ESPHome support

[rdehuyss]

Hi, are you considering support for an ESPHome module?

This would increase your potential market by a lot...

Thanks!

[Jeroen88]

Hi Ronald, I would surely consider supporting ESPHome, I already took a quick first glance and it looks indeed very interesting. Do I understand correctly that you need Home Assistant? And that MQTT is the protocol used to communicate between HA and the devices?
I already published a first draft example of a MQTT thermostat in the examples? What would you suggest that is needed to support ESPHome?

I think it would be nice also if the MQTT thermostat could listen to a (external) temperature device!

[bwired-nl]

EasyOpentherm supports mqtt, which can be used by all Home automation software for example also Home Assistant and Domoticz

[Jeroen88]

So the MQTT example in this library supports your needs?

I am working on a next version of the MQTT example, a different loop() and adaptations to the logic how to decide to turn the boiler on and off. As soon as this is ready I will make a new release. So keep an eye on the changes. Also I am considering ESPHome native API support after updating the MQTT example.

[Jeroen88]

I am still working on this. The new (yet to be published) thermostat implements a state machine: from WAITING_FOR_BOILER (no valid response received yet from the boiler) to OFF (boiler connected but thermostat in off state and does not react to changes in room temperature) to IDLE (thermostat reacts to changes in room temperature but the current temperature is within range of the room temperature set point) to either HEATING or COOLING (boiler is running) to ANTI_HUNTING (after a running cycle, boiler will not start running again for 5 minutes) to IDLE again. In any of the previous states but the first it can go to OFF if it receives a command to do so. From OFF it goes to any of the running states only by changing the set point. The state is selected depending on the difference between room temperature and room temperature set point. This new thermostat also implements a dead zone (i.e. temperature needs to drop below set point minus dead zone before heating starts up).

In this new thermostat the WiFiClientSecure is changed into a WiFiClient, the certificate is removed and the HiveMQ external broker is replaced by the Mosquitto broker, because running Mosquitto over a "normal" (non TLS) connection is a more logical scenario from a home assistant point of view. In this way it will seamlessly work with the MQTT integration present in home assistant.

I am also investigating MQTT auto discovery, ideally I want the MQTT thermostat be discovered automatically by the MQTT integration as a HVAC integration that can be controlled by a thermostat card if this is possible.

I will publish this new MQTT thermostat within weeks.

Also I have developed new hardware: an OpenTherm shield especially designed for an esp32 S2 mini that I expect to work also with an ESP32 C3 mini or even the older ESP8266 D1 mini. This will be available within 2 weeks I think.

[ananyevgv]

https://github.com/rsciriano/ESPHome-OpenTherm
https://github.com/wichers/esphome-opentherm
https://github.com/KPWhiver/opentherm-gateway-esphome
https://github.com/rysiulg/opentherm-ha
https://github.com/stoyandim/daikin_residential_brp069a62_opentherm

[Jeroen88]

@ananyevgv thank you for all the links! :). Currently I am working on the MQTT integration of the EasyOpenTherm library for Home Assistant. The links you provided help me to create a native API version afterwards.
The difference between the solutions of the links that you provided with the solution I am developing are: I am focussing on offering a high level API, basically setting the room temperature setpoint and providing or measuring the current room temperature only, and the controlling of the boiler being taken care of by the library. My solution is not a gateway but a replacement for the wall thermostat, communicating with HA not by serial but using MQTT messages (and the HA native API later on). I did not investigate the fourth link due to lack of structure of that repository. I just quickly read about the Daikin solution, which seems to me an integration of an existing hardware component with HA, so a very different approach than EasyOpenTherm.

My short term goals are:

• Offering a high level API to a fully automated thermostat controlling the boiler
• Auto discovery of a Climate entity in Home Assistant
• Auto discovery of several sensors and binary_sensors (currently boiler setpoint, boiler flow temperature, boiler return temperature, WiFi signal, flame ON/OF, hot water for CH/DHW. These sensors are easily extendable
• Offering generic hardware for any microcontroller and dedicated hardware for an ESP32-S2 mini, ESP32-C3 mini that most likely will also work with the ESP D1 mini.

Ultimately this will lead to: setting up the MQTT integration in Home Assistant if not already done, set your WiFi and MQTT credentials, compile and flash the microcontroller, connect it to the two OpenTherm thermostat wires to the boiler and you are ready to go. Should be ready before the end of this year :).

[ananyevgv]

Hi friend. It would be very nice. I tried many implementations, but unfortunately I didn't get what I wanted. I'm ready to test your version. I can throw off a few more links., with the implementation of mqtt.

[ananyevgv]

https://github.com/DRazumovskiy/Baxi-Luna3-Comfort-IN-HT-Solar-MQTT/tree/master

[Jeroen88]

Hi friend. It would be very nice. I tried many implementations, but unfortunately I didn't get what I wanted. I'm ready to test your version. I can throw off a few more links., with the implementation of mqtt.

Keep an eye on this repository, when the Home Assistant MQTT auto discovery example is ready I will issue a new release.

[Jeroen88]

A small update for if you are interested :)

• New hardware shield is functioning correctly, I will put it in my Tindie store at the same time I update the library on Github
• MQTT auto discovery took a lot more time, because the documentation is not very clear. Also fully functional now, although I think I have to spend some time on retention of the right messages
• A Climate entity is auto-"magically" added with "off" and "heat" button if the boiler is heat-only, and extra "auto" and "cool" buttons if the boiler can cool
• The thermostat not only can use a local temperature sensor but also listen to an external thermometer already present in Home Assistant. For this I wrote an automation Yaml that picks up the thermometer value and forwards it to the right MQTT topic in the right JSON format
• A Domestic Hot Water (DHW) switch is added, if the boiler supports DHW. When switched off the boiler will not produce domestic hot water
• The following sensors are always present: flame (on/off depending on if the boiler is burning), RSSI (WiFi signal strength), boiler setpoint (target temperature for the boiler),
• The following sensors are only added if the boiler supports these: water pressure, flow temperature, return temperature, relative modulation, domestic hot water (if 'on' and flame is also 'on' the boiler is running for DHW, if 'off' and flame is 'on' boiler is running for central heating)

Still a lot of code cleaning to do, updating the state machine, adding comments in the code and adding a description for MQTT example. So give me another few weeks.

[Jeroen88]

@rdehuyss, @bwired-nl, @ananyevgv I just pushed a new release v1.1.0. Apart from a few minor changes, the Advanced_Thermostat.ino example now is a Home Assistant fully functional auto discovered MQTT Climate HVAC Thermostat:

• Set your WiFi and MQTT credentials in Advanced_Thermostat.ino
• Check the OT_RX_PIN and OT_TX_PIN GPIO's used to communicate with the OpenTherm controller if you do not use the shield (The GPIO pins have been changed since the previous release to match the shield)
• Flash to an ESP32-S2 mini or an ESP32-C3 mini. These boards have been tested. It will definitely work on other ESP32's too, for an ESP8266 some code changes are needed but could work too.
• VERY IMPORTANT: add an automation in Home Assistant that forwards the room temperature from an existing thermometer in Home Assistant to the right topic (see README.md for instructions on how to do this.
• Connect the two OpenTherm thermostat wires to board or shield.
• Power the ESP32. The MQTT HVAC Climate control should be auto discovered on the Home Assistant dashboard. If no temperature is shown just above the middle of the thermostat, the publishing of the room temperature is not correct yet. If the EasyOpenTherm board or shield is not communicating with an OpenTherm boiler (e.g. because the wires are not connected yet) the HVAC Climate entity will appear in Home Assistant but disabled.
  If you already see the entity appear you are on the right way!

The MQTT Integration and a MQTT broker (like Mosquitto) should already be installed without TLS / Certificate and reachable on port 1883.

Please report back your experiences!

[ananyevgv]

Compiled it, I'll try it in the evening. Will DS18B20 work too? It would be nice to add an MQ5 (or similar) and a relay to control the gas valve.

[Jeroen88]

@ananyevgv if you set the const int oneWireBus here to the GPIO where your DS18B20 is connected, the program will publish the room temperature measured by the Dallas sensor to Metriot/EasyOpenTherm/112233445566/climate/state in the format {"local_temperature":19.8} (you have to replace 112233445566 with your unique chip ID). If you want to use that temperature you have to send it back by publishing it to the same topic in the format {"temperature":19.8} using a Home Assistant automation.

So the decision which thermometer you use to inform the thermostat of the room temperature is made in Home Assistant (or any other home automation system: the thermostat subscribes to .../climate/state topic and uses the temperature it gets with the right JSON key "temperature").

[Jeroen88]

@ananyevgv the MQ5 is a gas sensor, not a thermometer, so not usable for the purpose of measuring a room temperature. I used a I2C BE280 in the MQTT_Advanced_Thermostat.ino example, please take a look there if you need an example of how to read another temperature sensor. Next adapt the program to integrate those readings instead of the Dallas.

But the best option is to use a thermometer completely independent of the thermostat and publish the value to the above topic in the right JSON format.

For other home automation systems based on MQTT I would also suggest to use the new Advanced_Thermostat.ino example, because this is also based on MQTT and far more complete than the older MQTT_Advanced_Thermostat.ino example. With the new example just do not subscribe to the Home Assistant auto discovery messages.

[leovanalphen]

Question, can this work together with zigbee smart radiator valves/buttons? I currently have a Nest thermostat, Nefit opentherm CV and dumb radiator valves. But I don't like the nest and I would like to be able to heat and control heating for separate rooms. (I work from home, so most of the time i'm sitting in my small office, no need to heat the livingroom for example) + I'm really interested in getting more insight what my boiler is doing. I've also looked at Tado and Evohome but these are cloud based, I would really prefer something local for multiple reasons.

Can I use either your OpenTherm shield or OpenTherm controller to heat rooms independently with zigbee radiator valves via Home Assistant? I already have temperature sensors in every room + what I can see most of the smart valves also have a temp sensor.

Would something like this work? Thanks in advance!