How to Use Relay 4 Channel 5v: Examples, Pinouts, and Specs

The Relay 4 Channel 5V module is an electronic component designed to control high-voltage devices using low-voltage signals. It features four independent relays, each capable of switching AC or DC loads. This module is widely used in home automation, industrial control systems, and IoT projects. Its ability to interface with microcontrollers like Arduino, Raspberry Pi, and other logic-level devices makes it a versatile choice for controlling lights, motors, fans, and other appliances.

• Home automation systems (e.g., controlling lights, fans, or appliances)
• Industrial equipment control
• IoT projects for remote device management
• Robotics and motor control
• Security systems (e.g., activating alarms or locks)

• Operating Voltage: 5V DC
• Trigger Voltage: 3.3V to 5V (logic-level compatible)
• Relay Channels: 4 (independent)
• Relay Type: SPDT (Single Pole Double Throw)
• Maximum Load (per relay):
  • AC: 250V at 10A
  • DC: 30V at 10A
• Isolation: Optocoupler isolation for each channel
• Indicator LEDs: One LED per relay to indicate activation
• Dimensions: Approximately 75mm x 55mm x 20mm

The Relay 4 Channel 5V module has two main interfaces: the input control pins and the relay output terminals.

Each relay has three output terminals:

1. Power the Module: Connect the VCC pin to a 5V DC power source and the GND pin to ground.
2. Connect Control Signals: Use digital output pins from a microcontroller (e.g., Arduino) to control the IN1, IN2, IN3, and IN4 pins. A LOW signal activates 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, depending on whether you want the device to be normally off or on.
4. Activate the Relays: Send LOW signals to the input pins to activate the relays and control the connected devices.

• Isolation: Ensure proper electrical isolation between the high-voltage side (relay outputs) and the low-voltage control side to avoid damage to your microcontroller.
• Power Supply: Use a stable 5V power supply to avoid erratic relay behavior.
• Inductive Loads: When controlling inductive loads (e.g., motors), use a flyback diode across the load to protect the relay from voltage spikes.
• Active LOW Logic: Remember that the relays are activated by a LOW signal on the input pins.

Below is an example of how to control the Relay 4 Channel 5V module using an Arduino UNO.

• Connect the module's VCC to the Arduino's 5V pin.
• Connect the module's GND to the Arduino's GND pin.
• Connect IN1, IN2, IN3, and IN4 to Arduino digital pins 7, 6, 5, and 4, respectively.
• Connect a load (e.g., a light bulb) to the COM and NO terminals of one relay.

// Define relay control pins
#define RELAY1 7  // Pin connected to IN1
#define RELAY2 6  // Pin connected to IN2
#define RELAY3 5  // Pin connected to IN3
#define RELAY4 4  // 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);  // Turn ON Relay 1
  delay(1000);                // Wait 1 second
  digitalWrite(RELAY1, HIGH); // Turn OFF Relay 1
  delay(1000);                // Wait 1 second

  digitalWrite(RELAY2, LOW);  // Turn ON Relay 2
  delay(1000);                // Wait 1 second
  digitalWrite(RELAY2, HIGH); // Turn OFF Relay 2
  delay(1000);                // Wait 1 second

  // Repeat for other relays as needed
}

1. Relays Not Activating:

   • Cause: Insufficient power supply.
   • Solution: Ensure the module is powered with a stable 5V DC source.

2. Erratic Relay Behavior:

   • Cause: Electrical noise or unstable control signals.
   • Solution: Use decoupling capacitors near the power supply and ensure proper grounding.

3. Microcontroller Resetting:

   • Cause: High current draw from the relays.
   • Solution: Use an external power supply for the relay module instead of powering it directly from the microcontroller.

4. Load Not Switching:

   • Cause: Incorrect wiring of the load to the relay terminals.
   • Solution: Double-check the connections to the COM, NO, and NC terminals.

Q: Can I use this module with a 3.3V microcontroller?
A: Yes, the module is compatible with 3.3V logic levels, but ensure the VCC pin is still powered with 5V.

Q: Can I control DC motors with this module?
A: Yes, but for inductive loads like motors, use a flyback diode to protect the relay from voltage spikes.

Q: What is the maximum current the relays can handle?
A: Each relay can handle up to 10A at 250V AC or 30V DC. Ensure your load does not exceed these ratings.