Giles.H wrote:
>OK, their are a 100 ways to do this, but I don't want to re-invent the
>wheel.
>  Are their any reference designs for something like the croaking frog that
>makes noise when someone walks in front of it?  Are they using a
>photo-resistor and sensing change with a low pass filter?  Are they using a
>photo diode? Photo Transistor?  If so, how do they avoid total
>saturation?
>


No reference designs, but for detecting hoomanikans, you might
check out the passive IR - PIR detectors.

Hostfelt Electronics has some for about $5 - I have 3 coming in
this week, and will see if they actually work. I plan to build a
narrow field sensor - one sensor in a tube/whatever sensing ahead
with 2 surround detectors possessing wide peripheral vision that
provide inhibitory surround input to the central detector
- attempt to try to localize the receptive field.

best regards,
- dan michaels
www.oricomtech.com
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