[Al Skierkiewicz]

Erin,
I looked at the Gadget Master II and it is designed to run small hobby motors at 12 volts output max. You can use a relay that is controlled by the Gadget Master to switch 12 volts to the compressor. Just wire the relay coil to the output of the controller and insert the normally open contacts of the relay in series with the 12 volt positive power supplying the compressor.
Are you coming to Atlanta, look me or Mark up and we can further explain. 12 volt relays with a coil resistance of 500 ohms or greater should be available at Radio Shack.