute or two. Adjustment of the ‘METER CENTRE’ adjustment is inevitably a trial and error affair, as bringing your hand near the electrometer will probably alter its reading.

The probe can be just a few inches of wire. The impressive looking probe on my meter is nothing more than a redundant adapter from an emergency mobile phone battery! I provided an earth connection through the body of the switch in anticipation that I might need to use my hand to remove excessive charge from the probe, but I haven’t actually needed to do that yet.

MOSFET Prevents Battery Damage

2009-03-06T07:23:00.001-08:00

Sealed-lead-acid batteries, which find wide use in power-electronics products, such as UPS (uninterruptible-power supplies), inverters, and emergency lamps, supply power to the load whenever utility power is unavailable. When you restore utility power, a charger supplies the power to the load and charges the batteries (Figure 1).

You can add a diode to protect a load from current resulting from a reverse-connected battery. The diode, however, won’t protect a reverse-connected battery from the charger circuit. If the charger is on, a potentially dangerous current can flow into a reverse-connected battery. The battery voltage, which normally opposes the charging voltage, now aids it, which lets a higher current flow into the battery.

If you add an N-channel MOSFET to the circuit, you can protect the battery from this damaging condition (Figure 2). The MOSFET conducts only when the battery is correctly connected, which lets the battery charge or discharge. In this condition, the transistor gets forward-biased, which switches on the MOSFET. If the battery is reverse-connected, the transistor and MOSFET turn off, thus preventing current flow. This simple circuit provides reverse-battery protection in both charger and battery paths, thereby protecting the battery, the charger, and the load. You can use a microcontroller to measure battery current and make a decision on appropriate action, as well.

How To Save Your Wet Cell Phone!

2009-03-06T07:10:00.000-08:00

Most of us have experienced dropping or spilling liquid over our over priced sensitive cell phones or gadgets and lost them forever.

Most people try to save their gadgets the wrong way . ex using a hair dryer witch may force moisture further into the small components and giving your phone a complete knockout .

In this instructable i will show you how to increase the chances of saving your phone/gadgets from drowning.

Also If you wish to view the video of this instructable for a better understanding or a quick review of the hole project click below. http://www.videojug.com/film/how-to-save-a-wet-cell-phone-2'

Note for this instructable you will need :

1. One or more wet hand held gadgets.
2. One dry airtight container.
3. One pack of household cocking rice.
4. One or more small screwdriver.

Enjoy !

The most important thing you have to do is to get that phone out of the water as soon as possible don't just look dumb at it while it's drowning, act fast !

Remove it from the water [pic.1].[pic.2]

Even doe the phone was under water for only a few seconds the vibration function short circuited, resulting in the phone vibrating out of control to view this watch the video http://www.videojug.com/film/how-to-save-a-wet-cell-phone-2 or in [pic.3] .

So remember, removing it from the water as soon as possible makes the life/death difference !

As fast as you can remove the battery from the phone, don't waste time switching it off first, just remove the battery as soon as possible.[pic.1]

Using a small screwdriver take the phone apart as well as you can the more parts you remove the better but make sure you will manage to put everything back together once it's all dried out. [pic.2]. [pic.3]

Do not use a hair dryer (even on a "cold" mode) to dry out the phone, as this may force moisture further into the small components, deep inside the phone. If moisture is driven deeper inside, corrosion and oxidation may result when minerals from liquids are deposited on the circuitry. Using a hairdryer might be a temporary fix, but this will eventually cause component failure inside the phone.

Now, you will need to take your disasembled phone, a bag of regular dry household rice, and an airtight container.

Take the rice [pic.1] , and pour it in the container half way full [pic.2] , take all the phone components and put them in with the rice [pic 3] , place the cap on the container and give it a good shake [pic.4]

Now let them dry for around 2 days, The rice will absorb any remaining moisture from within small components and prevent corrosion and oxidation.

Open up the container...

And remove all the parts inside, inspect each and every one of them carefully , you may use a magnifying glass to make sure no moisture is kept within small parts.

Then carefully put everything back together, part by part ... add the battery and try to start your phone.

Congrats you probably save your phone...

Even doe my phone short circuited it's vibration function during this experiment after it was subjected to the rice treatment it fully recovered and now it's working perfectly . [pic 1. & 2.]

Also if you would like to see the hole thing in a video for better understanding and fast bookmarking view the video of the project here : http://www.videojug.com/film/how-to-save-a-wet-cell-phone-2

Here are some answers to a few questions you may ask :
1. If i had an iphone i would have used an iphone on this project. (and moisture & electricity work the same regardless of brand or features) so yes, you can save your iphone with this technique.
2. YES it really works !

NOTE : If your phone does not work, try plugging it into its charger without the battery, if this works, you need a new battery. If not, try taking your cell phone to an authorized dealer. Sometimes they can fix it. Don't try to hide the fact that it has been wet. There are internal indicators that prove moisture

Thank you !

LOW POWER 12,000 VOLT POWER SUPPLY

2009-03-06T07:09:00.000-08:00

If you need about 12,000 volts DC for an ion generator this circuit might be the ticket. It draws power from the 120vac power line but it uses a small 6KV camera flash trigger coil. The output signal is isolated from the power line. Although the circuit can only deliver about 5uA of current it can produce dangerous shocks, so be careful.

CAPS PROVIDE VOLTAGE BOOST TO SERIES REGULATOR

2009-03-06T07:07:00.000-08:00

This circuit adds some capacitors and diodes to a traditional transformer type series regulator circuit to extend the normal operating range. It can insure regulation during low line voltage conditions or it can squeeze a few more watts out of a plug-in-the-wall power adapter power supply.

ISOLATED AC CURRENT MONITOR

2009-03-06T07:00:00.000-08:00

This circuit uses a small AC current transformer from Magnetek to produce an isolated voltage proportional to the AC current in the primary winding. The transformer contains a single turn primary with a low 0.001-ohm resistance. It can easily handle 30 amps of AC current and provides at least 500vac of isolation. With the components shown, the output AC voltage is scaled so 1 amp of current produces 100mv of AC voltage.

Flashing-LED Battery-status Indicator

2009-03-04T06:40:00.000-08:00

Signals when an on-circuit battery is exhausted

5V to 12V operating voltage

Parts:

R1,R7__________220R  1/4W Resistors
R2_____________120K  1/4W Resistor
R3_______________5K6 1/4W Resistor
R4_______________5K  1/2W Trimmer Cermet or Carbon
R5______________33K  1/4W Resistor
R6_____________680K  1/4W Resistor
R8_____________100K  1/4W Resistor
R9_____________180R  1/4W Resistor

C1,C2____________4µ7  25V Electrolytic Capacitors

D1____________BAT46  100V 150mA Schottky-barrier Diode
D2______________LED  Red 5mm.

Q1____________BC547   45V 100mA NPN Transistor
Q2____________BC557   45V 100mA PNP Transistor

B1_______________5V to 12V Battery supply

Comments:

A Battery-status Indicator circuit can be useful, mainly to monitor portable Test-gear instruments and similar devices.
LED D1 flashes to attire the user's attention, signaling that the circuit is running, so it will not be left on by mistake. The circuit generates about two LED flashes per second, but the mean current drawing will be about 200µA.
Transistors Q1 and Q2 are wired as an uncommon complementary astable multivibrator: both are off 99% of the time, saturating only when the LED illuminates, thus contributing to keep very low current consumption.

The circuit will work with battery supply voltages in the 5 - 12V range and the LED flashing can be stopped at the desired battery voltage (comprised in the 4.8 - 9V value) by adjusting Trimmer R4. This range can be modified by changing R3 and/or R4 value slightly.
When the battery voltage approaches the exhausting value, the LED flashing frequency will fall suddenly to alert the user. Obviously, when the battery voltage has fallen below this value, the LED will remain permanently off.
To keep stable the exhausting voltage value, diode D1 was added to compensate Q1 Base-Emitter junction changes in temperature. The use of a Schottky-barrier device (e.g. BAT46, 1N5819 and the like) for D1 is mandatory: the circuit will not work if a common silicon diode like the 1N4148 is used in its place.

Note:

Mean current drawing of the circuit can be reduced further on by raising R1, R7 and R9 values.

Quick on-board Junction Tester

2009-03-04T06:38:00.000-08:00

Acoustic check of transistor and diode junctions

Also suitable as continuity tester

Parts:

R1,R9,R11,R12__100K  1/4W Resistors
R2,R3,R6________10K  1/4W Resistors
R4,R5,R10_______47K  1/4W Resistors
R7_______________1M  1/4W Resistor
R8_______________1M5 1/4W Resistor

C1_____________100nF  63V Polyester Capacitor
C2_______________1µF  63V Polyester or Multilayer Ceramic Capacitor
C3,C4___________10µF  25V Electrolytic Capacitors

D1____________1N4148  75V 150mA Diode

Q1_____________BF245 or 2N3819 General-purpose N-Channel FET

IC1____________LM358  Low Power Dual Op-amp

BZ1____________Piezoelectric sounder (incorporating 3KHz oscillator)

SW1____________SPST  Toggle or Slide Switch

Red Probe______Insulated probe, Multimeter-like
Black Probe____The same as above

B1______9V PP3 Battery

Clip for PP3 Battery

Comments:

Short circuits or broken pcb tracks can be easily recognized by means of a Multimeter, but this tool can give wrong results when testing the efficiency of a transistor or diode, unless the device under test is unsoldered and removed from the pcb.
A further shortcoming affecting such way of testing is the necessity to keep firmly the probes on the pins of the device under test and at the same time to turn the head continually to read the Multimeter display.
This device allows the user to concentrate on the (often problematic) pcb probes placement, because a short, a broken track, a good or burnt transistor or diode, will be signaled by a beep, as follows:

A train of short beeps (one per second) indicates an efficient diode or transistor junction
A train of one-second lasting beeps spaced by a very short silence (in practice an almost continuous beep) indicates a shorted junction or, on the contrary, a good pcb track
A lack of beeps indicates a broken junction or a broken pcb track

Circuit operation:

Both inputs of IC1A are connected together by two equal value resistors (R4 and R5) and to half the voltage supply obtained by means of the voltage divider R2 and R3. So, the same voltage should be present at both input pins.
In practice, half the voltage supply (i.e. about 4.5V) will be present at the inverting input (pin #2) of IC1A, but the constant voltage generator formed by R6 and D1, feeding the non-inverting input (pin #3) of IC1A by means of the voltage divider R7 and R8, clamps this pin to about 4.1 - 4.3V: this will cause the output of the op-amp to stay low.
If the circuit input (R2 to R3 junction) is shorted to negative ground (a condition equivalent to a shorted transistor junction) pin #2 of the op-amp will go to 0V and the voltage at pin #3 will decrease to about 0.3 - 0.35V (caused by the constant voltage generator mentioned above): the op-amp output will go high, activating the piezoelectric sounder.
When a real transistor or diode junction is connected to the input of the circuit instead of shorting the input probes directly, the piezo sounder will emit only a short single beep just as the probes will come in contact with a good junction, due to the time delay provided by the discharge of C2 when the voltage at pin #3 is falling from about 4.1V to 0.3V.
To provide a better signaling system, Fet Q1, IC1B and related components were added. This op-amp is wired as a 1Hz square wave generator and Q1 acts as a solid-state switch, going on and off one time per second having the Gate driven by the op-amp output. In this way, the junction of the device under test is connected and disconnected to the voltage sensitive circuit built around IC1A one time per second and the result will be a clearly audible train of short beeps signaling the good condition of the junction or track under test.

Testing directions:

NPN Silicon Transistors:: Place the Red probe on the Base and the Black probe on the Emitter: a train of short beeps should be heard. If not, the junction is broken or the transistor is a PNP type.; Always holding the Red probe on the Base, shift the Black probe to the Collector: a train of short beeps should be heard. If not, the junction is broken or the transistor is a PNP type.; Placing the Red probe on the Emitter and the Black probe on the Collector should cause no output from the piezo sounder: the same should occur when reversing the probes. On the contrary, if an almost continuous beep is heard, the transistor is dead.

PNP Silicon Transistors:: Place the Black probe on the Base and the Red probe on the Emitter: a train of short beeps should be heard. If not, the junction is broken or the transistor is a NPN type.; Always holding the Black probe on the Base, shift the Red probe to the Collector: a train of short beeps should be heard. If not, the junction is broken or the transistor is a NPN type.; Placing the Red probe on the Emitter and the Black probe on the Collector should cause no output from the piezo sounder: the same should occur when reversing the probes. On the contrary, if an almost continuous beep is heard, the transistor is dead.

Darlington Transistors:: The procedure is similar to that adopted for common transistor types. The main difference is that when testing the Base - Emitter junction, you will hear the train of short beeps even after reversing the probes. This occurs because a couple of resistors is always present across either junction of the two internal transistors forming a Darlington device.; The second difference is due to the fact that an internal diode connected across Emitter and Collector (Anode to Emitter and Cathode to Collector) is always present in these devices. Therefore, with a NPN device, placing the Red probe on the Emitter and the Black probe on the Collector you will hear the usual train of short beeps, but when the probes are reverted there will be no output from the piezo sounder. On the contrary, if an almost continuous beep is heard, the transistor is dead.; PNP devices of this type are tested reversing the probes, as explained above for common transistors.; Please note that when testing the Base - Emitter junction the beeps will be shorter compared to common transistors. This is caused by the fact that two junctions in series are to be measured when testing Darlingtons.

FETs: The testing procedure is the same as that adopted for NPN silicon transistors (N-Channel FETs) or PNP silicon transistors (P-Channel FETs).; The only difference is shown when checking Source - Drain connections (corresponding to Emitter - Collector): a faint, blurring sound will be heard if the device is good, even reversing the probes.

MosFets: These devices cannot be thoroughly tested with this tool, but a MosFet in good condition should cause no beep to be heard when testing all junctions as explained above for common transistors. But the usual train of beeps will be emitted when checking the Source - Drain connection, placing the Red probe on the Source and the Black probe on the Drain of a N - Channel device, because the presence of an internal diode, as explained above for Darlington transistors.

Germanium Transistors: Use the same testing procedure adopted for silicon transistors. The beeps forming the train will last longer than when testing silicon devices: this is due to the lower junction resistance of germanium devices in respect to silicon types.

Silicon Diodes: Place the Red probe on the Anode and the Black probe on the Cathode: a train of short beeps should be heard.; Reversing the probes no beep will be emitted.

Schottky Barrier Diodes: The same as above, but the beeps should last longer.

Germanium Diodes: The same as for Schottky Barrier Diodes.

SCRs and TRIACs: These devices cannot be tested thoroughly, unless they are shorted: in this case an almost continuous beep will be heard.; But this circuit can be useful to distinguish a SCR from a TRIAC.; Placing a probe on the Gate and the other probe on the Cathode or, more properly, the MT1 pin of a TRIAC, the Tester will emit the usual train of beeps, even reversing the probes.; When testing a SCR, the train of beeps will occur when the probes are placed in one way and not when reversed.

Circuit Board Tester

2009-03-04T06:36:00.000-08:00

Indicates the basic integrity of a printed board

Self-powered - 3 to 30V range

Parts:

R1,R2___________22K  1/4W Resistors

D1______________LED  (Any dimension and shape, preferably red)
D2______________LED  (Any dimension and shape, preferably green)

Q1____________BF245 or 2N3819 General-purpose N-Channel FET
Q2____________BC547   45V 100mA NPN Transistor
Q3____________BC557   45V 100mA PNP Transistor

Probe_________Metal Probe 3 to 5 cm. long

Two Miniature Crocodile Clips (Red and Black)

Comments:

This little circuit indicates the basic integrity of a printed board, detecting 0V, positive supply voltage from less than 3V to 30V and floating parts.
If the probe is floating, as it would be in a broken track, then both LEDs barely light up, since there is no current to drive the transistors, but if the probe touches 0V or a positive voltage one or other lights. A digital signal should light them in proportion to the mark-space ratio whereas the output of a circuit oscillating at a frequency rate below about 20Hz will cause the LEDs to flicker alternatively.
The LEDs will illuminate always at a constant intensity, no matter the voltage supply used, because they are fed by a very simple Fet constant-current generator (Q1).

Note:

The Black clip must be connected to the negative ground of the board under test.
The Red clip should be connected to a positive voltage source (not exceeding 30V) available on the same board.

Long delay Timer

2009-03-04T06:35:00.000-08:00

Suitable for battery-operated devices

Fixed 35 minutes delay

Parts:

R1______________10M  1/4W Resistor
R2_______________4K7 1/4W Resistor
R3_______________1K  1/4W Resistor (Optional, see Text)

C1_____________220µF  25V Electrolytic capacitor

D1______________LED   any type and color (Optional, see Text)
D2___________1N4148   75V 150mA Diode (Optional, see Text)

IC1____________4011 Quad 2 Input NAND Gate CMos IC (See Notes)

Q1____________BC337   45V 800mA NPN Transistor

P1,P2__________SPST Pushbuttons

RL1___________Relay with SPDT 2A @ 230V switch (Optional, see Text)
             Coil Voltage 12V - Coil resistance 200-300 Ohm

Device purpose:

This timer was designed mainly to switch off a portable radio after some time: in this way, one can fall asleep on the sand or on a hammock, resting assured that the receiver will switch off automatically after some time, saving battery costs.

Circuit operation:

R1 and C1 provide a very long time constant. When P2 is momentarily closed, C1 discharges and the near zero voltage at its positive lead is applied to the high impedance inputs of the four gates of IC1 wired in parallel. The four paralleled gate outputs of the IC go therefore to the high state and the battery voltage is available at Q1 Emitter.
When P2 is released, C1 starts charging slowly through R1 and when the voltage at its positive lead has reached about half the battery voltage, the IC gate outputs fall to zero, stopping Q1.
This transistor can directly drive a portable radio receiver or different devices drawing a current up to about 250mA. Connecting a Relay across the Emitter of Q1 and negative ground, devices requiring much higher voltage and current operation can be driven through its contacts.

Pushing on P2 for 1 to 5 seconds, the circuit starts and then will switch off after about 35 minutes. This time delay can be varied by changing R1 and/or C1 values. P1 will stop the timer if required.
LED D1 is optional and can be useful to signal relay operation when the load is placed far from the timer.

Notes:

A 4011 Quad 2 Input NAND Gate was used for IC1, but many other CMos gates or inverter arrays can be used in its place, e.g. 4001, 4002, 4025, 4012, 4023, 4049, 4069. With these devices, all inputs must be tied together and also all outputs, as shown in the Circuit diagram.
The operating voltage of this circuit should lie in the 6 - 12V range.

Rotating & Flashing 230V Lights

2009-03-04T06:29:00.000-08:00

Three channels - Three operating modes

Completely ac-insulated circuit board

Parts:


R1,R2,R3,R5____470K  1/2W Trimmers Cermet or Carbon (See Notes)
R4______________10K  1/4W Resistor
R6,R7,R8_________1K  1/4W Resistors
R9_____________120R  1/2W Resistor
R10,R12.R14______1K  1/2W Resistors
R11,R13,R15______1K  1/4W Resistors


C1,C2,C3_________1µF  63V Polyester or Electrolytic Capacitors
C4______________10µF  25V Electrolytic Capacitor
C5_____________100µF  25V Electrolytic Capacitor
C6____________1000µF  25V Electrolytic Capacitor

D1,D2,D3_____1N4148   75V 150mA Diodes
D4_________BZX79C15   15V 500mW Zener Diode
D5,D6________1N4002  100V 1A Diodes
D7,D8,D9____TIC206M  600V 4A TRIACs (See Notes)

Q1____________BC547   45V 100mA NPN Transistor

IC1____________4093  Quad 2 input Schmitt NAND Gate IC
IC2-IC4_____MOC3020  6-Pin DIP Optoisolators, Triac Driver Output

P1_____________SPST Pushbutton
SW1____________2 poles 3 ways Rotary, Slide or Toggle Switch
SW2____________SPST Toggle Switch 250V 10-15A (See Notes)

T1_____________220V Primary, 24V center tapped Secondary 3VA Mains Transformer

PL1____________Male Mains Plug

SK1,SK2,SK3____Female Mains Sockets

Circuit operation:

This design can be of some interest for those wanting striking light signs, as it can drive up to three 230V lamp strings in three operating modes.
The 15V dc supply is obtained from a nominal 230/24V center tapped ac transformer (T1) and a full wave rectifier (D5 & D6): Zener diode D4 was added to clamp the dc voltage to 15V maximum.
Triacs D7, D8 and D9 are insulated from the control circuitry by means of Optoisolators IC2, IC3 and IC4. IC1A, B and C are wired as monostables and cascaded in order to obtain a rotating sequence when the Mode switch SW1 is set in the Rotate position.
IC1D acts as an astable multivibrator and generates an adjustable flashlight, driving all three lamp strings at the same time when the Mode switch SW1 is set in the Flash position.
The All On operating mode allows all lamps to be on at the same time and can be used either for general illumination or to single out a blown bulb.
Each channel can drive several 230V lamps wired in parallel for each string, provided the maximum current of the Triacs is not exceeded. For example, each channel will be able to drive up to 20 40W bulbs.
The circuit is also well suited for many small bulbs wired in series like the usual Christmas tree lamp strings decorations. As these are very low power devices, a lot of them can be driven by this circuit. The more lamps per string are used, the more satisfactory will be the resulting effect.

Notes:

A brief push on P1 will be necessary to start the Rotate operation mode.
The Trimmers R1, R2 and R3 should be adjusted to obtain equal delay times or until a pleasing visual result is obtained when observed from some distance. In any case, the Trimmers can be substituted by three fixed 1/4W resistors of equal value: 100K, 220K or 470K will work fine.
On Flashing operation mode, adjust R5 until the best effect is obtained.
The Triac types suggested are not mandatory: you can use more powerful devices with no circuit change.
SW2 must be a high voltage, high current switch, as it must withstand the total amount of current drawn by all bulbs.

Dual-rail Variable DC Power Supply

2009-03-04T06:28:00.000-08:00

Simple add-on for a single-rail supply

±2.5V to ±15V output

Parts:

R1,R2____________4K7 1/2W 1% or 2% Metal Oxide Resistors


C1,C4,C5_______100nF  63V Polyester Capacitors
C2,C3__________220µF  25V Electrolytic Capacitors

Q1____________BD437   45V 4A NPN Transistor
Q2____________BD438   45V 4A PNP Transistor

IC1___________LM358   Low Power Dual Op-amp

Input and output connecting terminals etc.

Comments:

This design was conceived as an add-on for the Variable DC Power Supply, a very successful circuit posted to this website in the year 2000.
This simple unit provides a dual-rail variable output ranging from ±2.5V to ±15Vdc with precise tracking of the positive and negative output voltages, still retaining the current limiting and short-proof capabilities of the "master" circuit.
As the purpose of such a dual-rail design is to supply experimental or under-repair circuits, the maximum current output delivered was deliberately kept to about 500 - 600mA per rail, thus avoiding the use of expensive power transistors and complex circuitry.

Notes:

The circuit can be placed into the existing Variable DC Power Supply metal cabinet.
Q1 and Q2 must be mounted on heatsinks. Usually, bolting them to the metal case (through insulating washers etc.) proved effective.
The full ±15V output can be achieved only if the secondary winding of the supply Transformer used in the Variable DC Power Supply is rated at 48V minimum (center tapped).
When using this circuit, please set the Current-limit control (P1) of the Variable DC Power Supply to any value comprised in the 50mA - 1A range but not higher.
The second Op-amp (IC1B) contained in the LM358 chip was not used, but its input pins were tied to the negative supply and the output was left open.

Electronic Candle Blow Out

2009-03-04T06:27:00.000-08:00

LED or bulb switch off with a puff

Funny gadget - 3V Battery supply

Parts:

R1______________10K  1/4W Resistor
R2_______________1M  1/4W Resistor
R3_______________1K  1/4W Resistor
R4_______________4K7 1/4W Resistor (See Notes)
R5______________10K  1/4W Resistor (See Notes)
R6_____________100R  1/4W Resistor (See Notes)

C1_____________100pF  63V Ceramic Capacitor
C2______________10µF  25V Electrolytic Capacitor
C3_____________100nF  63V Polyester or Ceramic Capacitor

D1___________1N4148   75V 150mA Diode
D2______________LED (Any suitable type)

Q1____________BC550C  45V 100mA Low noise High gain NPN Transistor
Q2____________BC337   45V 800mA NPN Transistor
Q3____________BC327   45V 800mA PNP Transistor

MIC1__________Miniature electret microphone

P1_____________SPST Pushbutton Switch

B1_______________3V Battery (2 x 1.5V AA, AAA Cells in series etc.)

Comments:

This design was developed by request of a correspondent having made a sort of LED candle and needing to switch off the LED with a puff.
This simple, easy to build gadget can be useful as a prop for Halloween and Christmas season, shows and the like.
Q2 & Q3 form a self-latching pair that start operating when P1 is pushed: in this way the LED (or bulb) will illuminate steadily. When someone emits a strong puff in the vicinity of the small electret microphone, the resulting signal will be greatly amplified by Q1 and a rather long positive pulse (shaped by D1 and C2) will reset the self latching pair through the Emitter of Q2.
The very low (and unusual) value of C1 acts as a simple high-pass filter, in order to prevent that normal speech or environmental noise shut off the device. Obviously, such a simple filter cannot be very discriminating, therefore, not only a strong puff will reset the circuit but also a loud shout, blow, clap or stroke.

Notes:

A small bulb can be used in place of the LED. In this case a 3 - 3.5V, 0.7W (200mA) incandescent bulb can be used satisfactorily. Therefore, D2, R5 and R6 must be omitted, the bulb wired in place of R5 and R4 value changed to 1K5.
Using a bulb instead of the LED, a 1.5V battery supply could also be used. A 1.5V, 0.3A incandescent bulb will work, but R4 must be replaced by a 470 Ohm Trimmer, adjusted to allow a reliable circuit operation.
Please note that the circuit will draw a small current even when the LED or bulb are off. This current is about 1.2mA for the LED version of the circuit, 1.5mA for the 3V bulb version and 1mA for the 1.5V bulb version. Therefore, in some circumstances, the addition of a power on-off switch could be necessary.

One second Audible Clock

2009-03-04T06:26:00.001-08:00

Accurate, finger-operated portable unit

3 - 12V Battery supply

Parts:

R1______________10K  1/4W Resistor
R2_______________4K7 1/4W Resistor
R3_____________100R  1/4W Resistor (Optional, see Notes)

C1_______________1nF  63V Polyester or ceramic Capacitor
C2______________10µF  25V Electrolytic Capacitor
C3_____________100nF  63V Polyester or ceramic Capacitor (Optional, see Notes)

D1,D2,D3_____1N4148   75V 150mA Diodes
D4______________LED   (Optional, any shape and color, see Notes)
D5___________1N4148   75V 150mA Diode (Optional, see Notes)

Q1____________BC337   45V 800mA NPN Transistor

IC1____________4024   7 stage ripple counter IC

BZ1___________Piezo sounder (incorporating 3KHz oscillator)

SPKR______________8 Ohm, 40 - 50mm diameter Loudspeaker (Optional, see Notes)

SW1____________SPST Toggle or Slide Switch (Optional, see Notes)e

B1________________3 to 12V Battery (See Notes)

Comments:

This accurate one-pulse-per-second clock is made with a few common parts and driven from a 50 or 60 Hertz mains supply but with no direct connection to it.
A beep or metronome-like click and/or a visible flash, will beat the one-second time and can be useful in many applications in which some sort of time-delay counting in seconds is desirable.
The circuit is formed by a CMos 4024 counter/divider chip and 3 diodes, arranged to divide the frequency of the input signal at pin #1 by 50 (or 60, see Notes).
The input impedance at pin #1 is very hight, so simply touching the pin (or a short track or piece of wire connected to it) is usually enough to provide the necessary input signal.
Another way to provide an input signal consists in a piece of wire wrapped several times around any convenient mains cable or transformer. No other connection is necessary.

Notes:

To allow precise circuit operation in places where the mains supply frequency is rated at 60Hz, the circuit must be modified as follows: disconnect the Cathode of D1 from pin #11 of IC1 and connect it to pin #9. Add a further 1N4148 diode, connecting its Anode to R1 and the Cathode to pin #6 of IC1: that's all!
The circuit will work fine with battery voltages in the 3 -12V range.
The visual display, formed by D4 and R3 is optional. Please note that R3 value shown in the Parts list is suited to low battery voltages. If 9V or higher voltages are used, change its value to 1K.
If a metronome-like click is needed, R2 and BZ1 must be omitted and substituted by the circuit shown enclosed in dashed lines, right-side of the diagram.
Stand-by current drawing is negligible, so SW1 can be omitted.

Cricket Chirping Generator

2009-03-04T06:24:00.000-08:00

Funny gadget for props and jokes

5 - 12V Battery operation

Parts:

R1_____________330K  1/4W Resistor
R2_____________220K  1/4W Resistor
R3,R6__________100K  1/4W Resistors
R4_____________Photo resistor (any type) (Optional, see text)
R5,R7___________22K  1/4W Resistors
R8______________10K  1/4W Resistor
R9_____________470R  1/2W Trimmer Cermet or Carbon
R10_____________22R  1/4W Resistor

C1,C2,C3________47µF  25V Electrolytic Capacitors
C4______________10µF  25V Electrolytic Capacitor
C5_______________1µF  50V Electrolytic Capacitor
C6______________10nF  63V Polyester Capacitor

D1,D2,D3,D4__1N4148   75V 150mA Diodes

Q1____________BC547   45V 100mA NPN Transistor

IC1____________4093   Quad 2 input Schmitt NAND Gate IC
IC2____________4060   14 stage ripple counter and oscillator IC

SPKR______________8 Ohm Small Loudspeaker

SW1____________SPST Toggle or Slide Switch

B1_______________9V  PP3 Battery (See Notes)

Clip for PP3 Battery

Comments:

This circuit generates an astonishingly real imitation of the chirping of the cricket. A suitable audio wave form is generated by IC2 and related components, driving the loudspeaker through Q1.
To allow a more real-life behavior, the chirp is interrupted in a pseudo-casual way by two timers built around IC1C and IC1D, whose outputs are mixed into IC1B and further time-delayed by IC1A, driving the reset pin of IC2.
An optional Photo resistor can be wired across this pin and positive supply, allowing circuit starting in the dark and stopping when light is coming, thus imitating the cricket's behavior even more closely.
R9 acts as volume control and can be a preset trimmer or a small potentiometer.

Notes:

The circuit can be powered by any battery voltage in the 5 - 12V range.
For optimum results please use a loudspeaker as small as possible.
In some cases, the chirp can be improved further on by pressing the loudspeaker against a flat surface, e.g. a wooden table.

Programmable LED Flashers

2009-03-04T06:23:00.000-08:00

LED changing to steady state after a preset number of flashes

Two simple, wide supply range operating circuits

Circuit diagram #1:

Parts:

R1______________10K  1/4W Resistor
R2_______________1M  1/4W Resistor
R3_______________1K  1/4W Resistor (See Notes)

C1_______________4µ7  25V Electrolytic Capacitor
C2______________10nF  63V Polyester Capacitor

D1___________1N4148   75V 150mA Diode
D2______________LED (Any dimension, shape or color)

IC1____________4060  14 stage ripple counter and oscillator IC

P1_____________SPST  Pushbutton
SW1____________SPST  Toggle or Slider Switch

B1______________3V to 15V Battery or dc power source (See Notes)

Circuit diagram #2:

Parts:

R1_____________100K  1/4W Resistor
R2_______________1K  1/4W Resistor (See Notes)
R3______________10K  1/4W Resistor

C1,C2____________4µ7  25V Electrolytic Capacitors

D1___________1N4148   75V 150mA Diode
D2______________LED (Any dimension, shape or color)

IC1____________7555 or TS555CN CMos Timer IC
IC3____________4017  Decade counter with 10 decoded outputs IC

SW1____________1 pole 9 ways Rotary Switch (Optional)
SW2____________SPST  Toggle or Slider Switch

B1______________3V to 15V Battery or dc power source (See Notes)

Comments:

These circuits were designed on request. Both feature a flashing LED that, after a preset number of flashes will illuminate steadily until P1 (Reset) will be pressed.

Circuit #1 uses only one chip and can be useful if a not very precise number of flashes of the LED is needed before reverting to the steady-on state. In fact, connecting D1 Anode to different output pins of the IC, the steady-on state of the LED will be obtained after 2, 4, 8, 16 flashes and so on.
Connecting D1 Anode as shown, the LED will start flashing at about two times per second after power-on and will revert to the steady state after 8 flashes. P1 resets the circuit and C1 automatically resets IC at power-on.
Connecting D1 Anode to pin #13 of IC1 the flashes will be 4; to pin #1 will be 16 etc.
The flashing frequency of the LED can be varied by changing the values of R2 and/or C2.

Circuit #2 is more precise and uses about the same parts count of Circuit #1, though requiring two ICs. By choosing the appropriate output pin of IC2, the steady-on state of the LED will be obtained after 1 to 9 flashes, as shown in the drawing at SW1 pins. This switch is optional, as D1 Anode can be hard wired directly to the required output pin of IC2. P1 will work as in Circuit #1 but with some difference: after a momentarily press the LED will restart to flash, but the total number of flashes will be one less than obtained after power-on. Furthermore, if P1 is closed permanently, the circuit will flash permanently.
The flashing frequency of the LED can be varied by changing R1 and/or C1 values.

Notes:

Circuits were tested at 9V supply, but they might work in the 3 - 15V dc supply range.
The LED current limiting resistor value was calculated for 9 - 12V supply and should be changed to suit different supply voltages.

R1, R2	10KOhm
R3	47Ohm
C1, C2	1nF
C3	4,7uF/16V
C4, C7, C8	0~45pF trimmer
C5, C6	10pF
C9	100nF
L1	4 turns, 7mm diameter *
L3	3 turns, 7mm diameter *
L4	5 turns, 7mm diameter *
L2	RFC (resistance 1MOhm with wrapped around her inductor of enough coils from fine isolated wire. Scratch of utmost inductor and you stick in utmost the resistance making thus a parallel L-r circuit.)
T1, T2	2N2219
ANT	Simple dipole l/2.
MIC IN	Microphone dynamic or other type. (It can also connected to a cassette player unit)