Water your plants with a Raspberry Pi
Conclusions
For all three plant pots, I finally had to determine empirically the limit values of all combinations of plant and pot soil and substrate (Listing 4). A fourth sensor, which Figure 1 does not show, was finally placed in the water tank. It is monitored by its own thread starting in line 124 of Listing 3; the budding digital gardener has to connect the red cable to another free GPIO port on the Raspberry Pi Zero. If there is no water in the tank, the script sends email and blocks the other threads until the plant owner gets round to refilling the tank (Listing 3, lines 130-136).
The data for the tank sensor can be found in the YAML file in the tank
block (Listing 4, lines 36-40), and the email parameters are in the mail
block (lines 42-45). Depending on the configuration of your local email system, you might need to adjust the code so that it contains more detailed information with a clear-cut subject line to keep it from ending up in the Spam folder. The configuration file also contains the debug
parameter (line 53), which makes the script more verbose at runtime.
For larger plant containers, such as a flower box, several sensors and water supply systems would have to be used in each box. Here again, some experimentation would be necessary to achieve the desired average soil moisture. Meanwhile, the scripts enter the measured values into an Influx database (Listing 3, lines 39-55). On the basis of this database, it is then possible to obtain an overview (e.g., with Grafana), so you can better adjust the parameters after analysis.
Infos
- "The sys admin's daily grind – PomodoPi" by Charly Kühnast, Linux Pro Magazine, issue 177, August 2015, pg. 56: https://www.linuxpromagazine.com/Issues/2015/177/Charly-s-Column-PomodoPi
- Irrigation kit: https://www.amazon.com/WayinTop-Automatic-Irrigation-Watering-Capacitive/dp/B07TMVNTDK/
- Adafruit Python library for MCP3008: https://github.com/adafruit/Adafruit_Python_MCP3008
- Raspberry Pi Zero W: https://www.raspberrypi.org/products/raspberry-pi-zero-w/
- Fritzing: https://fritzing.org/home/
- GPIOs: https://www.raspberrypi.org/documentation/usage/gpio/
- Attribution-ShareAlike 4.0 International: https://creativecommons.org/licenses/by-sa/4.0/
- Code for this article: ftp://ftp.linux-magazine.com/pub/listings/linux-magazine.com/236/
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