How to Use 2 Channel 5V Relay Module ESP 32: Examples, Pinouts, and Specs

The 2 Channel 5V Relay Module ESP32, manufactured by Espressif, is a versatile electronic component designed for controlling high-power devices such as lights, fans, and appliances. It integrates seamlessly with the ESP32 microcontroller, enabling wireless control via Wi-Fi or Bluetooth. This module is ideal for home automation, IoT projects, and industrial control systems.

Common applications include:

• Smart home automation (e.g., controlling lights or appliances remotely)
• Industrial equipment control
• IoT-based switching systems
• Prototyping and educational projects

The following are the key technical details of the 2 Channel 5V Relay Module ESP32:

• Operating Voltage: 5V DC
• Relay Channels: 2
• Control Signal Voltage: 3.3V (compatible with ESP32 GPIO pins)
• Maximum Load (per channel):
  • AC: 250V at 10A
  • DC: 30V at 10A
• Trigger Mode: Active low
• Isolation: Optocoupler isolation for safe operation
• Dimensions: 50mm x 40mm x 18mm (approx.)

The module has two main interfaces: the input control pins and the relay output terminals.

1. Power the Module: Connect the VCC pin of the relay module to the 5V pin of the ESP32 and the GND pin to the ESP32's GND.
2. Control Pins: Connect the IN1 and IN2 pins to two GPIO pins on the ESP32 (e.g., GPIO 26 and GPIO 27).
3. Relay Outputs: Wire the devices you want to control to the relay output terminals (COM, NO, NC) as per your requirements.

• Relay 1: Connect a light bulb to the NO terminal of Relay 1, and the other end to the power source. Connect the COM terminal to the neutral line.
• Relay 2: Similarly, connect another device to Relay 2's terminals.

Below is an example Arduino sketch to control the relay module using an ESP32:

// Define GPIO pins for the relay control signals
#define RELAY1_PIN 26  // GPIO pin connected to IN1
#define RELAY2_PIN 27  // GPIO pin connected to IN2

void setup() {
  // Initialize serial communication for debugging
  Serial.begin(115200);

  // Set relay pins as outputs
  pinMode(RELAY1_PIN, OUTPUT);
  pinMode(RELAY2_PIN, OUTPUT);

  // Ensure relays are off at startup
  digitalWrite(RELAY1_PIN, HIGH); // Active low, so HIGH turns it off
  digitalWrite(RELAY2_PIN, HIGH); // Active low, so HIGH turns it off
}

void loop() {
  // Turn on Relay 1
  Serial.println("Turning on Relay 1...");
  digitalWrite(RELAY1_PIN, LOW); // Active low, so LOW turns it on
  delay(2000); // Wait for 2 seconds

  // Turn off Relay 1 and turn on Relay 2
  Serial.println("Turning off Relay 1 and turning on Relay 2...");
  digitalWrite(RELAY1_PIN, HIGH); // Turn off Relay 1
  digitalWrite(RELAY2_PIN, LOW);  // Turn on Relay 2
  delay(2000); // Wait for 2 seconds

  // Turn off both relays
  Serial.println("Turning off both relays...");
  digitalWrite(RELAY1_PIN, HIGH);
  digitalWrite(RELAY2_PIN, HIGH);
  delay(2000); // Wait for 2 seconds
}

• Power Supply: Ensure the module is powered with a stable 5V DC supply. Using an unstable power source may cause erratic behavior.
• Isolation: The module uses optocouplers for isolation, but additional precautions should be taken when working with high voltages.
• GPIO Voltage Compatibility: The module is designed to work with 3.3V control signals, making it fully compatible with the ESP32.

1. Relays not switching:

   • Ensure the VCC and GND connections are secure.
   • Verify that the control signals (IN1, IN2) are being correctly toggled by the ESP32.
   • Check if the power supply is providing sufficient current.

2. Relay clicks but no output:

   • Double-check the wiring of the relay output terminals (COM, NO, NC).
   • Ensure the load connected to the relay is within the specified voltage and current ratings.

3. ESP32 resets when relay is activated:

   • This may occur due to insufficient power supply. Use a separate 5V power source for the relay module.

Q: Can I use this module with a 12V power supply?
A: No, this module is designed to operate at 5V DC. Using a higher voltage may damage the module.

Q: Is it safe to control AC appliances with this module?
A: Yes, but ensure proper insulation and follow safety guidelines when working with high voltages.

Q: Can I control the relays via Wi-Fi or Bluetooth?
A: Yes, the ESP32 can be programmed to receive commands over Wi-Fi or Bluetooth and control the relays accordingly.

Q: What is the maximum switching frequency of the relays?
A: Mechanical relays are not designed for high-frequency switching. For most applications, a switching frequency of 1Hz or lower is recommended.

By following this documentation, you can effectively integrate and use the 2 Channel 5V Relay Module ESP32 in your projects.