OpenTherm interface

by Alex Vieira

This is an OpenTherm interface.

It implements the OpenTherm physical layer, and the communication protocol, both from the boiler and to the boiler.

It takes the place of the thermostat, so somewhere, someone must decide on the setpoint temperature for the water in the central heating circuit, and send it to the JeeNode, who will then send it to the boiler.

The JeeNode sketch queries the air waves once a minute for a setpoint. It does this by sending out a package with basic status data, and waiting for a reply. If no reply arrives, it resends the same data one second later. It does this 3 times, and then it quits, putting the setpoint to 0.

It uses a homemade shield (a nice fabricated PCB is in the factory and should arrive soon), and a LCDPlug from the JeeShop.

Schematic, news and some snapshots can be found in:

I will add further documents as these will become available.

Code can be be found in (also download the OT libraries available as downloads on the same github place):

If you have any questions, just drop a line.