Gun4IR - 4 IR points must be detected - tried 2x Camera Moudles so far

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m1n10n:

--- Quote from: RandyT on May 21, 2024, 02:27:58 pm ---I'll second that. Unless there is an IR blocking filter on the camera being used, those LEDs should be bright and nearly white.

OP: Bridging LEDs is typically a bad idea, depending on the circuit. But given the low output (unless they are already destroyed) they might still be ok.

What voltage are these running at and how are they wired? At the typical 1.7 to 1.8v, three of them in series on 5v would need 1ohm or less (really 0, as there is barely enough to light them up). 2 in series is ~75ohm, or twice what you have. Keep in mind that once you step over the ratings, output will decrease and the LED is immediately damaged irreparably. Changing things without understanding the circuit and the specs of the parts in it, is a recipe for disaster.

--- End quote ---

Interesting - yeah ... this is why I started jumping them one at a time and watching the brightness of just one increase ... Seems this is not the best way to do this?

RandyT:
I'm still not convinced that 940nm is the best wavelength for these, but to each their own on that front.

The video indicated a 27ohm resistor, not 37. However, 37ohm would have put the per-LED forward voltage at a conservative ~1.4v, so that shouldn't have been terrible, based on the stated specs.

On the other hand, it's difficult to know what those are based upon. Sometimes the Chinese sellers will spec these with a range, with the lowest value being the moment they begin to emit, which is not very useful, but easy to test. The real question is what the higher value in the range is based upon, sans a proper datasheet with testing charts. It may be that they are intended to operate at the max of 1.5v, which is what that 27ohm resistor will provide.

Now the issue you have is that you attached different power supplies. At 6v, with the 37ohm resistor, you fed the LEDs double what they are rated for. While they may not be completely dead, I am 99.9% convinced that they are severely damaged, and not emitting what they should after that. If you went higher, then change that to 100 :)

What I would do at this point is rebuild the circuit with new LEDs AND a 27ohm resistor AND use a 5v supply. All 4 of the modules should be running in parallel off of the supply. But if for some reason you have the modules in series, that will never work.

If that doesn't work for you, you will likely need to look at some different LEDs.

m1n10n:

--- Quote from: RandyT on May 24, 2024, 01:22:35 pm ---I'm still not convinced that 940nm is the best wavelength for these, but to each their own on that front.

The video indicated a 27ohm resistor, not 37. However, 37ohm would have put the per-LED forward voltage at a conservative ~1.4v, so that shouldn't have been terrible, based on the stated specs.

On the other hand, it's difficult to know what those are based upon. Sometimes the Chinese sellers will spec these with a range, with the lowest value being the moment they begin to emit, which is not very useful, but easy to test. The real question is what the higher value in the range is based upon, sans a proper datasheet with testing charts. It may be that they are intended to operate at the max of 1.5v, which is what that 27ohm resistor will provide.

Now the issue you have is that you attached different power supplies. At 6v, with the 37ohm resistor, you fed the LEDs double what they are rated for. While they may not be completely dead, I am 99.9% convinced that they are severely damaged, and not emitting what they should after that. If you went higher, then change that to 100 :)

What I would do at this point is rebuild the circuit with new LEDs AND a 27ohm resistor AND use a 5v supply. All 4 of the modules should be running in parallel off of the supply. But if for some reason you have the modules in series, that will never work.

If that doesn't work for you, you will likely need to look at some different LEDs.

--- End quote ---

Sounds good - thanks for the attention here - hopefully I can go over it all again this weekend and will post findings.

Muhammad Darab:
Hey there m1n10n,
Did you manage to find out what the issue was..?

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