I am making an IR beam break sensor for short range (circa 3cm). I would like to use the filtering built into the remote control sensors but I know they need a coded signal.
I belive there is one which can accept a continuous (40 kHz ish) stream which would make things simple but I can't find such a thing.
Does anyone know a part number?

 

The last time I had to use one it was Panasonic PNA4602M.
I have not looked to see what is available on the current market.

 

Have a look here:

https://uk.farnell.com/c/optoelectronics-displays/uv-ir-components/ir-receivers

 

Does it have to be coded over such a short distance? I'm thinking about one of those IR avoidance sensor modules popular with robotics.

 

3 cm- you would have trouble making the signal weak enough to NOT overload the AGC in the receiver, and all that extra monkey business of modulating the beam.

Just use a plain old IR LED and Phototransistor combo.

 

3 cm- you would have trouble making the signal weak enough to NOT overload the AGC in the receiver, and all that extra monkey business of modulating the beam.

Just use a plain old IR LED and Phototransistor combo.

It would just need a suitable resistor in series with the LED.
A plain LED/Phototransistor would be fine except that I would need to go around adjusting the sensitivity every the sun came out or went behind a cloud. Reliability is very important.

 

If I need a '555 to generate the 38kHz then I might as well use an 8 pin PIC and generate a full IR code and another similar PIC to decode it at the other end. I don't think I could improve on that for reliability.