LEDs as input devices

[RoyalScam]

OK Boxers! I won't even pretend that I understand micro controllers at this point, but I'm pretty sure that this may be the next big thing since the lighted push button switch.  I somehow stumbled onto this doc and thought that someone here with better chops than I might find this as fascinating as I did.  I didn't know that an LED in it's reversed biased state can actually be used as a photodiode, according to this doc a device can be made using the LED as both an indicator and input device.

I believe that this is being used in this video;

http://video.google.com/videoplay?docid=-6431755676396318073

And the paper describing the circuit is here;

http://www.merl.com/reports/docs/TR2003-35.pdf

Whaddya think, Sirs?

RoyalScam

[Screaming_Rabbit]

Search the forum, there already is a thread about this. As far as I can remember, the problem was using it in a matrix and scan all the LEDs in a reasonable time.

Greets, Roger

[RoyalScam]

Well, poop.  I should've known it's been seen before.  Nice dream though.  Besides, Forrest Mims was cited in the article and it reminded me of all the great things I learned because of him, back when I was a geeky kid with a Library card.

Scam

[stryd_one]

Search the forum, there already is a thread about this. As far as I can remember, the problem was using it in a matrix and scan all the LEDs in a reasonable time.

that's correct... mind you, it wasn't done in ASM, but in BASIC... so, if someone were to do it properly, and/or perhaps use a certain fancy new 32 micro powered dev board, maybe they would have more luck.... Hypothetically if I were to know someone in that situation I would tell them good luck from you ;) Wink, nudge, etc.

[lucem]

Hypothetically if I were to know someone in that situation I would tell them good luck from you Wink

Hm, to whom may he be referring to with that?  :o

[stryd_one]

I have no idea. *whistle*