The Fibaro FGK101 is talked about a lot. In the thread I linked to, , but that device has since been discontinued. I started another thread to see if anyone knows of a similar battery operated replacement.
There are multiple micros which are mains powered that can connect to a probe. This includes the FIBARO RGBW controller, the Fibaro Universal Sensor, and one of the Aeotec micros, But I don’t remember which one.