Searching for and responding to a modulated signal from LED

Other Hardware 3rd Party Boards
1

Hi everyone,

I'm working on an underwater camera trap idea. Having tried 950nm LEDs as I would on land and found them to only penetrate 30-40cm in water, I'm going to try blue or green LEDs or even a low power laser. I need only 1.5m max. The questions I have are:

  • Does anyone know code to read a 38Khz signal and respond when it's cut? (I'm hunting around online right now) and,

  • What sort of phototransistor is good for blue or green light? I'll put a blue or green filter over it anyway.

Cheers

Nathan

2

What generates the 38kHz signal? Can you get a 38kHz signal from a green or Blue LED?

Paul

3

Water as a medium results in a lot of scattering.

4

I think there are simple laser "break beam" motion detector kits available.