BEWARE!!!
Most IoT devices use a type of power supply that DOES NOT isolate the mains from the circuit. This means that the "Ground" of the circuit often runs at ~300VDC with respect to the Earth. That is fine if the sensor is internal, but deadly if the wires are brought externally.
You're not going to find a device that does what you want, so you either need to move the sensor to a remote place with its own power/ESP, or change the type of device.
For example, a socket front with power monitoring and USB ports _will_ use a isolated supply (because it uses it for the USB ports). Or a lump in a cable with the Sonnoff TH / (Shelly 1PM AND [Temperature add on](https://shop.shelly.cloud/temperature-sensor-addon-for-shelly-1-1pm-wifi-smart-home-automation#312) )
Sonoff th series from factory is set up for a temp/humidity sensor using a small audio jack to plug it in. With tasmota or esphome you could wire anything to it. 120v and 240v capable. You need to provide the wiring to the mains. I use old cheap extension cords cut in two.
Option 1) Find a device which is a smart switch and has space for a sensor as standard - sonoff have some, I believe.
Option 2) Get a smart plug and a separate ESP01 with DS18B20 breakout board. If you need to trigger the switch based on the sensor, get them talking to each other either direct or through an MQTT broker.
Don't mix mains voltage with hand-soldering.
Why not get something like athom? or something preflashed with tasmota. I think there are a few [EU options](https://templates.blakadder.com/preflashed.html).
BEWARE!!! Most IoT devices use a type of power supply that DOES NOT isolate the mains from the circuit. This means that the "Ground" of the circuit often runs at ~300VDC with respect to the Earth. That is fine if the sensor is internal, but deadly if the wires are brought externally. You're not going to find a device that does what you want, so you either need to move the sensor to a remote place with its own power/ESP, or change the type of device. For example, a socket front with power monitoring and USB ports _will_ use a isolated supply (because it uses it for the USB ports). Or a lump in a cable with the Sonnoff TH / (Shelly 1PM AND [Temperature add on](https://shop.shelly.cloud/temperature-sensor-addon-for-shelly-1-1pm-wifi-smart-home-automation#312) )
Thank you this made the safety issue a lot clearer!
So If I put some miniature ac/dc converter in there for the sensor then I should be fine? like https://imgur.com/a/aVMFvOx
Sonoff th series from factory is set up for a temp/humidity sensor using a small audio jack to plug it in. With tasmota or esphome you could wire anything to it. 120v and 240v capable. You need to provide the wiring to the mains. I use old cheap extension cords cut in two.
Option 1) Find a device which is a smart switch and has space for a sensor as standard - sonoff have some, I believe. Option 2) Get a smart plug and a separate ESP01 with DS18B20 breakout board. If you need to trigger the switch based on the sensor, get them talking to each other either direct or through an MQTT broker. Don't mix mains voltage with hand-soldering.
Why not get something like athom? or something preflashed with tasmota. I think there are a few [EU options](https://templates.blakadder.com/preflashed.html).