Using the PM as a thermometer
I wired up a DS1621 digital thermometer IC to the PM. With this IC it’s possible to measure the temperature very easily.
I communicate with the sensor using the same I²C bus functions as for EEPROM access (just one small additional function). The sensor outputs the temperature as 9 bits of data.
The black IC in front is wired to the PM using magnet wire.
My cheap clock/thermometer agrees with the DS1621.
Included in the zip file are instructions to wire up the sensor to the PM, so you can add a temperature sensor to your PM too (and read the temperature if you’ve got a flashcart 
).