Peter L. Peres wrote:
>
> > I would like to find something that could wake a PIC from sleep with
> > ultra low current for sensing.
>
> Well, if you want real low power, then you have to rely on something that
> your quary produces plenty of. That would be mass (step-on mat), noise,
> air movement, and electrical field disturbance (large conductive blob vs
> non conductive air). IR radiation for a PIR will be low but it is well
> known that it works.

Good old fashioned normally-open contacts
sound ideal for zero-power sensing. Many
pressure mats are this type, also reed
relay/magnet or microswitches.

As a more high tech alternative, maybe a
piezo sensor which uses zero-power but can
still generate a pulse from some mechanical
movement. :o)
-Roman

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