This has been in my “to-blog-about” queue for a while, and seeing this post on the Make blog tipped it into the “must-blog-now” category. Summary: combine a wifi adapter, some sensors, and some electronics and you can monitor your garage online.
A few months ago, I had a similar idea but took a different approach. I was a bit more speed-oriented (some might say lazy) and decided to use the X10 system I already have going in the house. Maybe not as elegant or robust as making a circuit from scratch and hooking it directly into the ethernet, but
I used an X10 Powerflash module connected to a reed switch mounted on the overhead door. When the door changes state, it sends an X10 code of on or off, telling if the door was just opened or closed. The signal is received by an X10 CM11A attached to the house server, which triggers a short script that logs the time and status in a text file (again, “speed-oriented” .. as in speed of completion). Another script generates a (SSL and password protected) web page displaying the current state of the overhead door and time of last change: “Garage was opened at 8:00 am”.
Now I have webpage that tells me I left the garage door wide open when I took off for work … if only I could close it remotely! Once more, with ease-of-installation in mind, I grabbed another X10 product from Fry’s, the Universal module and wired it to the same contacts that connect to the wall-mounted door-opener button. A small addition to that web script, and a click will use the heyu program to generate the proper X10 signal, causing the relay to fire and close the door.
Our garage door has an “electric eye” to detect an object (or person) in the path of the closing door, and will reverse and refuse to close if something’s in the way. (I believe this is required by state law.) It’s still possible to close the door on your car if the bumper and the beam are at different levels, but at least it makes it harder 😉 There’s an LED on the sensor itself, but it’s hard to see from inside the car without adjusting the side-mirror to an odd angle. So there’s a possible enhancement to my version of the garage monitor: use the signal from the original obstruction sensor to drive a second better placed LED.