how to Re-Use old remote control?

You're probably out of luck since most (all?) modern automobile remotes are encoded, where the transmitter and receiver have to be "matched." See

One option is this gizmo from over at All Electronics Corp.

They have a couple of others if you go up a level (or search their site for "remote"). I'm sure that there are other sources out there but I've been an All Electronics customer for years and been pretty happy with their stuff.

Read the user comments on the linked remote unit for some application and operating hints.

Well, if you know someone who has a spectrum analyzer, you could borrow it to find out what freq. your fob is transmitting at, and build a little receiver for that freq. Then, as long as it's not spread-spectrum or something, your receiver will just give you whatever pulse train the transmitter is sending out. Since you only want on/off, you can filter those pulses out.

If you want to go the RC route, I have a couple of little toy RC cars - the cars are about 1 1/2" long, with two channels - Forward/reverse and right/left turn.

But the xmitter is on a single-sided board about the size of the palm of your hand, in a box that you hold in both hands. (like a 6" French roll.) They operate in the 27 MHz CB/RC band.

They were about two bucks apiece at the drugstore clearance table one day; I'll send you one for, say, ten bucks for the box and my time to pack it.

Good Luck! Rich

If you don't want to screw around, you can try the transmitter/receiver linked below:

$6.60 + $5.00 shipping. 4 channels. Easy to apply.

This combination works very well in my digicam intervalometer/remote project:

Have fun!

Tom