How to Use Relay 4 Channel 3.3v: Examples, Pinouts, and Specs

The Relay 4 Channel 3.3V module is a versatile electronic component designed to control up to four independent circuits using a low-voltage 3.3V signal. This makes it an ideal interface for microcontrollers, such as the Arduino or Raspberry Pi, to manage high-voltage devices like lights, motors, or appliances. Each relay on the module acts as an electrically operated switch, allowing you to safely control high-power devices without directly exposing your microcontroller to high voltages.

• Home automation systems (e.g., controlling lights, fans, or appliances)
• Industrial control systems
• Robotics and motor control
• IoT (Internet of Things) projects
• Prototyping and testing high-voltage circuits

Below are the key technical details of the Relay 4 Channel 3.3V module:

The module has two main sections: the input (control) pins and the output (relay) terminals.

Each relay has three terminals: COM (Common), NO (Normally Open), and NC (Normally Closed).

1. Power the Module: Connect the VCC pin to a 3.3V power source and the GND pin to ground.
2. Connect Control Signals: Use digital output pins from your microcontroller to connect to the IN1, IN2, IN3, and IN4 pins. A LOW signal (0V) will activate the corresponding relay.
3. Connect the Load: For each relay, connect the device you want to control to the COM and NO or NC terminals:
   • Use the NO terminal if you want the device to turn ON when the relay is activated.
   • Use the NC terminal if you want the device to turn OFF when the relay is activated.
4. Test the Circuit: Ensure all connections are secure and test the circuit by toggling the control signals.

• Isolation: The module uses optocouplers for isolation, but always ensure proper grounding to avoid electrical noise or interference.
• Power Supply: Ensure the power supply can provide sufficient current for the relays and connected devices.
• High Voltage Safety: When working with high-voltage circuits, take necessary precautions to avoid electric shock or damage to components.
• Active LOW Trigger: The relays are triggered by a LOW signal. Ensure your microcontroller logic accounts for this behavior.

Below is an example of how to control the Relay 4 Channel 3.3V module using an Arduino UNO:

// Define relay control pins
const int relay1 = 2; // Pin connected to IN1
const int relay2 = 3; // Pin connected to IN2
const int relay3 = 4; // Pin connected to IN3
const int relay4 = 5; // Pin connected to IN4

void setup() {
  // Set relay pins as outputs
  pinMode(relay1, OUTPUT);
  pinMode(relay2, OUTPUT);
  pinMode(relay3, OUTPUT);
  pinMode(relay4, OUTPUT);

  // Initialize all relays to OFF (HIGH state)
  digitalWrite(relay1, HIGH);
  digitalWrite(relay2, HIGH);
  digitalWrite(relay3, HIGH);
  digitalWrite(relay4, HIGH);
}

void loop() {
  // Example: Turn relays ON and OFF with a delay
  digitalWrite(relay1, LOW); // Activate Relay 1
  delay(1000);               // Wait 1 second
  digitalWrite(relay1, HIGH); // Deactivate Relay 1
  delay(1000);               // Wait 1 second

  digitalWrite(relay2, LOW); // Activate Relay 2
  delay(1000);               // Wait 1 second
  digitalWrite(relay2, HIGH); // Deactivate Relay 2
  delay(1000);               // Wait 1 second

  // Repeat for other relays as needed
}

1. Relays Not Activating:

   • Ensure the VCC and GND connections are secure.
   • Verify that the control signals are correctly set to LOW to activate the relays.
   • Check if the power supply provides sufficient current for the module.

2. Microcontroller Resetting:

   • High-current devices may cause voltage drops. Use a separate power supply for the relay module if needed.

3. Load Not Responding:

   • Double-check the wiring of the load to the relay terminals (COM, NO, NC).
   • Ensure the load voltage and current are within the relay's rated limits.

• Use a multimeter to verify voltage levels at the input and output terminals.
• Test each relay individually to isolate issues.
• If using an Arduino, confirm that the GPIO pins are configured as outputs and are functioning correctly.

By following this documentation, you can effectively integrate the Relay 4 Channel 3.3V module into your projects and troubleshoot common issues with ease.