FlowerCare and Nymea to Rescue My Plants

Getting hands dirty on hooking up plant care sensors to my existing open source smart home. A walkthrough on plugin development for nymea.
The storyAs many other tinkerers and hackers, I’m suffering too from the issue that hacking on things takes up so much of my time that I occasionally forget to water my plants. After my Monstera Deliciosa once again suffered from dry soil, I decided to see whether I can do something about it to remind me when it’s thirsty.
A quick research on the web brought my attention to the Xiaomi FlowerCare, also known as MiCare or PlantCare. It is a Bluetooth Low Energy device and some basic research revealed that its protocol seem to be quite easy to understand. While Xiaomi doesn’t seem to provide any public specs, there has been quite a bit of reverse engineering on the internet for this device yet. So I decided to order one of those.
A few days later it got delivered and of course I started to play around with it right away. I briefly checked out the app that comes with it but as you probably can guess, using it in its default setup was never my plan. Of course this needs to be integrated with my existing smart home setup.As also described here I’m using nymea as my smart home solution (Yes, you can even spot the Monstera in one of the pictures there :)). Sadly, nymea didn’t support that sensor yet so firing up some IDE was in order.”