Hi folks,
I am kinda new to the community, not so much to home automation. So let me tell you about our situation. We are located in rural Germany and our main source of heating is a czech wood jetstream furnace (“Holzvergaser” in German). This is a very efficient way to burn wood and it produces a good amount of heat. That heat needs to be stored in isolated water tanks. I have two of these tanks with 2,000 liters each. And every couple of days (3-4 days in winter) I have to fire up my furnace to “load” the tanks again.
Each tank has three PT1000 temperature sensors that measure the temperature on top, middle and bottom. As soon as the top temperature reaches below 50°C I have to light the furnace. Until now my daily routine was in the morning to go out into my shed where the tanks are located and check the temperature. This was a very tedious job and really needed an alternative way.
As I already have the heating control visualized in Home Assistant my idea was to create a device that reads those PT1000 values, digitizes these and provides a REST-API for HA to get that data. So I sat down and looked for a good quality and affordable solution. There are sensor loggers out there. But you can spend a fortune for those and then they never provide a nice REST-API. So I looked at AliExpress and found a 8-channel-Modbus-module that does the trick. I then read the modbus messages with an ESP32 and created the webserver that provides the API. On the other side I created a simple custom integration component for HA that reads that API and provides the values of each sensor as entities.
The whole project is of course open source and you can find it on GitHub:
There is the sourcecode for the custom integration, the ESP32 and also a list of parts to buy from AliExpress to rebuild it yourself.
I would really like to get your ideas about that project and maybe someone rebuilds it, then drop me a message!
Cheers
Johannes
