Hello
I want to make a counter using a laser emitter and receiver.For the receiver i have used photoresistance but it was not a good solution because this receiver is very sensitive to the ambient light.Can you propose to me a suitable laser detector that can ot be affected by the interference with the ambient light emitted by the lamp.
Thanks
I made one to count the swings of a pendulum using just an ir led and ir photodiode. Worked fine, but they were only a cm or so apart.
Alternatively you could do what this guy recommends, and use something which detects IR modulated at (say) 38kHz. He uses a Panasonic PNA4602M; I've used a TSOP34838. Of course you need to modulate the source at 38kHz. You can do that easily with the Arduino tone() command, or use say a 555 like in that link.
Azzali:
Hello
I want to make a counter using a laser emitter and receiver.For the receiver i have used photoresistance but it was not a good solution because this receiver is very sensitive to the ambient light.Can you propose to me a suitable laser detector that can ot be affected by the interference with the ambient light emitted by the lamp.
Thanks
Can't be done. The work-around is to modulate the laser signal and then have the receiver detect the modulation.
Look at how your IR remote control works. Same principal.
Paul
Azzali:
Can you propose to me a suitable laser detector that can ot be affected by the interference with the ambient light emitted by the lamp.
Why do people always think 'laser' for a beam break sensor.
Just use a narrow beam IR LED as 'transmitter', and modulate it with 38kHz.
And a 3-pin receiver made for beam break, like the TSSP4038 (not TSOPxxxx).
The 3-pin receiver is designed to ignore ambient light.
Leo..
Wawa:
receiver made for beam break, like the TSSP4038 (not TSOPxxxx).
I had forgotten about the TSSP. Remind me of the difference please @Wawa? I recall something about the tsop resetting after a certain time of modulated but continuous input, which makes it suited to tv remotes, while the tssp is happy with a continuous stream and thus ok for proximity sensing?
Correct, most 3-pin receivers are designed to only receive/detect bursts.
Leo..