Introduction: Interactive LED Table - the Simple Way
Ok so how many of you have seen the interactive tables that can sell for over $150 a square foot? So you look around try to put together some figures on it then realize its just too expensive. If only there was a cheap simple way... say something with 1000 LEDs maybe like a 24 x 48 table, yeah now thats nice, but how bout under $50 for the whole thing? Na thats gotta be impossible. . . or is it? Yes it is possible just by following this simpe instructable. If you can solder, use a hot glue gun, drill, and be smooth at your local drug store then it is very possible. So without further adue here it is.
P.S If you attempt this I am not responsible for any damages to your self or any of your property. THIS 'IBLE WILL INVOLVE HIGH ELECTRICTY, HOT MATERIALS, AND SEVERE MENTAL STRESS, ok maybe not the last one, but it is very dangerous if you attempt it without prior knowledge of electricity.
Step 1: Gather Materials
Ok so first you will need some supplies.
1. Solder and soldering iron.
2. Hotglue and a hotglue gun.
3. leds of your choice, the color and count is up to you, but ordeing in 1000's is the cheapest, ebay is the best source.
4. A high voltage power supply, i.e. Disposable camera, if you visit your local drug store they will most likely give you used ones for free.
5. Peg board, homedepot is very good for this a 24 x 48 sheet is $6.
6. IR LEDs, order a certain quantity depending on how big you want you table to be. 4 per 12 x 12 square is usually good.
7. IR sensors, here is a link to digikey they have the best prices. http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=475-1081-ND We will discuss this later.
1. Electric tester capable of 300 volts.
2. A TIP31 Transistor.
3. A speaker set.
4. A heaphone splitter. i.e. 1 male to 2 female headphone plugs.
Step 2: Board Assembly
Ok now you have the daunting task of soldering 1000+ LEDs. So heres how to start, gather your blue and IR LEDs, make sure to keep them seperate, now take each one and bend the leads at a 90 degree angle to the base then bend them upward halfway to the end of the lead as shown. You can do this ahead of time or while your building. After that lay out your battle strategy on the back of the board, you want to make designs that fit together having about 90 LEDs per segment. Or you can do some math to figure out how many you could run off 300~314v depending on how much each draws. Simply divide 300 by the voltage of each LED, then its time to pillage the village. (Also to keep this simple and cheap I won't use resistors for them, although if you have the time it is highly recommended if you google resistor calculator you can try to figure out how big the resistor needs to be I never got the hang of how to do that). So with running 90 per segment they are quite bright, almost hard to look at. Also this board will be run in series so lay your LEDs into place having the positive lead start (usually the longer one) then have the positive lead of the next LED connect to the negative on the previous LED, as for connecting the rows there is an example in the pictures. (Google will give you a better picture of whats going on just search "LEDs in series.") Do this usually a few rows at a time then glue them, while the glue is soft flip it up and try to straiten any ones that have drifted off center, this is why you only do a few at a time it gives you time to move them.
Step 3: Wiring the LEDs.
Now you get to wire all those LEDs, Soldering is best left until a segment is completed, you will want a good hot soldering iron, battery operated ones can't really stay hot for fast easy soldering, if your are familliar with irons you will notice the solder flows much better with a very hot plug in iron rater than a quick and small cordless one, I have both and side by side there is a huge difference. So back on track, you can then fold the leads down and let them overlap as shown and then just quickly touch a bit of solder to the iron and connect the leads. Once you get the hang of it, it will take the longest to un-roll your solder to keep going. After that you just have to to wire the sensors and the power supply.
For the IR lights you want to drill seperate holes in the board to put them through, then just wire them in parallel to a neighboring LED I didn't get to do this because the IR LEDs didn't show up in time.
Step 4: Wiring the Sensors
This is the best part of the 'ible NO MICRO PROCESSORS!!! The simplest way is to wire the sensors from the materials page to the leds, as for the discussion a carefull viewer would notice that the max voltage on the website says 70v but it can go higher... much higer say like 300. It sounds dangerous but they show no signs of stress or heating during operation. You will want to drill a hole through the board in the center of each segment, it is best to drill from the front that way you get a nice clean hole on the front, ( I neglected to do that) Then the shorter lead is the voltage input and the longer lead is the voltage output meaning it allows voltage to pass out of the longer lead when hit with IR light. (and I have no clue how it works but if someone would care to explain I would be happy to listen.) You want the sensor to interrupt the positive voltage, so wire from the positive lead on the camera to the sensor input lead then from the output sensor lead to the positive lead on the LED segment. Then wire from the negative lead on the LED segment to the negative lead on the camera. There is an example in the photos. You will also want to be sure not to touch any of the leads together and be sure to flash the camera by spinning the little gear just above the film window then push the small white lever forward (on this model it is seen just below the images remaining wheel. Or push the shutter button on top if you have one. Then use a rubber handled screw driver to short the leads of the capacitor, be carefull sparks will fly and don't touch any other leads together except the 2 capacitor leads. Then solder the flash button together so it is permanently on.
Step 5: Powering Up.
Now you can choose to wire each camera to its own segment or you can wire up to 4 segments together but I wouldn't want to go over 4 due to the draw on the camera. Insert the battery into the cameras and listen for the tell tale sound of a capictor charging up. When the voltage gets high enough they will fade on even in normal light or no light because of random IR light being emmited by devices. Then either wave your hand over it, (if using built in IR LEDs) or point a IR source at it such as a single IR light, a night vision camera or an IR Remote control for a tv and watch the magic of simplicity. (Also lasers, and other lights will activate it.)
Step 6: Wrap Up.
So you now have a fully functional $180 commercial panel for under $50. Videos are also here.
Also instead of a second part I've decided to do a whole new instructables so here is a link to that one as well.
Please feel free to express your thoughts and opinions freely here or at the beginning. Happy instructable-ing, everyone!
Also the main reason for this instructable is for the Epilog Laser challenge I would love to be able to manufacture parts to create more 'ibles and other great projects, or maybe even market some of my other ideas.