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Testing IR Leds

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mattg2k4

New Member
Are there any readily available materials that will light up under IR for quick verification of whether an IR led is working? I know I could set up a circuit with a phototransistor, but I'd like to see if this would be a viable method first.
 

Nigel Goodwin

Super Moderator
Most Helpful Member
mattg2k4 said:
Are there any readily available materials that will light up under IR for quick verification of whether an IR led is working? I know I could set up a circuit with a phototransistor, but I'd like to see if this would be a viable method first.

If you look at it through a cam-corder or digital camera, you will see it as lighting up white - this has been commonly used for years to check remote controls. You can also buy a small 'card', I've no idea how they work, but they appear to have a coating which absorbs the IR and gives off visible light - these are sold in the TV trade for testing remotes.

Personally I now use an IR Remote tester I built myself, but it probably wouldn't be of help to you, as it requires 38KHz modulation (as used by IR remotes) - it wouldn't detect an unmodulated IR LED.

You could also simply measure the current through it, and the voltage across it, these would give a good indication if it was working or not.
 

crust

Member
I have a little card that I use for a UV laser. I hold it up in the beam and it glows bright orange. I know that there was also an IR card that was maybe $3 USD or so (the UV one was ~$100 USD).

in fact here is one
 

McGuinn

New Member
I have used cameras for testing for quite a while, but I notice that some of the newer ones are not sensative to IR any more. IR affects photos taken in direct sun-light, and reducing a camera's sensitivity to IR is seen as the way forward... apparently.
 

mattg2k4

New Member
Well I just tried my digital camera, and its completely blind to my IR led.

Know where I can pick up one of those IR sensitive cards?
 

mozikluv

New Member
testing ir

:D

how about using a simple am transistor radio, just set your dial to the 38khz band. :D
 

bmcculla

New Member
All Digital camera detectors will detect IR. The problem is that high quality cameras have a IR filter that removes IR. Get a cheap webcam or better yet a pinhole cam that has no filtering at all.

www.cyberguys.com has a little webcam for $9.95. Part Number 2040582.

Brent
 

mattg2k4

New Member
I do have an old USB camera I'd completely forgotten about. It picks up the IR leds just fine, thanks for the suggestions!
 
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