A Raspberry Pi post for Pi day

I’ve recently fallen in love with Raspberry Pi computers again. The discovery of MQTT and io.adafruit.com for data logging lead me to Node Red.

Node Red is awesome! It’s like scratch programming for things!

Monitoring a fridge is as simple as drawing a few lines between some boxes.

For example. My fridge is starting to have some issues. It wants to keep freezing everything in the fridge. It dials the temperature setting all the way up and we don’t know why. I’ve taken the fridge apart as best as I can the last time we defrosted it just to wiggle all the wiring connections.

A quick gauge showing me the current fridge and freezer temp.

I wanted to really see what was going on with the fridge. I grabbed a Raspberry Pi Zero W and a couple of 1 wire digital thermometers and put together a Fridge monitoring system in a couple of hours. I can now see what happens with my fridge. It does a defrost sequence and comes out of it cold, freezing up the fridge.

I made my own ‘flat’ wires from some old phone wire and electrical tape. This allows the doors to still close and seal around the wires.
With the Raspberry Pi hiding underneath this ‘hat’ or ‘bonnet’ circuit board, the electronics doesn’t look like much. A pair of one wire (really 3) temperature probes and a pull-up resistor. Crazy simple.

A quick dashboard configuration, and I now have a view of the current temperature and a graph of the temperature history.

Hey, something changed! I removed a beverage allowing the cold air from the freezer to hit the temperature probe directly and show a wider temperature swing.

Add a couple of more nodes and I now get email notifications when the fridge is too cold. Another node, and the Google Home announces the too-cold temperature.

My fridge now complains that it is cold.

How epic is that? Under $20 worth of parts to give my fridge a voice.

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