“This project started a long time ago, the idea is to be able to control the two garage doors remotly.
Before anything else, you have to understand how the door is working, each door has one button, press it, it opens, press it again (in the middle) the door stops, press it again the door closes.
One problem common to all version is that the original button and the rf remote need to be kept functional “just in case”
The 1st version that I made was a simple Arduino with an ENC28J60 and a relay board. You could open the door by sending a UDP packet to the Arduino, and it would power the corresponding relay bridging the door button, after a while I added an authentication message that needed to be sent before sending a command.
The 1st version had a major flaw, it’s freaking hard to send a UDP packet from an iPhone with a nice interface without a developer license and all. So the second version used a web interface works great except that it broke every 24h so I kind of dropped it.
The 3rd version has been designed and built to be much more stable/secure.
So, I had multiple options, using a state machine that updates by listening at the button isn’t a very good solution because a desynchronization could happen and f-up the whole controller. Instead, I wanted feedback on where the door is (or will be) so it was time to reverse engineer the original controller board.
After a bit of thinking using the STOP-CLS and STOP-OPN switches NC signals (which were unpopulated) are perfect to find out if the door is open or closed. However, if the door is stopped in the middle and if we send an order to either open or close the door I also need to know on which direction to door is going in order to stop it and repress the button to let the door go in the other direction.
In order to do that, my best option was to use two DC optocouplers on the motor terminals in order to determinate the direction of rotation of the motor.
At first, I wanted to avoid soldering myself to the board and only use the available terminal blocks. However, an issue with that is that there was no DC positive to power the optocouplers that was available.”