This project demonstrates how to interface a two-channel relay module with an Arduino to control two LEDs. The LEDs will be toggled on and off to show the relay functions.

• Arduino (e.g., Uno, Nano)
• Two-channel Relay Module
• Jumper Wires
• Two LEDs (Red and Green)
• Breadboard
• Resistors (220 ohms recommended)

• VCC of the relay module to 5V on the Arduino
• GND of the relay module to GND on the Arduino
• IN1 of the relay module to digital pin 7 on the Arduino
• IN2 of the relay module to digital pin 8 on the Arduino

• Relay 1 (IN1)

  • COM terminal to the cathode (short leg) of the Red LED
  • NO terminal to GND
  • Anode (long leg) of the Red LED to a current limiting resistor (220 ohms recommended)
  • Resistor to 5V

• Relay 2 (IN2)

  • COM terminal to the cathode (short leg) of the Green LED
  • NO terminal to GND
  • Anode (long leg) of the Green LED to a current limiting resistor (220 ohms recommended)
  • Resistor to 5V

1. Initialization: The relay pins are set as outputs in the setup function and start in the LOW state (off).
2. Loop Function: The loop function toggles the relays:
   • Turns the first relay on and the second relay off, then waits for one second.
   • Turns the first relay off and the second relay on, then waits for one second.
3. LED Indication: The LEDs connected to the relay's NO and COM terminals will show the relay state. When the relay is activated, the LED will light up.

• Low Voltage: This example uses low voltage (5V) LEDs. If using higher voltage devices, ensure proper insulation and safety measures.
• Circuit Disconnection: Always disconnect the power while setting up the circuit to avoid any electrical hazards.

This code is designed by Prince Kushwaha from COSM Electronics.