[NJARC] A slightly off-topic request

[Dave Sica]

I am putting together a remote control circuit for use at our church to
switch the air conditioner thermostat on and off. I salvaged circuitry
from a defunct DVD player which will provide me with +5 and -5 volts DC
pulses as required. Now I need to make this control a relay that will
latch on with the +5 volt pulse, then latch off when hit with the -5 volt
pulse. 

Then it hit me: I could probably design a circuit to do that using vacuum
tubes, but that doesn't really seem like the right solution here ;-)

So I figured I'd toss this out to the *real* engineers out there. My
grasp of solid state is kinda weak, so although I could probably muddle
through this in time, I figure something like this must be the proverbial
piece of cake for a lot of our members. The circuit won't need to switch
any appreciable voltage or power, but I do want to use a physical relay
rather than a solid state switch of any sort.

I'll appreciate any suggestions!  I'd also like to scrounge up the
necessary parts if anyone's got the appropriate stuff lying around. 

Thanks,
--Dave Sica