IR LED - Does anyone know the answer??

I posted this before but the problem still exists. Grounding the Cathode did
I have been trying to get an IR LED(transmitter) working with my Basic
Stamp 2. I have wired it up to the BS2 with a 220ohm resistor between the
Cathode and the BS2 pin. I have grounded the Annode. I am using the FREQOUT
function (FREQOUT 6, 1, 37500) on the pin with a frequency of 37500 (I have
tried multiple frequencies > 37500). The IR LED will just not light up (I
have tested with a video camera). I have tried directly wiring the IR LED to
+5v with a 220ohm resistor connected to the Cathode, and Annode to Gnd, but
it still wont light up. I have 3 IR LEDs that I have been testing with, so I
do not think the LED/s is faulty. The circuit lights up without issue with a
standard LED (I have tried multiple 5mm and 3mm LEDs), the IR LED just
simply wont light up.
Does anyone have any ideas?
IR LED specs:
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Many thanks.
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Its just an LED. You don't ground the anode, you ground the cathode. The long pin (anode) goes to 5V. The short pin (cathode) goes to your resistor. The resistor goes to ground.
Note that according to the spec you posted, it has a 5V reverse voltage, so its possible you destroyed them putting them in backwards (although with a resistor and a 5V supply, you should have been safe.) You can also destroy them pretty easily by putting too much current through them. Since the output is invisible, and it happens quickly, you don't know right away (i've done this at least once)
Test the circuit with a visible LED, then replace the IR led and look at it with your camera.
It might also be your basic stamp. Have you ensured that its wiggling the pin? Using a visible LED with a much slower frequency (like 10) would give you a clue as to whether things were working or not.
Regards, Bob Monsen
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Robert C Monsen
I could be wrong, but I don't think that ALL video cameras are IR sensitive.
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Hmm, I have a web cam and it can record when I push a button on the remote control
Reply to
Refik Hadzialic
Best thing to do is first make sure your camera can see IR light, point a remote at it and press a button. Next hook the IR LED directly to your 5V supply (using your current limiting resistor) and see if you can see the light with the camera. If you can at least you now know that the IR LED is working, next connect a visible light LED to the BS2 and see if it even turns on.
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