In article , Hughes <hi100@xxxxxxxxxxxxx> writes
I don't know anything about the Polaroid units but you might open one
up and check who made the
transmitter ic. Usually these single chip designs are of the "garage
door opener" variety. Often
the older units operate in the unlicensed band ~315MHz. A very popular
old chipset was made by
National semi-conductor, so the application notes on their website will
help you figure out range
etc. More recent vendors are Micrel,Maxim Semi. etc Newer units often
run in the unlicensed
900MHz ism band. You can buy modern postage stamp size complete hybrid
transmit and recieve
devices from companies like LYNX Technologies, very inexpensively which
only need a 6 in wire
antenae and 3V battery to get 100ft+ range. You would have to add a Fet
transistor to the output
to operate the winder. Digikey sells the devices by mail order and the
Lynx website has good
application notes.
That is the route I took, using a Motorola module and key fob for a car
alarm control. The receiver output is a power rail pulse which I wired
to drive a FET shorts the terminals of the motor drive jack lead when
switched on. The whole receiver unit fits into a small box slightly
larger than the PP-3 battery it uses for power, complete with a solid
antenna which operates the on-off micro-switch when it is extended, and
a red LED on indicator. The unit plugs into the 2.5mm socket on the
motor drive. The range depends on the key-fob used, but the one I
selected works at well over 100yds, though I have never used it "in
anger" at that range, just tested it.
--
Kennedy
Yes, Socrates himself is particularly missed;
A lovely little thinker, but a bugger when he's pissed.
Python Philosophers
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