Short Circuit??

Ok, well I've been out of physics for 2 years, and I've been out of high-school physics where I probably did this last for 4 years, so I can honestly say that my mind has slipped a lot when it comes to simple circuit design. I'm pretty sure the guy at Radio Shack last night sold me the wrong parts, but that's not too bad only a dollar or two wasted on this endeavor.

What it boils down to is this. Until I can get myself a pair of swanky built in glasses with IR Led's I'm going to need to find a way to get around it. Not owning a wii, I can't even just hold the sensor bar on top my head. So my solution is to build one. I've got all the components I think I need (with perhaps the proper current limiting resistor) and now it's time to crunch the numbers.

My IR LEDs are supposed to run on 1.2 v forward current, and 100mA of current. For the time being I'm looking at running the whole suite off of 3v. Possibly because I think that I can get most watch style batteries in 3 volts and anything less seems very difficult to work with.

So with a little number crunching on my part (and a lot on the internets part) I came up with that with a single strategically positioned resistor I should be able to cause a 1.5v drop across the LED's with the proper current. Somewhere along the way, the internet disagreed. I'm going to run my numbers again tomorrow and see where I went wrong, but I'm almost certain I got it correct. So at the moment with everything wired in series. 3v DC from 2 AA 1 15Ohm resistor and 2 IR LED's we're getting a signal that the Wii can read. We have component 3 in its infancy.

I want to decrease the dispersal on the LED's since we're not trying to light the world. I also want to optimize the intensity on the LED's because I strongly feel that we're running really low on the efficency scale.

There was an interesting idea suggested the other night by the guy at radioshack. Something that bears merit to investigate. He had mentioned that eyes reflect IR (hence Red eye and such) and that it would be possible to leverage that fact to build an eye tracking system. I'm calling in my buddy from Hopkin's who's kept up with this to see if there's any merit in it. After that come the health concerns.