> If it's a PIC, chances are it will work fine on lower voltages -
> like anything above 4V for some, and even lower for others.
> 9V batteries typically aren't a good choice if you don't
> need 9V

Yes, you'll get much better value by using 3 or 4 NiCd/dry
cells or a 6V sealed lead (if you've room) and a low dropout
regulator (if you need regulation) - ie not a 7805 - use an
LP2950/S81250 or similar. Presently 4/9ths of your 9V is
being wasted as heat in the regulator. The other step to take
is reducing current consumption - strobing displays or even
turning them off and make them visible on request, powering
sensors only when necessary and so on

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