There are several implementations out there using an RPi to check the status of the garage door, including the following which has a web server:
This could likely run on the same RPi running OSPi. Of course, it would be more fun and educational to “roll your own.”
That’s funny because I was looking at the exact same hardware yesterday. However, he uses a 2-relay board and I’ll probably get the 4-relay board from the same manufacturer – just in case I need an extra relay at some point. Plus it’s only a couple bucks more than the 2 relay version.
It’s also worth noting that the magnetic sensor that he uses is relatively weak – it requires the contacts to be within .25″ of each other to be closed. On a garage door I’d prefer something with a little more wiggle room (like .5″ – 1″).
I really enjoyed the info about his authentication system.