Raspberry Pi Balcony Irrigation Controller

Python code for my Raspberry Pi to control the watering of plants on my balcony.

This is part of the Oh, Balcony! project.

The software allows the control of one or multiple pumps (to pump water from a water tank), valves (to control the flow of water through a system of water hoses), soil moisture sensors (for measuring whether plants should be watered), water level sensors (for measuring the water level in a water tank) and temperature sensors.

Prerequisites

If you haven't installed an Operating System on your Raspberry Pi then follow my instructions here: Raspberry Pi Installation

The following additional software packages will be required:

Python 3:

sudo apt install python3

Python requests HTTP library:

sudo apt install python3-requests

Python gpiozero library:

sudo apt install python3-gpiozero

Python w1thermsensor library:

sudo apt install python3-w1thermsensor

Python spidev library, which is needed for hardware accelerated SPI. It will also work without, but reading Soil Moisture sensors through an MCP3008 Analog-Digital Converter (ADC) will be a little slower (I measured 1.4ms instead of 0.04ms per reading):

sudo apt install python3-spidev

Additionally the SPI kernel module will need to be enabled. Start the Raspberry Pi configuration tool with

sudo raspi-config

and select Interfacing Options and then SPI.

If a 1-wire temperature sensor (DS18S20, DS1822, DS18B20, DS28EA00, DS1825/MAX31850K) is used, then enable also the 1-wire interface. For that add the following line to the file /boot/config.txt:

dtoverlay=w1-gpio,gpiopin=4,pullup=on

Note: the pullup=on is required if you connected the sensor with a parasitic circuit (GND and VDD connected) as described by Martin Kompf. With a non-parasitic circuit it is not needed, as described by Adafruit.

Afterwards the Pi will need to be rebooted for the configuration changes to take effect.

Usage

Clone the git repository:

git clone https://github.com/oh-balcony/oh-raspi.git

Configuration

Copy the file config.sample.py to config.py and adapt it to your needs.

Testing

To manually test reading sensor values and turning on/off irrigation, start in testing mode:

./test.sh

Starting

Run:

./main.py

Autostart

To automatically start the script when the Raspberry Pi is rebooted, execute:

crontab -e

... and then add the following line to the crontab:

@reboot sleep 5 && /home/pi/scripts/oh-raspi/start.sh

(Replace the full path to the script with the location where you installed it.)

Logrotate

To avoid that the log file grows infinite create the following logrotate rule as /etc/logrotate.d/oh-raspi:

/home/pi/scripts/oh-raspi/oh-raspi.log {
   weekly
   rotate 4
   compress
   missingok
   copytruncate
}

(Replace the path of the logfile with the location where you installed it.)