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.
![](/var/linux_magazin/storage/images/issues/2019/225/charly-s-column-mi-flora/figure-12/754047-1-eng-US/Figure-1_large.png)
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.
Recording the Weather with Bluetooth
The next step is to scan the environment for Bluetooth transmitters. This can usually be done with the command
sudo hcitool scan
but since the sensor is capable of low-energy transmission, I did the scan by typing:
sudo hcitool lescan
The result was a list of MAC addresses and the short names of nearby devices that can speak Bluetooth Low Energy. Hey presto, one of them was my sensor:
[...] C4:7C:8D:6A:5E:17 Flower care
Now I have the MAC address and want to see if the sensor is sending any data:
sudo gatttool --device=C4:7C:8D:6A:5E:17--char-read -a 0x35
The feedback doesn't need to mean anything to me at first glance:
Characteristic value/descriptor: aa bb cc dd ee ff 99 88 77 66 00 00 0000 00 00 00
The important thing is that there is a response at all, because on GitHub there is a small tool that can interpret the data from the sensor. I cloned it to my current directory, as follows:
git clone https://github.com/open-homeautomation/miflora.git
The package contains a small Python script by the name of demo.py
, which reads and displays different measured values from the sensor. Now let's run it:
python3 /home/pi/miflora/demo.py--backend gatttool pollC4:7C:8D:6A:5E:17
Voila! The output looks good:
Getting data from Mi Flora FW: 3.2.1 Name: Flower care Temperature: 23.0°C Moisture: 40 Light: 193 Conductivity: 247 Battery: 100
The humidity is given as a percentage and the luminous intensity in lux. The Conductivity
is shown in microsiemens – it indirectly says something about the nutrient content of the soil.
That's the full extent of my electronic green thumb (at the moment, Figure 2), and I'm already looking forward to the grand opening of my salad bar.
Infos
- "Pomodo Pi" by Charly Kühnast, Linux Magazine, issue 177, August 2015, http://www.linux-magazine.com/Issues/2015/177/Charly-s-Column-PomodoPi/(language)/eng-US
Buy this article as PDF
(incl. VAT)
Buy Linux Magazine
Subscribe to our Linux Newsletters
Find Linux and Open Source Jobs
Subscribe to our ADMIN Newsletters
Support Our Work
Linux Magazine content is made possible with support from readers like you. Please consider contributing when you’ve found an article to be beneficial.
![Learn More](https://www.linux-magazine.com/var/linux_magazin/storage/images/media/linux-magazine-eng-us/images/misc/learn-more/834592-1-eng-US/Learn-More_medium.png)
News
-
Canonical Offers 12-Year LTS for Open Source Docker Images
Canonical is expanding its LTS offering to reach beyond the DEB packages with a new distro-less Docker image.
-
Plasma Desktop 6.1 Released with Several Enhancements
If you're a fan of Plasma Desktop, you should be excited about this new point release.
-
SUSE Offers CentOS 7 Support with Liberty Linux Lite
SUSE's Liberty Linux support offering now includes CentOS 7, which means businesses won't be forced to migrate those servers for some time.
-
Ubuntu's App Center Finally Supports Local Installs Again
If you regularly download .deb files and would prefer a GUI method of installing, Ubuntu has your back.
-
AlmaLinux Now Supports Raspberry Pi 5
If you're looking to create with the Raspberry Pi 5 and want to use AlmaLinux as your OS, you're in luck because it's now possible.
-
Kubuntu Focus Releases New Iterations of Ir14 and Ir16 Laptops
If you're a fan of the Kubuntu Focus laptops or have been waiting for the right time to purchase one, that time might be now.
-
NixOS 24.05 Is Ready for Prime Time
The latest release of NixOS (Uakari) has arrived and offers its usual reproducible, declarative, and reliable goodness.
-
Linux Lite 7.0 Officially Released
Based on Ubuntu 24.04 and kernel 6.8, Linux Lite version 7 now offers more options than ever.
-
KaOS Linux 2024.05 Adds Bcachfs Support and More
With updates all around, KaOS Linux now includes support for the bcachefs file system.
-
TUXEDO Computers Unveils New Iteration of the Stellaris Laptop Line
The Stellaris Slim 15 is the 6th generation and includes either an AMD or Intel CPU