A couple of weeks ago I had the unfortunate problem of my freezer’s auto-defrost not kicking on an the coils freezing completely. This led to my fridge not cooling down past 60. I had to take apart my freezer for the first time to de-ice the coils to get it working again. Then I got the bright idea of using some of the spare temperature probes I have and a spare Pi to monitor temperature. So I wired up a Pi and created a dashboard for monitoring temperatures in Grafana out of a postgres database.
Wiring was really simple, I just followed this guide to wire multiple probes up: https://www.hackster.io/vinayyn/multiple-ds18b20-temp-sensors-interfacing-with-raspberry-pi-d8a6b0
Code looks like this: https://gitlab.com/-/snippets/2491465
A couple of minutes in grafana and I get some cool graphs like this:
Now I can see the defrost cycle kicking in and monitor the average temperatures. I just went shopping so the freezer is a bit higher than it should be, but should be coming down soon. I still need to work on the door seals but I don’t feel any cold air coming through them with the probes just taped up inside.