Published April 23, 2025

Relay Module 2 Channel

2-Channel Relay Module lets you control 2 high-voltage devices using microcontrollers like Arduino or Raspberry Pi with signal pins.

IntermediateProtip4 hours102

Things used in this project

Hardware components

1N4007 – High Voltage, High Current Rated Diode

5 mm LED: Red

Bipolar (BJT) Single Transistor, 1 A

Relay (generic)

Tube Liquid Sensor, Phototransistor

Wire-To-Board Terminal Block, 3 Positions

Resistor 1k ohm

Through Hole Resistor, 510 ohm

Software apps and online services

CircuitMaker by Altium Circuit Maker

Hand tools and fabrication machines

You3Dit Industrial Design & Fabricated Prototype

Story

What is My project about?

My project is about using a 2-Channel Relay Module to control electrical devices like lights or fans through a Raspberry Pi. The relay acts like a switch that turns devices on or off based on the Pi's signal.

Why did I decide to make it?

I wanted to learn how to control real-world electrical devices using digital signals. This project helped me understand how automation and smart systems work using simple electronics.

How does it work?

The relay module receives a signal from the Raspberry Pi on pins IN1 and IN2.

The relay module receives a signal from the Raspberry Pi on pins IN1 and IN2.

When the signal is LOW (or HIGH depending on the module), the relay activates and connects the circuit.

When the signal is LOW (or HIGH depending on the module), the relay activates and connects the circuit.

This allows current to flow to the device (e.g., a light), turning it on.

This allows current to flow to the device (e.g., a light), turning it on.

When the signal is reversed, the relay disconnects the circuit and turns off the device.

When the signal is reversed, the relay disconnects the circuit and turns off the device.

Relay_Module Schematic

Relay_Module PCB

Schematics

Code

Relay_Module code

import RPi.GPIO as GPIO
import time

relay1_pin = 17 
relay2_pin = 27 

GPIO.setmode(GPIO.BCM)
GPIO.setup(relay1_pin, GPIO.OUT)
GPIO.setup(relay2_pin, GPIO.OUT)

GPIO.output(relay1_pin, GPIO.HIGH)
GPIO.output(relay2_pin, GPIO.HIGH)

try:
    while True:
        print("Turning Relay 1 ON")
        GPIO.output(relay1_pin, GPIO.LOW)  # Active LOW
        time.sleep(2)

        print("Turning Relay 2 ON")
        GPIO.output(relay2_pin, GPIO.LOW)
        time.sleep(2)

        print("Turning both OFF")
        GPIO.output(relay1_pin, GPIO.HIGH)
        GPIO.output(relay2_pin, GPIO.HIGH)
        time.sleep(2)

except KeyboardInterrupt:
    print("Program stopped by user")

finally:
    GPIO.cleanup()

Credits

Eman Tarek

3 projects • 0 followers

Electronics engineering student. I design complex hardware-only circuits using logic ICs, sensors, and analog components. No coding.

Contact

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Relay Module 2 Channel

Relay Module 2 Channel

Things used in this project

Hardware components

Software apps and online services

Hand tools and fabrication machines

Story

What is My project about?

Why did I decide to make it?

How does it work?

Custom parts and enclosures

Relay_Module PCB

Schematics

Relay_Module Schematic

Code

Relay_Module code

Credits

Eman Tarek

Comments

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