Hi

I want to build a IR array for the VR experiments; where the Wiimote tracks IR from the reflective tapes paste on the fingers.

I've got a few questions:

1. How many IR LEDs are required?
I want to use if on everything from a laptop screen, PC LCD screen to a projection TV, and LCD TV

2. Do you know the exact wavelength of the IR that wiimote is sensitive?
I recently bought a bunch of IR LEDs that emit a detectable red glow when powered. These are unlike some IR LED I had earlier that has no detectable output seen by the naked eye. I find that the wiimote is less sensitive to the new batch of IR LED that emit the red glow.

3. Do i need a large spread angle?
Do I need to flood that whole area with IR or just a small angle will do?

Thanks and hope to hear some input.

Cheers!

Aaaand I want answers to these exact questions too! I'm surfing for specs...

I worked extremely hard with the IR array to get it to work and (you can see all my <a href="http://www.designerwpf.com/2008/02/29/the-trials-and-travails-of-the-infrared-multipoint/#comment-924">attempts over here</a>). I couldn't get the IR Array/reflective tape combo to work at all. This was after using a 96 LED infrared array. I tried it with two different kinds of reflective tape (which can be really expensive) and finally I got an 1,000,000 candlepower IR spotlight. All in all, I spent almost $200 trying different things.

Take my advice, save yourself a bunch of time and money and do what I did... I ended up building some gloves with the same IR LEDs I used to create the array placed on the fingertips. (The LEDs were 1.2-1.3V, 100mA and 940nm wavelength with a 30 degree spread.) That worked like a dream (<a href="http://www.designerwpf.com/2008/03/10/mix-08-wpfwiimote-show-off-video/">video here</a>). I bought some $10 gardening gloves, 4 IR LEDs from Radio Shack, some resistors, some thin wire, electrical tape, two <a href="http://www.radioshack.com/product/index.jsp?productId=2062571">blinking LED modules</a> and some sew-on/stick-on velcro ($10/yard at any craft store).

I clipped off the visible LED from the blinking LED module, wove the thin wire through the fabric of the gloves to hold it down, soldered it to the IR LEDs at the fore-finger and thumb (using electrical tape to hold it in place) and then to the loose wires on the LED module, stuck one side of the velcro onto the battery pack of the LED Module and sewed the other side of the velcro to the wrist of my glove. Works great.

I'm planning on improving the design with 3 LEDs per finger to make them really bright and therefore visible from a greater distance and less finicky. But the whole thing is about a $20 per set of gloves and was alot less painful than the IR array (which I still have never been able to get to work.

Hope that helps!

two things:

first try to increase the sensitivity of the wiimote by altering the source code:

instead of
next try stronger LEDs, if you buy them, have a look at the mW/sr numbers.
higher is better, I would recommend 100 or more
these ones are pretty decent and affordable (<1€ each), the multitouch guys use these as well for their projects

http://www.multitouch.nl/pdf/osramled.pdf

tell me if that helped!