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Author Topic: Want to reuse "learning" remote control's IR LED  (Read 1592 times)

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Offline corrado33Topic starter

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Want to reuse "learning" remote control's IR LED
« on: April 21, 2010, 08:07:10 PM »
So I have a learning remote control that doesn't work that well anymore.  I want to use the IR LED in it to act as an IR receiver, then use another IR led to act as a emitter.  Yep, you got it, I'm trying to build an IR range finder (more like an IR wall detector).  Anyone know anything about Learning remote control IR LEDs?

Yes I will eventually buy IR rangefinders for my bot, but for now, I have no money, and I want to see if I can figure this one out.

EDIT:  If you don't know what a learning remote control does... well, you push a learn button, then use another remote control to emit the frequency you want, then whatever button you tell the learning remote to use that frequency for, it will. 
« Last Edit: April 21, 2010, 08:11:27 PM by corrado33 »

Offline Razor Concepts

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Re: Want to reuse "learning" remote control's IR LED
« Reply #1 on: April 21, 2010, 08:41:38 PM »
Those LEDs are normal IR leds  :)

They can be configured to sense IR light - search for LED as a light sensor.

Offline corrado33Topic starter

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Re: Want to reuse "learning" remote control's IR LED
« Reply #2 on: April 21, 2010, 08:48:11 PM »
Those LEDs are normal IR leds  :)

They can be configured to sense IR light - search for LED as a light sensor.


Yeah I've seen that done before, and in fact I was doing that a few seconds ago.  I saw this video...
LEDs as sensors!


and if you look in the description it says the leds are switched from forward bias (normal hookup i think), reverse bias (acts as capacitor) and discharging (??????)  I'm not sure what that last state is?  Is that when you'd measure the voltage?

Offline Razor Concepts

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Re: Want to reuse "learning" remote control's IR LED
« Reply #3 on: April 21, 2010, 10:08:03 PM »
I actually made it to a state science fair with this kind of stuff  :)
Basically, reverse voltage the LED for 1 microsecond, end the reverse voltage, and measure the voltage coming out of the LED(from its capacitance), and time the time it takes to reach a certain point. That time varies depending on the incoming light.

See:
http://www.merl.com/projects/LEDcomm/

 


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