WeMo Garage Door Opener

After adding the small capacitors on the long transmission wires with the reed switches, the stability of the Arduino was much better. Instead of freezing/hanging once a day, the frequency was now once every few weeks. But it still happened. So I put some more capacitors on the long wires but this time closer to the Arduino I/O pins instead of the ones I initially put on the reed switches. This caused other issues and made the Arduino not able to sense door status properly. Then I had the realization that it was not RFI interference anymore and that the likely culprit was the pull_up resistors I was using on-chip on the Arduino must be very big and not pulling up very "hard". So I changed the Arduino code to eliminate using those on PIN 4 and 6 (the reed switch I/O ports) and instead soldered in some roughly 350 ohm resistors between the I/O port and +5V (pull ups). I think this will pull up much harder and likely keep the 5V (ON) logic in place solidly when the reed switches are open (N/C). Time will tell, but I am thinking this is the last improvement :-)

Ughhh, sorry. Here it is: https://github.com/cdhutzler/wemogarage

Note: When you first turn on the Arduino/Wemo system, it takes the Wemo time to crank up, attach to WIFI, etc. The Arduino starts up much faster, of course. But because of this, on startup (or a couple of minutes after), the system may be out of sync in that the WeMo and the state of the garage door are not properly matched. Simpy opening or closing the garage door once will sync things up. I can't think of a good way to fix this issue as I would love to sync everything when the Arduino starts up but I can't since the WeMo takes so long to start up. I could just put a silly delay in the Arduino start up code and maybe this is the best solution. then after the delay run the normal "sync" operation in the Arduino code (which is already there) and things will be happy.

Added in some 100µF ceramic caps across each of the input/output lines that fun from the Arduino board out to garage components. This includes the lines that go out to the reed switches which detect the garage is open or closed as well as the lines that go to the garage door motor telling it to switch state. What I think was going on was that sometimes the spark of the garage door motor starting caused enough RFI coupling into those fairly long wires that it would cause a voltage spike and essentially render the Arduino into a hung state. Seems to be much more stable now for months at a time (instead of a week or so). YMMV on this one :-)

Initially used a relay to trigger the garage door which just wants to be shorted to ground for a half second or so. But for the final version went to a (solid state) Darlington NPN transistor which is much simpler, cheaper, smaller, and just the right way to do it.

So sometime in the Spring of 2014, Belkin will begin selling a "Maker" version of the WeMo switch. Not exactly sure if it will cost less or be better than taking apart a normal WeMo device. But looks positive. If it has all the right pin outs, it could be a lot easier to use one of these compared to soldering in a wire, etc. http://www.belkin.com/resources/img/press/hi-res/Belkin-WeMo-maker.jpg