You could write a daemon on the empeg that polls your home computer via ssh. Assuming your home computer isn't reachable across the Internet in general, then the only way your empeg could ever successfully make a connection is if it was within radio range. You wouldn't have to worry too much about associating with a different base station and accidentally opening your garage door while you're nowhere near home.

(If your home computer is reachable from the net, then you'd want to run ssh over a non-standard port that your firewall filters. If you had an adversary who was willing to stand next to your car, in the parking lot, and maintain a separate connection to a conspirator standing next to your garage, they could possibly convince your car that it was next to your home and get it to open your garage door remotely. Whether you think anybody might want to mount such an attack against you is another matter, of course.)

There are other risks, though. Imagine when a war-driver (or a sneaky friend of yours) associates with your in-car base station. Assuming they use the appropriate tools to get around your WEP key, now they can run emplode against your car stereo. If somebody wanted to give you a hard time, they could replace all your music with Wesley Willis.



Now, how do you propose to close your garage door? If you closed it with your normal beeper, your empeg might associate with home and helpfully open the door again for you!