DIY Home Automation – Iteration 3

The goal of this series is to document the developments in DIY Home automation. This post describes iteration 3, focussing on optimizing the first smart thing: A sourdough proofing box. Read iteration 2 here, which was about setting up the mqtt server and the first smart thing connection.

Now that the Home Assistant and Mosquitto mqtt servers are running and connected, it is time to improve the system. The first step was to measure the room temperature every 10 minutes. This is working properly, but now it is time to add a proper device to the system. Another thing on my Make101 list is to create a sourdough starter and bake sourdough bread. So far I have unsuccessful, the starter always dies after some days 🙁

I strongly believe that this is because the temperature is too low during the night. I tried several tricks (like putting it on top of the fridge, where heat is always present), but so far I have been unsuccessful. Time to make this a smart: the smart proofing box! This box is nothing more than an insulated cube with a light inside. When the light is turned on, it will generate the heat needed for the sourdough starter. When the light is off, the box will cool down. To make it work the controller needs to start up, measure the temperature and act on the result (do nothing, turn off or turn on the light).

This is what the proofing box should do every 10 minutes:

* Wake up
* Measure the current temperature
* Send the datapoint to the Home Automation MQTT server
* Turn the light on or off
* Go to deep sleep