Look for some automobile alarm systems. I bought a 7 channel remote control system (main control brain with 2 remotes) a while back for a customer's car to control locking the doors, unlocking the doors, rolling the windows up and down, opening the trunk, and arming and disarming another brand alarm system.
I just looked at the control brain and remotes out in the garage but there was no brand or model info on it and I can't remember who I got it from but a google search should show up something. The 7 channel one I have on the remote there are only 4 buttons and by pushing buttons 1, 2, 3, or 4 you can activate outputs on the control brain and then by pushing buttons 1 and 2 together you get another channel output, push buttons 1 and 3 together for yet another channel and so on.
If you find a remote control alarm type system with enough outputs you could use one button to open your one garage door and another button to open your other door. Since the alarm is 12 volt based you could probably get by with a basic 110 volt AC to 12 volt DC adaptor by figuring out the amperage needs.
The old garage door open/close buttons mounted inside the garage on the wall were nothing more than a normally open set of contacts. Push the switch and the contact closed connecting the two wires run to it together. By using a 12 volt relay with the alarm, you can mimic the operation of the inside push button switch.
The nice thing with the small remotes for an alarm is you can keep them with the keys. If the car get's broken into they cannot take the remote off the visor and drive to your house to break into it and with them being with the key's if you get inside the house with a detached garage and forget to close the door you don't have to run back outside to close it.
Jim
