SENSORS/ACTUATORS

Raspberry Pi Pico - Water/Liquid Valve

This tutorial instructs you how to control liquid flows such as water, beer, and oil using a Raspberry Pi Pico and a solenoid valve. We will cover:

How to connect the solenoid valve with Raspberry Pi Pico
How to code Raspberry Pi Pico to control the valve.

Hardware Preparation

1	×	Raspberry Pi Pico W
1	×	Raspberry Pi Pico (Alternatively)
1	×	Micro USB Cable
1	×	Relay
1	×	Liquid Solenoid Valve
1	×	12V Power Adapter
1	×	DC Power Jack
1	×	Jumper Wires
1	×	(Optional) Screw Terminal Expansion Board for Raspberry Pi Pico

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.
Additionally, some of these links are for products from our own brand, DIYables.

Overview of Water/Liquid Valve

Pinout

A solenoid valve usually has two connections.

Attach the positive (+) pin (red) to the 12V DC power supply.
Attach the negative (-) pin (black or other) to the GND of the DC power supply.

How Water/Liquid Valve works

Normally, the valve is closed. When you connect 12V DC to the two points, the valve opens and lets water or other fluids flow through.

※ NOTE THAT:

Some valves contain a gasket and require a certain pressure to open when 12V DC is applied. This pressure comes from the liquid flow. Also, some valves let liquid pass through only one way.

How to Control Water/Liquid Solenoid Valve

When the valve gets 12V power, it opens. You need a relay to control the valve using the Raspberry Pi Pico. The Raspberry Pi Pico uses the relay to control the valve. If you don't know how a relay works, its pin setup, or how to set it up, check out the Raspberry Pi Pico - Relay tutorial.

Wiring Diagram

This image is created using Fritzing. Click to enlarge image

Raspberry Pi Pico Code

This code will switch the water valve ON for five seconds, then switch it OFF for another five seconds.

""" This Raspberry Pi Pico MicroPython code was developed by newbiely.com This Raspberry Pi Pico code is made available for public use without any restriction For comprehensive instructions and wiring diagrams, please visit: https://newbiely.com/tutorials/raspberry-pico/raspberry-pi-pico-water-liquid-valve """ from machine import Pin import time RELAY_PIN = 1 # The Raspberry Pi Pico pin GP1 connected to the water valve via relay pin # Initialize the relay pin as an output relay = Pin(RELAY_PIN, Pin.OUT) # Infinite loop while True: relay.value(1) # Turn on water valve for 5 seconds time.sleep(5) relay.value(0) # Turn off water valvefor 5 seconds time.sleep(5)

Detailed Instructions

Please follow these instructions step by step:

Ensure that Thonny IDE is installed on your computer.
Ensure that MicroPython firmware is installed on your Raspberry Pi Pico.
If this is your first time using a Raspberry Pico, refer to the Raspberry Pi Pico - Getting Started tutorial for detailed instructions.
Wire the Raspberry Pi Pico to the water valve according to the provided diagram.
Connect the Raspberry Pi Pico to your computer using a USB cable.
Launch the Thonny IDE on your computer.
On Thonny IDE, select MicroPython (Raspberry Pi Pico) Interpreter by navigating to Tools Options.
In the Interpreter tab, select MicroPython (Raspberry Pi Pico) from the drop-down menu.
Ensure the correct port is selected. Thonny IDE should automatically detect the port, but you may need to select it manually (e.g., COM3 on Windows or /dev/ttyACM0 on Linux).
Copy the above code and paste it to the Thonny IDE's editor.
Save the script to your Raspberry Pi Pico by:

Click the Save button, or use Ctrl+S keys.
In the save dialog, you will see two sections: This computer and Raspberry Pi Pico. Select Raspberry Pi Pico
Save the file as main.py

Click the green Run button (or press F5) to run the script. The script will execute.
Check the water flow.

If you name your script main.py and save it to the root directory of the Raspberry Pi Pico, it will automatically run each time the Pico is powered on or reset. This is useful for standalone applications that need to start running immediately upon power-up. If you name your script another name other than main.py, you will need to manually run it from Thonnys's Shell.

Code Explanation

You can find the explanation in the comments of the Raspberry Pi Pico code provided.

Video Tutorial

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