Open Rain

DIY irrigation system with a Raspberry Pi. Two modes:

1. On demand watering via a web interface.
2. Custom regular watering with a cron job.

→ This project is supposed to be run on a Raspberry Pi. On a standard computer, you can still run a demo of the web interface.

EDIT: The system operated autonomously for two months in a dry and hot environment, and we were pleased to discover plenty of vegetables, which would have been wiped out in the scorching sun without Open Rain!

Table of contents

• Installation
  • Basic installation
  • MySQL server
  • Secret key for authentication
• Irrigation system
  • Main hardware components
  • Schema of the whole system
  • Pin configuration
• Option 1: on demand watering via a web interface
  • Options
  • Hosting the website
  • Raspberry Pi
  • Standard computer
• Option 2: custom regular watering with a cron job
• Access the GPIO pins without root

Installation

Basic installation

Note: The basic installation is sufficient to run the second option (regular watering with a cron job, detailed here).

Clone the project in your current location, and navigate to it:

git clone https://github.com/bloodymosquito/open-rain.git
cd open-rain

This project use python3 with the libraries listed in requirements.txt.

For instance, you may create a python3 virtual environment with virtualenv:

virtualenv -p python3 ~/.virtualenvs/openrain
source ~/.virtualenvs/openrain/bin/activate
pip install -r requirements.txt

Note: For the first option (on demand watering via a web interface), you also need the following steps.

MySQL server

To run the web server, you need MySQL. Here is a tutorial to install it on Ubuntu.

Then, setup a MySQL database for the openrain web server:

python mysql_setup.py

It creates a MySQL user called admin_openrain, a database called openrain with a table users containing the admin user for the website.

Secret key for authentication

The web server uses a secret key for authentication and security. Create the text file ./config/cookie.secret, and write a long random sequence of characters on the first line.

Irrigation system

Main hardware components

• A Raspberry Pi.
• A solenoid valve.
• A relay module.
• An ultrasonic sensor.
• Two resistors (1000 and 2000 ohms): we use a voltage divider to reduce the ultrasonic sensor's 5V output to 3.3V (for the Raspberry Pi).
• A water container, filled with rainwater.
• Drip irrigation material.

Schema of the whole system

Pin configuration

In the file config/pins.json, report the GPIO pins you used for:

• The trigger pin of the ultrasonic sensor (here GPIO18).
• The echo pin of the ultrasonic sensor (here GPIO24).
• The IN pin of each relay (here GPIO2).

If you have a module with multiple relays, you can build several independent irrigation circuits. Here is an example of config/pins.json with eight relays:

{
    "relay":
    {
        "1": 2,
        "2": 3,
        "3": 4,
        "4": 17,
        "5": 27,
        "6": 22,
        "7": 10,
        "8": 9
    },
    "trigger": 18,
    "echo": 24
}

Option 1: on demand watering via a web interface

To run the web interface, type:

python server.py

It will prompt for the password of the MySQL admin_openrain user, that you defined when using the mysql_setup.py script in MySQL server section.

In your browser, type localhost:9080 to access the website.

For the first time, enter the user admin with the password you defined when using the mysql_setup.py script.

Once logged in, you can resort to the create user section to add a new user to the database.

Options

• You can specify the dimensions of your (cylindrical) water container with the options --height and --diameter.
• You can change the port with the --port option.

Type python server.py -h to see all the options.

Hosting the website

You can then do port forwarding on your router to host the website on your Raspberry Pi and make it accessible from the internet.

Raspberry Pi

When running this script on a Raspberry Pi:

• The slider Watering circuit n°1 button will change the state of the relay to start / stop watering.
• The measure button will measure the remaining volume of water in the container.

Standard computer

To run a demo of the web interface on a computer, type python server.py. As there is no GPIO pins, the behaviour is simulated. In particular:

• The slider Watering circuit n°1 button will move but does nothing concrete.
• The measure button will provide random values.

Option 2: custom regular watering with a cron job

If your Raspberry Pi doesn't have access to the internet, or if you want to automate the watering, you can use the script cron.py, with the job scheduler of your OS, for instance cron for Unix-like systems.

Type crontab -e to edit the cron jobs.

A line in crontab looks like: * * * * * command to execute

With the five stars corresponding to:

1. minute (0 - 59)
2. hour (0 - 23)
3. day of the month (1 - 31)
4. month (1 - 12)
5. day of the week (0 - 6)

For instance, to do watering every night at 1 a.m., type:

0 1 * * * ~/.virtualenvs/openrain/bin/python /path/to/openrain/cron.py

You can add optional arguments (described below) in this line too.

Options

• You can specify the number of liters to use with the --liters argument (default: 5).
• If it rained (positive variation of the container volume), then this script won't do watering. You can specify the threshold of detection of a rain (in liters) with the --rain_volume argument.
• There is a limit duration of watering for security, you can modify it via the --time_limit argument.

Type python cron.py -h to see all the options.

Access the GPIO pins without root

On a Rapsberry Pi, the scripts server.py and cron.py should be run as root to access the GPIO pins. You can change it as explained in this discussion.