Open therm gateway, supplier


There is pretty nice open therm gateway project: A piece of hardware involved is a gateway itself. Not willing to purchase parts separately assemble and solder, is it possible to purchase ready-to-use assembled printed circuit board assembly?


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In order to get WiFi functionality, there is NodeMCU module offered in nodo-shop. I wonder whether the module requires flashing or it comes flashed already?

In case if it has to be flashed, where to get flashing guide?

Thank you in advance.


There is also this which I saw previously and saved for something to look up in future:

Wifi ready and a nice guide including how to set up a nice looking enclosure.
I emailed him and asked if it was possible to read from external sensors instead of connecting one to the unit and was told it is possible (he didn’t go into details?).

Forgot to say, if you do use this please post a guide!
I’d be very interested in trying it (I don’t like the idea of Nest etc servers going down now that I have a baby) but I don’t have time with a baby in the house to go through the trail and error of setting something like this up.
If I could just say to the wife “Give me an hour to follow this tutorial tonight” and end up with a working smart thermostat I’m much more likely to get the go-ahead.

I’ve been trying to set up a generic IP camera (I can’t find the right url to use) the for the last 6 months…

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Thank you for the input. The solutions seems to be interesting. I am not really sure whether I will use it since I am on Raspberry Pi 3B+. Indeed, I will post if any.


I am also on a Pi 3B+, that shouldn’t stop you from using it as it works independently to what you run HA on.

The same website has a guide on tweaking the sketch you program the D1 with so that it uses MQTT which means it will tie into any environment you use HA on as long as MQTT is set up.

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It needs flashing; see page 11 from

IT is in Dutch, but not to difficult to understand :wink:



Please post a link here how to reprogram D1 in order to enable MQTT. Seeking the website, has found nothing.


You use the kit I linked to first, but reprogram it differently. Obviously, where he sets up cloudMqtt we would use the built in add-on or mosquito instead.


Please correct me if I am wrong. All I need is open therm thermostat from that is merely composed of voltage/current level converter and Wemos D1. All required control functions such as OpenTherm implementation are stored in Wemos D1 flash.

The thermostat is able to publish MQTT status messages and is able to accept commands through MQTT messages.


If this is the case, I will definitely test it and post brief report here.


I’m not sure, I don’t own it myself (yet).

But from this video:

He shows a demo of it, and from the page where he shows the MQTT project he sets up a MQTT interface that displays current set point and temperature readings.
That makes me think the MQTT data will send current air temp at boiler, set temp, on/off status.
Which you would then set up automations etc in HASS to play with.
You could always email them to check? But from what I understand of the project it takes MQTT commands and converts them into OpenTherm signals to get your boiler to the required temp using the minimum amount of fuel needed (he explains the OpenTherm protocol on another page).

I plan on buying both shields off him so I definitely have everything I may need.

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Thank you for the input again. I will return back to the thread when I have tested the solution. I will get in touch with the author to check details.


No problem!
Hope it works out!

Did you go through with the purchase and setup? It sounds like a great project but can’t find much information on successful implementations.

so any news?


I have purchased all necessary components and ready to assemble and test a prototype. I have been short in time due to a number of reasons.

Hopefully, a prototype will have been assembled within two months. Winter is coming and that is the time to test thermostat.


Hi Hypnotia,

I’ve got mine otgw from the nodo shop, successfully assembled all of that and really happy to see it’s been working for a while. I’m not sure is that helps you particularly but I found that nodo shop version is quite easy to assemble if you get a manual on their website which is not simply found until you specifically seeking for one.

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ah yes, I got everything flashed and pretested, so I needed only to screw a few things and tightly put nodemcu on the board together with changing a position of one jumper.

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That might be helpful a bit :slight_smile:

I’m also wondering to build it .Currently i’m using De Dietrich MCR3 24T with DD home control OT module by .But i cant and dont have idea how to integrate it to HA.

This small module from Iho seems to be easy to use/build , i’m also wondering to use ESPHome on it, but i’m noob in programing so might be a challenge.


I have to replace my old boiler.
I’ve opted for an Opentherm boiler.

I’m using HomeAssistant. And I’ve read the documentation of the Integration “Opentherm gateway”.

My question: what is the best hardware that I can use? I’m still lost between some possibilities like : Nodo, ESPxx, Pyserial

I’ll install the gateway close to my new boiler. For the moment, I don’t have a proper cable that goes to that room. So Wifi seems me the only option at this moment to connect to the gateway.

Who can me propose some hardware?