Bodgetts

There are a lot of ambient noise sources these days. TV remotes use a modulation frequency of around 53 KHz to modulate their controllers light source. An "on" signal is actually modulated light. Very long code sequences of the mfg's choosing are used for differentiating button functions. The code sequence is unnecessary for your application. You may want to modulate the laser on/off at some carrier frequency. Use some form of limiting after the detector. Feed the output of the limiter A/C coupled into one of the PIC timers to correlate correct modulation frequency. If you come up with the correct count after integrating over a period of time then you can say you have hit the target.

- Martin