I am looking for a thermostat that can read the temperature from a boiler (using something like the DS18b20) and then ouput a signal so I can turn on or off the boiler depending on my settings.
Anything ready out there?
What country are you in? The device selection does vary.
Also, do you have a smartthings/Aeotec hub, and if so, which model?
Meanwhile, take a look at the following FAQ, it should have some candidates for you. The DS18b20 is an external source in this context.
Devices that work with DS18B20 Probe sensors that have working Edge Drivers (2023)
I am in Portugal.
Smartthings v2.
Thanks
Sorry, I posted the wrong link, just a second.
Ok, I have fixed the link above to the FAQ that is specific to probe sensors. Since you are in Europe, you actually have more candidates than those in the US.
Still another option might be one from Qubino, but I haven’t yet seen an edge driver for that model. 
When I was upgrading my setup, I wanted something similar—smart and efficient. I ended up finding a thermostat that could sync with my boiler using a DS18b20 sensor. It was a game-changer!
If you’re on the hunt, I’d suggest looking into specialized boiler repair Surrey services. They often have insider knowledge on the best gadgets and solutions.