Note

Hello, welcome to the SunFounder Raspberry Pi & Arduino & ESP32 Enthusiasts Community on Facebook! Dive deeper into Raspberry Pi, Arduino, and ESP32 with fellow enthusiasts.

Why Join?

Expert Support: Solve post-sale issues and technical challenges with help from our community and team.
Learn & Share: Exchange tips and tutorials to enhance your skills.
Exclusive Previews: Get early access to new product announcements and sneak peeks.
Special Discounts: Enjoy exclusive discounts on our newest products.
Festive Promotions and Giveaways: Take part in giveaways and holiday promotions.

👉 Ready to explore and create with us? Click [here] and join today!

Lesson 30: Relay Module

In this lesson, you will learn how to use the Raspberry Pi Pico W to control a relay module. We will set up a basic circuit connecting the relay to the Pi and write a MicroPython script to toggle the relay on and off at one-second intervals. This project introduces you to controlling external devices such as relays and demonstrates practical output operations using the GPIO pins on the Raspberry Pi Pico W. Ideal for those interested in delving into home automation or managing other high-power devices, this lesson offers fundamental insight into how microcontrollers can interact with and control external hardware.

Required Components

In this project, we need the following components.

It’s definitely convenient to buy a whole kit, here’s the link:

Name	ITEMS IN THIS KIT	LINK
Universal Maker Sensor Kit	94	Universal Maker Sensor Kit

You can also buy them separately from the links below.

Component Introduction	Purchase Link
Raspberry Pi Pico W	BUY
5V Relay Module	-
RGB LED Module	-
Breadboard	BUY

Wiring

../_images/Lesson_30_Relay_Module_pico_bb.png

Code

from machine import Pin
import time

# Replace this number with the GPIO pin number your relay is connected to
relay_pin = Pin(16, Pin.OUT)

def relay_on():
    relay_pin.value(1)  # Set relay to ON state

def relay_off():
    relay_pin.value(0)  # Set relay to OFF state

try:
    while True:
        relay_on()
        print("on....")
        time.sleep(1)  # Wait for 1 second
        relay_off()
        print("off....")
        time.sleep(1)  # Wait for 1 second
except:
    relay_off()  # Ensure the relay is turned off in case of an exception
    print("Program interrupted, relay turned off.")

Code Analysis

Importing Libraries

The machine and time libraries are imported to interact with GPIO pins and handle time-related functions, respectively.
```
from machine import Pin
import time
```
Initializing Relay Pin

A GPIO pin is set up as an output pin to control the relay. The relay_pin variable represents the GPIO pin connected to the relay.
```
relay_pin = Pin(16, Pin.OUT)
```
Defining Relay Control Functions

Two functions, relay_on and relay_off, are defined to turn the relay on and off, respectively. These functions change the GPIO pin’s value to high (1) or low (0).
```
def relay_on():
    relay_pin.value(1)  # Set relay to ON state

def relay_off():
    relay_pin.value(0)  # Set relay to OFF state
```

Main Loop and Exception Handling

A continuous loop is created using while True. Inside this loop, the relay is turned on and off with a 1-second delay between each state. If an interruption occurs (like a keyboard interruption), the relay is turned off for safety, and a message is printed.

try:
    while True:
        relay_on()
        print("on....")
        time.sleep(1)  # Wait for 1 second
        relay_off()
        print("off....")
        time.sleep(1)  # Wait for 1 second
except:
    relay_off()  # Ensure the relay is turned off in case of an exception
    print("Program interrupted, relay turned off.")