Automatic Irrigation

Raspberry Pi script for automatic irrigation based on weatherstation data.

Python script to be launched preferably during night time
Reads Weatherstation data of past days from WeeWX database
Calculates with Makkink formula the net evaporation (evaporation - rain - watering)
Maintains database of amount of watering done
Steers relay boards on Raspberry Pi to open and close valves
Supports multiple water sources (barrel, drinking water)
Supports multiple irrigation zones with area (m2), shadow (%), flow requirements (drip or sprinkler system)
Measures the flow rate to calculate liters of watering
Writes the amount of millimeter watered in database

Still in beta phase; all parts functional, but needs to be finetuned.

Electronic circuit used

See https://github.com/EdwinGH/automatic-irrigation/blob/main/circuit.png

Dependencies

The following packages are needed:

python3-mysql.connector
python3-numpy Also for mailing the results (see the crontab) the msmtp package was installed

How to run

Crontab on Raspberry Pi to start and monitor the process:

0  7   *   *   *   /usr/bin/python3 /home/pi/irrigation/daily-irrigation.py -l debug -f /home/pi/irrigation/daily-irrigation.log -s 192.168.10.10 -u USER -p Pass |/usr/bin/mail -s "Pi Irrigation result" user@host
0  8   *   *   *   OUTPUT=`/bin/ps -eaf |grep -i irrigation |grep python|grep -v sh` && echo "$OUTPUT" | /usr/bin/mail -s "Pi Irrigation running" user@host
0  9   *   *   *   /usr/bin/pkill -f 'irrigation' && /usr/bin/mail -s "Pi Irrigation Killed process" user@host`

So irrigation starts at 7AM, with MySQL Weewx weather database on 192.168.10.10 and username USER and password Pass. It captures debug messages locally in a file, and sends a mail to user@host with the normal output. At 8AM it sends a mail if still running And at 9AM it sends a graceful SigTerm to close the valves (with SystemExit exception handling in the Python code).