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What would be the best IR receiver for 980nm IR laser 0-15KHz Answered

Dear enthusiasts, please help me out. What would be the best IR receiver to use for detecting signal from 980nm IR laser 0-15KHz. I'm going for distance here. 200 meters is more or less the goal. The further the better. Ambient light might also be an issue as this is to be done outside in possibly sunny conditions. If anybody has any ideas or suggestions please, throw them out here. Thanks.

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user
Omnivent (author)2017-12-18

Hi,

What kind of signals are you planning?

Do you use a modulated carrier or are you trying to just play an audio signal into the LASER?

You're going to have a hard time aiming an invisible LASER beam ;)

200 meters pfft... you can go more than 1km with IR-LEDs, given the right optics and since they aren't thin coherent beams, they're much easier to align.

Regards

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GusevAnton (author)Omnivent2017-12-18

Hello,

I'm trying to recreate miles system, well sort of. On much smaller scale. What I'm trying to achieve is for receiver to react once it is hit with a beam from IR laser.

I chose IR laser because I have no experience with optics and I'm trying to keep cost to a minimum. If I get it to work I'll need many many sets of it. And the beam spread, at 100 meters a spread of even .5 meter is well accepted. Most likely I would use either optical sights or red dot sights set at 100 meter distance, for helping with aiming.

Also I'm hoping that I do not need to modulate Laser for this. Do I?

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Omnivent (author)GusevAnton2017-12-20

Hi,

If you want to be able to pick out the signal from ambient light, there's no escaping modulation, but if it's just a question whether the signal is there or not, this can be very simple. Just a 555 and a few "glue" components.

For max. signal through, the LASER should be driven at a current right before it "lases", where it's acting as a simple LED and then pulse it with enough extra current to bring it in and out of the "lasing" current range - it needds to be adjusted for the particular LASER diode.

On the receiving end, you can either use an integrated receiver like on TV's etc. which then determine the frequency of the 555, or it could be a completely new design with a tank circuit to "blind it" to DC and lower/higher frequencies.

I would advise using a small Fresnel lens on the receiving end as a minimum.

If you want to carry data or audio over this link, it's a more complicated story, needing faster receivers and a higher frequency of modulation.

Anyway, I don't iintend to scare you off it. It will likely be a fun experiment and the best way to learn is to dive in - then ask questions when they pop up.

I guess I don't have to tell you to start at a few meters and get it to work perfectly, before increasing the distance - small steps lead to the same place :)

If you like, I can post a simple LASER pointer driver circuit - just have to dig it up first - been many years since I made it.

Regards

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steveastrouk (author)GusevAnton2017-12-18

Yes ! It will be VASTLY easier to detect, if its modulated.

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