How to Use 1 Channel Relay module with Optocoupler: Examples, Pinouts, and Specs

The 1 Channel Relay Module with Optocoupler, manufactured by Songle (Part ID: SRD-05VDC-SL-C), is a versatile electronic component that allows microcontrollers to control high-power devices. This module uses an optocoupler to provide electrical isolation between the control circuit and the high-power load, ensuring safety and reliability.

• Home Automation: Control lights, fans, and other household appliances.
• Industrial Automation: Manage motors, solenoids, and other industrial equipment.
• Robotics: Operate actuators and other high-power components.
• IoT Projects: Integrate with smart home systems for remote control.

1. Power the Module:

   • Connect the VCC pin to a 5V DC power supply.
   • Connect the GND pin to the ground of the power supply.

2. Control Signal:

   • Connect the IN pin to a digital output pin of the microcontroller (e.g., Arduino UNO).

3. Load Connection:

   • Connect the high-power device to the NO (Normally Open) or NC (Normally Closed) and COM (Common) pins based on your requirement.

• Electrical Isolation: Ensure that the control circuit and the high-power load are electrically isolated to prevent damage to the microcontroller.
• Current Rating: Do not exceed the relay's contact rating of 10A to avoid damage.
• Flyback Diode: Use a flyback diode across inductive loads (e.g., motors) to protect the relay from voltage spikes.

/*
 * Example code to control a 1 Channel Relay Module with Optocoupler
 * using an Arduino UNO. The relay is connected to digital pin 7.
 */

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

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

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

1. Relay Not Switching:

   • Solution: Ensure the control signal voltage is within the specified range (0-5V). Check the connections and power supply.

2. High-Power Device Not Operating:

   • Solution: Verify the load connections (NO/NC and COM). Ensure the load does not exceed the relay's contact rating.

3. Microcontroller Resetting:

   • Solution: Ensure proper electrical isolation. Use a separate power supply for the relay module if necessary.

• Check Connections: Double-check all connections to ensure they are secure and correct.
• Use Proper Power Supply: Ensure the power supply provides sufficient current for the relay module and the load.
• Debounce Control Signal: If the relay is switching erratically, consider debouncing the control signal in the microcontroller code.

By following this documentation, users can effectively integrate the 1 Channel Relay Module with Optocoupler into their projects, ensuring safe and reliable operation.