> > I am planning on using it as a proximity sensor similar to the 
> > microwave field sensors found in car alarms used in convertibles.
> > Is this called a doppler effect sensor?
> 
> Yes. It senses motion and reflectivity. It won't tell you how 
> far away anything is.  I've used these sensors many times.
> 
> A cockroach at 6" looks the same as a man at 20'
> An RF absorbing surface can move all it likes and not be detected.
> It also can't discriminate between it's own motion, and the 
> motion of anything else. 

That's okay.. I am planning on using it to trigger a animatronic 
when something comes walks into its field. I understand they actually
cant do 360 deg since it radiates out in a directional pattern based 
on the antenna orientation. 

>Schematics won't help much with microwaves. The PCB and enclosure ARE 
>part of the circuit. For some of these devices, the antenna is also 
>etched right into the board. Trace widths and lengths, and type of
>material are critical.

Hmm, since I am not an EE I'll stick with a premade 
sensor I guess. Any ideas where I can get them the cheapest? 

Thanks, 
Mike


-- 
http://www.piclist.com PIC/SX FAQ & list archive
View/change your membership options at
http://mailman.mit.edu/mailman/listinfo/piclist