The sys admin's daily grind: Mi Flora sensors
Salad Grower
Columnist Charly Kühnast recently attached Mi Flora humidity sensors to his potted plants. At first, they only transmitted junk on Bluetooth, but armed with the right tools and a Rasp Pi, Charly now reaps a rich harvest of data.
A long time ago, I wrote about my little Pomodo Pi project [1] in this magazine. It involved me monitoring my tomato plant's soil humidity and watering the plants when there was a risk of them drying out by automatically opening a solenoid valve when the humidity dropped below a certain value. The Vegetronix sensors I still use for this are high quality and durable, but, unfortunately, they need an extra A/D converter and wiring them involved some tinkering.
Meanwhile, I have bought some humidity Mi Flora plant sensors (Figure 1). Their manufacturer, Xiaomi, envisages sending the data to a smartphone app, but I never bothered installing it; instead I pick up the data directly via Bluetooth.
I run the whole thing on a Raspberry Pi, but of course any Linux PC equipped with Bluetooth hardware will do. Software-wise you need the bluez, python3, and python-pexpect packages, which are quickly installed.
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