The sys admin's daily grind: Mi Flora sensors

Salad Grower

Article from Issue 225/2019

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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