How to Use 5V One channel relay with OPTO lsolation H/L level triggerrigger: Examples, Pinouts, and Specs

The 5V One Channel Relay with OPTO Isolation is a versatile and reliable module designed for controlling high-voltage devices using low-voltage signals. It features optical isolation, which enhances safety by electrically isolating the control circuit from the high-voltage load. This relay module can be triggered by either a high-level or low-level signal, making it compatible with a wide range of microcontrollers and control systems.

• Home automation systems (e.g., controlling lights, fans, or appliances)
• Industrial control systems
• Robotics and IoT projects
• Switching high-power devices such as motors, solenoids, or heaters
• Safety-critical applications requiring electrical isolation

• Operating Voltage: 5V DC
• Trigger Voltage: High-level (2.5V–5V) or Low-level (0V–1.5V)
• Relay Type: SPDT (Single Pole Double Throw)
• Maximum Load:
  • AC: 250V at 10A
  • DC: 30V at 10A
• Optical Isolation: Yes
• Indicator LED: Yes (indicates relay activation)
• Dimensions: ~50mm x 26mm x 18.5mm
• Weight: ~15g

The module has a total of 6 pins and 3 terminal blocks. Below is the detailed pinout:

1. Power the Module:
   • Connect the VCC pin to a 5V DC power supply and the GND pin to ground.
2. Set the Trigger Mode:
   • Use the jumper to select the desired trigger mode:
     • H (High-level): The relay activates when the IN pin receives a HIGH signal.
     • L (Low-level): The relay activates when the IN pin receives a LOW signal.
3. Connect the Load:
   • Connect the high-voltage device to the relay's terminal block:
     • Use the COM terminal as the common connection.
     • Use the NO terminal if the device should activate when the relay is triggered.
     • Use the NC terminal if the device should deactivate when the relay is triggered.
4. Control the Relay:
   • Send a control signal to the IN pin from a microcontroller or other control circuit.

• Optical Isolation: Ensure the control circuit and high-voltage circuit are properly isolated to prevent damage or hazards.
• Power Supply: Use a stable 5V DC power supply to avoid erratic relay behavior.
• Load Ratings: Do not exceed the relay's maximum load ratings (250V AC/10A or 30V DC/10A).
• Signal Compatibility: Ensure the control signal voltage matches the selected trigger mode (H or L).
• Indicator LED: Use the onboard LED as a visual indicator of relay activation.

Below is an example of how to connect and control the relay module using an Arduino UNO:

• Relay Module:
  • VCC → 5V pin on Arduino
  • GND → GND pin on Arduino
  • IN → Digital pin 7 on Arduino
• Load:
  • Connect the high-voltage device to the COM and NO terminals.

// Define the relay control pin
const int relayPin = 7;

void setup() {
  // Set the relay pin as an output
  pinMode(relayPin, OUTPUT);
  
  // Ensure the relay is off at startup
  digitalWrite(relayPin, LOW);
}

void loop() {
  // Turn the relay on
  digitalWrite(relayPin, HIGH);
  delay(1000); // Keep the relay on for 1 second
  
  // Turn the relay off
  digitalWrite(relayPin, LOW);
  delay(1000); // Keep the relay off for 1 second
}

• Modify the relayPin variable if using a different digital pin.
• Ensure the Arduino's 5V pin can supply sufficient current for the relay module.

1. Relay Not Activating:

   • Cause: Insufficient power supply or incorrect wiring.
   • Solution: Verify the VCC and GND connections and ensure a stable 5V DC supply.

2. Erratic Behavior:

   • Cause: Electrical noise or unstable control signals.
   • Solution: Use a decoupling capacitor (e.g., 100µF) across the VCC and GND pins.

3. Load Not Switching:

   • Cause: Incorrect terminal connections.
   • Solution: Double-check the connections to the COM, NO, and NC terminals.

4. Indicator LED Not Lighting:

   • Cause: Faulty module or incorrect trigger signal.
   • Solution: Test the IN pin with a direct HIGH or LOW signal to confirm functionality.

• Q: Can I use this relay module with a 3.3V microcontroller?
  A: Yes, but ensure the trigger voltage matches the selected mode (H or L). For 3.3V systems, use the low-level trigger mode.

• Q: Is it safe to control high-power devices with this module?
  A: Yes, as long as the load does not exceed the relay's maximum ratings and proper isolation is maintained.

• Q: Can I use this module to control DC motors?
  A: Yes, but consider adding a flyback diode across the motor terminals to protect the relay from voltage spikes.

• Q: What happens if I exceed the relay's load ratings?
  A: Exceeding the load ratings can damage the relay and pose safety risks. Always stay within the specified limits.

This documentation provides a comprehensive guide to using the 5V One Channel Relay with OPTO Isolation effectively and safely.