[sdiy] Has anyone seen (or played with smthing like) this ?

[Mike]

> >> But here they use the LEDs themselves as sensors in Phode diode
> >> mode ?
> >
> > Yep, and the thing is no use with any ambient light...
>
> Wouldn't it be easy to put together a negative version, where it
> sensed lack of ambient light from whichever diodes were covered?
>
How about feeding the illuminated LED's from a PRBS source, and correlating
to remove the ambient? I've made this approach work for acoustic radar.

Mike