We’re just about there with the REV7 circuit board. This is the version with an H bridge to control a motor. Here’s the recipe:
1) Take one REV7 circuit board
2) Add in a sprinkling of firmware
3) Combine with a commercially available, low cost valve
4) Replace the commercial valve’s controller board with a REV7 circuit board (note that it is not the correct form factor, there will have to be some inventiveness with enclosures and physical controls)
5) Deal with the shaft encoder (3D printed bracket?) and the motor connections
6) Hey presto! A fully working OpenTRV controller at minimum cost for this winter heating season
Once we have a run of REV7 boards in January, we’re looking for volunteers to help work out the neatest/best way to put the electronics together with the motor from the commercial valve. We’ll send you a REV7 and one of the valves and set up a wiki or similar so that everyone can work collaboratively on getting the REV7 talking to the commercial valve hardware.
Drop us a line at firstname.lastname@example.org if you are interested and have some time towards the end of January.