Requirements

The requirements listed below are the one used for the development of pih2o, but other configuration may work fine.

The pump can be replaced by an electro valve if the tank water is upper than the plants (watering by gravity). The number of soil moisture sensors can be easily adapted from 1 to 4. The transistor is optional, the sensors can be directly connected to the 5V pin in order to power them continuously (but it accelerate their corrosion).

Install

A brief description on how to set-up a Raspberry Pi to use this software.

1. Download latest Raspbian image and set-up an SD-card. You can follow these instructions .

2. Insert the SD-card into the Raspberry Pi and fire it up. Use the raspi-config tool that is shown automatically on the first boot to configure your system (e.g., expand partition, change hostname, password, enable SSH, configure to boot into GUI, etc.).

3. Reboot and open a terminal. Install the latest firmware version:

   $ sudo rpi-update

4. Upgrade all installed software:

   $ sudo apt-get update
   $ sudo apt-get upgrade

5. Install pih2o from the pypi repository:

   $ sudo pip3 install pih2o

Run

Start the automatic plant watering application using the command:

$ pih2o

The application acts as a daemon running on the Raspberry Pi. It can be controlled thanks to an RESTful API.

The pih2o is scheduled to wake up every given interval, power the soil moisture sensors and take humidity measurement (or threshold if no analog input available). Finally the sensors are powered off to extend their lifespan.

                  ┌───────────── minute (0 - 59)
                  │ ┌───────────── hour (0 - 23)
                  │ │ ┌───────────── day of month (1 - 31)
                  │ │ │ ┌───────────── month (1 - 12)
                  │ │ │ │ ┌───────────── day of week (0 - 6) (Sunday to Saturday)
                  │ │ │ │ │
                  │ │ │ │ │
record_interval = * * * * *

Install developing version

If you want to use an unofficial version of the pih2o application, you need to work from a clone of this git repository. Replace the step 5. of the Install procedure above by the following actions:

• clone from github

  $ git clone https://github.com/anxuae/piH2O.git

• go in the cloned directory

  $ cd pih2o

• install pih2o in editable mode

  $ sudo pip3 install -e .

• start the application exactly in the same way as installed from pypi. All modifications performed in the cloned repository are taken into account when the application starts.

Configuration

At the first run, a configuration file is generated in ~/.config/pih2o/pih2o.cfg which permits to configure the behavior of the application. The configuration can be easily edited using the command:

$ pih2o --config

The default configuration can be restored with the command (strongly recommended when upgrading pih2o):

$ pih2o --reset

See the default configuration file for further details.

Circuit diagram

Soil moisture sensor specification used for this project (the number is up to you but the following diagram is for up to 4 max):

Digital sensors

Here is the diagram for digital sensors (rise to high on dry soil). Depending on the sensor type, an signal amplifier may be necessary (not represented on this diagram).

Analog sensors

Here is the diagram for analog sensors connected to an ADC1115 to measure humidity level.

Pump

Here is the diagram for the pump (or electro valve). For better understanding the sensors are not represented here.