Garage door opener

screenshot of garage door opener web site

From my phone or other web browser, I login to my secret control panel site via openid. That site shows a garage door opener page:

screenshot of garage door opener web site

Sliding up the virtual cover fetches a one-time use code (something like Post Once Exactly). The code even expires after a few seconds, in a further attempt to prevent accidents.

screenshot of garage door opener web site

Submitting that form sends the code to my web server, which can send an internal HTTP PUT to a service on the garage computer. It's like my parport-serve HTTP-to-parallel-port service, but different since it also drives a shiftbrite on some of the pins.

The parallel port service holds a pin high for a few seconds. This signal goes through a big low-pass filter to avoid accidental opens due to noise, a transistor for amplification, and then to a relay connected to the garage door opener's input (where the standard buttons are connected). The filter takes more than a second to activate the relay. Relays make a different sort of clicking sound when you fade them on like that.

garage door control electronics
garage door control electronics
garage door control electronics
garage door control electronics

Brad Fitzpatrick uses an X10 relay unit in his similar setup.