I set up a raspberry pi thermometer in our freezer that would email me once a day with a temperature log (hourly averages), and also email me immediately if the temperature ever got too high. But dammit, I opted in for those emails!
(It was a freezer full of the most precious commodity, breast milk. And it actually did save us one time when the freezer thermostat failed, so it was absolutely worth the hassle.)
Ha! Last time I tried putting a rpi into a fridge… for cooling - it broke because of the humidity :)
Should’ve used the freezer.
Oh I only put the actual temperature sensor inside. Ran some thin wires out to the pi under the door gasket.
I use this wireless fridge/freezer thermometer [1]. The units that go in the fridge and freezer communicate with the display unit via 433 MHz RF.
I have an RTL-SDR [2] on the RPi.
I run rtl_433 [3] on the RPi. rtl_433 understands the protocols of a large number of wireless sensors, including the ones used by those AcuRite sensors.
I've got it configured to output whatever sensor data it decodes in JSON format to a file, and a script that periodically parses new entries from that file and records in an sqlite DB the readings from the sensors I'm interested in.
Rtl_433 is a fun program. It recognizes and decodes the transmissions of a lot of things. It is getting several neighbor's wireless thermometers and humidity sensors, a soil moisture sensor, several different car tire pressure sensors, a smoke detector, some kind of keypad (wireless lock?), a car remote, some kind of energy monitor, a rain gauge, and a wind speed/direction sensor.
[1] https://www.amazon.com/gp/product/B004QJVU78/