@Nca78 Thanks for the advice.

Hi,

I love this project. This is almost exactly what I wanted to do by myself (but I have no knowledge in PCB design). As this project shouldn't require much power, have you ever though about using a dropping capacitor PSU (http://www.circuitsgallery.com/2012/07/transformer-less-ac-to-dc-capacitor-power-supply-circuit2.html) instead of the HLK-PM01 ?
If this is a working solution, it would make your project even cheaper.

An other question on the DS18B20. Wont the proximity with the relays (heat generators) will disturb the temperature reading ?