PICers,
Thankz for all the useful i/p on this. To sum all the ideas up, the app would
require the cams to stand unattended for long periods, so battery life is a key
issue. Ideas like coupled coils & BFOs would need an osc running all the time
so battery drain would be an issue there. It looks like either a pressure
pad/vibe sensor or something like Honeywell's or NVE's mag sensors might be the
way to go. Haven't gone thru the data sheets yet but Honeywell's intro "Vehicle
Detection & Compass Applications", Caruso & Withanawasam, says AMR sensors can
detect a vehicle from the curbside. What you need is to put the whole thing to
sleep @ low quiescent current & rely on a passive sensor to wake it up on
interrupt. You might then even want some sort of secondary sensor to confirm
presence of a bandit: and that could allow a higher current drain if for a
short on-time. That sounds like a pretty standard design - but I'll need to log
date/time of events. Have some calendar chips in hand so will work on that part
& read up on the sensors. Thanks everyone.
Debbie

> What's wrong with a decent road hump and a weight triggered sensor near 
> it ?
> Peter

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