Hi All,
Im a complete novice to microcontrollers, and know a bit about home assistant. I have read that the RP2040 has an inbuilt temperature sensor and I would like to attempt to have it connect to home assistant for automation and monitoring. Does anyone know the best way to do this?
It’s measuring chip temperature - so not so useful. It is also on an internal ADC - ADC4, which I believe is not available as a GPIO in ESPHome.
There are examples on the net that demonstrate reading it, if you can get data from it you apply the formula below to the voltage reading:
T = 27 - (ADC_voltage - 0.706)/0.001721
That will supposedly give you the temperature in °C.
Good luck 
and let us know if you get it to work. Maybe someone else has already done it (or attempted it) that can add more.