> It would be relatively trivial to design a circuit that uses current
> sensing to detect pump failure. Current to the pump that falls either
> above or below the design window can be used to trigger an alarm or
> activate the backup. Response would be nearly instant.

Relatively trivial to you, perhaps. Current sensing sounds like a great way
to spot a fuel or water pump failure, or even potential for failure. I
managed to build an RST intercom that sorta works. Could I build one of
these gizmos? What would be involved?
John Slade (electronically challenged, but keen to learn)