This is a capacitive type Soil Moisture with digital output, designed to be directly connected to the Raspberry PI GPIO or other digital controllers. It can be used with the open source irrigation software Hydrosys4, or with your own project using the python script provided in the link below.

Python script to read the sensor data

Hydrosys4 Software

The sensor measures the moisture in the soil, this data can be used to control the irrigation time and duration. Multiple sensors can be used with same raspberry PI, each sensor requires its GPIO PIN. The Sensor is provided as in the below picture. In the base version, the circuitry in the upper part of the sensor is not water resistant, so it needs to be protected in case it is exposed to water. The water resistant version is protected from the water and can be directly placed outdoor.

In the upper right part of this page it is possible to select the water resistant option.

What is in the package:

Video Showing the product here:

The package will include the Sensor as in the picture.

If the water resistant option is selected, the Sensor will arrive with a cover for the electronics and 1.5 meters cable (4.9 foot). Below a picture of the water resistant version:

In case you chose the option non water resistant, an easy way to waterproof the electronic part of the Sensor is by covering it with standard silicone sealant.

The Hardware:

Connections:

• Connector PIN type (2.54 pitch) with 3 pins: VCC (+5v) , GND , DAT.
• VCC should be connected to 5v.
• DAT should be connected to a GPIO pin.
• GND should be connected to the ground.

The Software

It can be integrated in any project which can import data from a python module, the python file is in the Github repository as linked above. The sensor can also be used with the hydrosys4 SW, the open source irrigation software for Raspberry Pi.

Setting the Hydrosys4 SW to use the sensor

STEP 1: To add the Sensor to the list of the hardware. In the hydrosys4 menu, go to the "hardwareSetting" page and click "edit". In the "Add" row (first row) Set the parameters as in the below picture, "name" and "pin" should be changed according to your implementation. PIN field should be the GPIO pin number where the sensor is connected (please ensure that the PIN is not already used in other rows of the table). Click "Add" to add the row in the table, to finish click "Confirm and Save"

STEP 2: Test if things work, go to "Setting" page, in the section "Sensor Data" and click on the "read" button corresponding to the assigned sensor name. You should be able to see a number.

For Sensor calibration and Setting in hydrosys4, please refer to the video below.

Youtube: Soil Moisture Sensor and Automatic Irrigation

Web Page: Irrigation Setup Instructions

WiFi and Solar

The sensor can be connected to the WiFi using the ESP device, If you want to learn more about it, you can see the video below. I also powered it by Solar to make it completely wireless.

Wifi Connected - solar powered sensors

NOTE

The sensor is sensitive to the spurious frequencies in your power supply system, in some cases it has been reported that if led lights or motors are connected to the same power system, they might alter the reading. In such case try to use a separate power for the LED and the Sensor.

After the sensor is placed in the soil it requires a couple of days to stabilize the reading. You will see a curve like this:

The Sensor placement in the ground is very important, once placed into the soil, push the surrounding land to compact it and ensure the contact of the soil with the Sensor.

NOTE: Please pay attention to not scratch the sensor surface, this will drastically reduce the life of the sensor.

Documentation

Example of field data:

Hydrosys4 system website:

For more info you can refer to website: Hydrosys4 website