Elizabeth from Git Tech’d has shown us how to monitor freezers and fridges remotely with a temperature sensor and Raspberry Pi. A real-time temperature monitor dashboard lets you keep an eye on things, and text message alerts can be set up to let you know when the temperature is rising.
The idea came about after Rick Kuhlman‘s wife lost a load of breast milk she had stored in the freezer. To make sure that months of hard work was never wasted again, Rick came up with this $30 solution.
- Raspberry Pi Zero W
- Adafruit BME280 sensor — an integrated temperature and humidity sensor
- Hammond Miniature ABS Enclosure — used to enclose and mount the sensor inside the freezer
- Flat Flex cable — only the flattest cables can bridge the seal of a freezer without causing an air leak
Easy does it: you just wire the temperature sensor directly to your Raspberry Pi. Rick has even made you a nice wiring diagram, so no excuses:
There’s a little fiddling to make sure your Flat Flex cable attaches properly to the temperature sensor. The project walkthrough provides a really clear, illustrated step-by-step to help you.
Everything looks pretty simple according to the installation walkthrough. A couple of Python libraries accessed via Raspberry Pi OS and you’re there.
You’ll need an access key from Initial State, but Rick explains you can get a free trial. The real-time temperature monitor dashboard is hosted on your Initial State account. If you want to have a poke around one that’s already up and running, have a look at Rick’s dashboard.
You can configure your own alert parameters from within the dashboard. Set your desired temperature and how much leeway you can tolerate.
You’ll get a text alert if the temperature falls too far above or below your personal setting.
We can see this affordable fix helping out science labs that need to keep their expensive reagents cold but don’t have the budget for freezers with built-in monitoring, as well as people who need to keep medication at a certain temperature at home. Or maybe food outlets that don’t want to risk losing loads of pricy perishables stacked up in a chest freezer. Nice work, Rick and Elizabeth!