MySensors thermostat

[dbemowsk]

Has anyone successfully interfaced a thermostat with Domoticz using MySensors? If so is there some sample code out there that I can look at?

[alowhum]

Did you succeed in building this?

[gohan]

@alowhum
What are you trying to do?

[dbemowsk]

@alowhum First, I am no longer using Domoticz, but when I was using it, I did have some control of my thermostat. The code was pretty hackish, but it worked. I don't know if I have that handy.

My interface was an RS485 converter that talked to my RCS serial thermostat. With Domoticz, I was able to read the thermostat temp, set the heating and cooling set points and change the mode (heating, dooling and off/auto).

I have since acquired a VeraPlus controller, so I don't know if I have the code handy any more.

[alowhum]

This is what I'm trying to do:

[gohan]

You basically want to bypass your thermostat, I'm am also looking for a similar project using a sonoff dual. The main problem is implementing an hysteresis logic tuned for your heating system. There is a post in the Domoticz forum, I remember reading it but it's not really a walk in the park. At my house I bought a netatmo thermostat that was on sale for 105€ and I must say it was a really good purchase, I'm very happy with how it performs and it was a direct swap of the old mechanical thermostat

[alowhum]

My house doesn't have central heating, so for me this is a useful route. Loads of people are buying Infrared Panels as well, for example to only heat their bedroom at night, or their bathroom in the morning. This could be useful for those situations.

[gohan]

Well, it depends the level of home automation you want to reach

[dbemowsk]

So, I am assuming that you maybe have an old mercury dial thermostat or something similar, correct? If that is the case, all you have to do is implement a bypass relay that when off connects the old mercury switch thermostat, but when on allows control from a second relay controlled by the Pi thermostat. The bypass relay would remain on while the Pi is powered on and able to control the system, but in the event of a failure of the Pi, the bypass relay would fail over to the old thermostat.

[alowhum]

No, I have a gas-heater that has a powerplug to turn it on and off. As binary as it gets.

What I was looking for MySensors code for a node that is a stand-alone thermostat, but that can also be given an override setpoint through Domoticz.
I am looking for tips/code that will let Domoticz send a keep-alive signal to the node.

Basically I'm looking for ways to do this robustly and securely. There are so many configurations possible.