Fellow Listers:

I have an interesting little project.  I would like to (read: hope to) find
a cicuit that will detect that an item (in this case, small fridge) demands
power.  Typically, it sits there in open circuit not requiring any power.
When the thermostat calls for cooling, or the door is opened, some circuit
is closed and power is required.

Is there some simple and relatively inexpensive method where a circuit can
be inserted between the fridge line cord and the wall socket?  The circuit
would have a low voltage output signal (say maybe an opto-isolator/coupler)
that can be used as the output indicator.

To be more specific, I want to run this little fridge on an AC-DC inverter
that does not have a hunting function.  So, using 12V from the DC side, I
need to detect that the fridge requires power, use the signal to replace the
small power switch on the inverter, turn the inverter on while the fridge
requires power.  Then turn off when the fridge does not require power.  The
tricky part (for me) is that since there is no 120VAC available at the time,
in this scenario, we cannot try to detect current flow into the fridge.

Thoughts, hints, URLs ????


John

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