SENSORS/ACTUATORS

Raspberry Pi - Water/Liquid Valve

This tutorial instructs you how to use a Raspberry Pi and a solenoid valve to control the flow of liquids such as water, beer, and oil. The same principles apply to controlling gas flow.

Hardware Preparation

1	×	Raspberry Pi 4 Model B
1	×	Relay
1	×	Liquid Solenoid Valve
1	×	12V Power Adapter
1	×	DC Power Jack
1	×	Jumper Wires
1	×	(Optional) Screw Terminal Adapter for Raspberry Pi

Or you can buy the following sensor kits:

1	×	DIYables Sensor Kit (30 sensors/displays)
1	×	DIYables Sensor Kit (18 sensors/displays)

Disclosure: Some of the links provided in this section are Amazon affiliate links. We may receive a commission for any purchases made through these links at no additional cost to you. We appreciate your support.

Overview of Water/Liquid Valve

The Water/Liquid Valve Pinout

A Solenoid Valve generally has two terminals:

The Positive (+) pin (red) should be connected to 12V of a DC power supply
The Negative (-) pin (black or other) should be connected to the GND of a DC power supply

How Water/Liquid Valve works

Typically, the valve is shut. When 12V DC is supplied to the two terminals, the valve opens and water/liquid can pass through.

※ NOTE THAT:

A gasket arrangement is present inside, thus requiring a minimum pressure to open the valve after 12V DC is applied. This pressure can be generated by liquid flow.

How to Control Water/Liquid Solenoid Valve using Raspberry Pi

If the valve is supplied with 12V, it will open. In order to control the valve, a relay needs to be used between Raspberry Pi and the valve. Raspberry Pi can manage the solenoid valve through the relay.

If you are not familiar with the relay (pinout, how it works, how to program, etc.), then check out the Raspberry Pi - Relay tutorial for more information.

Wiring Diagram

This image is created using Fritzing. Click to enlarge image

Raspberry Pi Code for Controlling Liquid Valve

The code below turns the water valve ON and OFF every five seconds.

Detailed Instructions

Make sure you have Raspbian or any other Raspberry Pi compatible operating system installed on your Pi.
Make sure your Raspberry Pi is connected to the same local network as your PC.
Make sure your Raspberry Pi is connected to the internet if you need to install some libraries.
If this is the first time you use Raspberry Pi, See how to set up the Raspberry Pi
Connect your PC to the Raspberry Pi via SSH using the built-in SSH client on Linux and macOS or PuTTY on Windows. See to how connect your PC to Raspberry Pi via SSH.
Make sure you have the RPi.GPIO library installed. If not, install it using the following command:

sudo apt-get update sudo apt-get install python3-rpi.gpio

Create a Python script file valve.py and add the following code:

# This Raspberry Pi code was developed by newbiely.com # This Raspberry Pi code is made available for public use without any restriction # For comprehensive instructions and wiring diagrams, please visit: # https://newbiely.com/tutorials/raspberry-pi/raspberry-pi-water-liquid-valve import RPi.GPIO as GPIO import time # Set the GPIO mode (BCM or BOARD) GPIO.setmode(GPIO.BCM) # Define the GPIO pin controls the water valve via the relay module RELAY_PIN = 12 # Set the relay pin as an output pin GPIO.setup(RELAY_PIN, GPIO.OUT) try: # Run the loop function indefinitely while True: # Turn the relay ON (HIGH) to turn on the water valve GPIO.output(RELAY_PIN, GPIO.HIGH) time.sleep(5) # Wait for 5 seconds # Turn the relay OFF (LOW) to turn off the water valve GPIO.output(RELAY_PIN, GPIO.LOW) time.sleep(5) # Wait for 5 seconds except KeyboardInterrupt: # If the user presses Ctrl+C, clean up the GPIO configuration GPIO.cleanup()

Save the file and run the Python script by executing the following command in the terminal:

python3 valve.py

Check out the water flow.

The script runs in an infinite loop continuously until you press Ctrl + C in the terminal.

Code Explanation

Check out the line-by-line explanation contained in the comments of the source code!

Video Tutorial

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