How to Use 8-Channel AC 220V Optocoupler Input Module: Examples, Pinouts, and Specs

The 8-Channel AC 220V Optocoupler Input Module by Hailege is designed to safely interface high-voltage AC signals (up to 220V) with low-voltage control systems such as microcontrollers. This module uses optocouplers to provide electrical isolation, ensuring that high-voltage circuits do not directly interact with sensitive low-voltage components. It is ideal for applications requiring signal monitoring, industrial automation, and AC signal detection.

• Industrial automation systems
• AC signal monitoring and detection
• Electrical safety isolation in control systems
• Home automation projects
• Interfacing high-voltage AC devices with microcontrollers (e.g., Arduino, Raspberry Pi)

The following table outlines the key technical details of the module:

The module has two main interfaces: the AC input terminals and the low-voltage output pins. Below is the pin configuration:

1. Power the Module: Connect the VCC and GND pins to a 3.3V or 5V power source, depending on your microcontroller's logic level.
2. Connect AC Signals: Attach the AC signals (up to 220V) to the input terminals (IN1 to IN8). Ensure proper wiring and insulation to avoid electrical hazards.
3. Connect Outputs to Microcontroller: Connect the OUT1 to OUT8 pins to the digital input pins of your microcontroller. These pins will output a HIGH or LOW signal based on the presence of an AC signal on the corresponding input channel.
4. Verify Connections: Double-check all connections to ensure safety and proper operation.

• Safety First: Always handle the module with care when working with high-voltage AC signals. Ensure proper insulation and avoid touching live wires.
• Power Supply: Use a stable 3.3V or 5V power source for the module.
• Signal Frequency: The module is designed for standard AC frequencies (50Hz to 60Hz). It may not work correctly with non-standard frequencies.
• Output Logic: The output pins will typically output a LOW signal when an AC signal is detected and a HIGH signal when no AC signal is present. Verify this behavior with your specific module.

Below is an example of how to connect the module to an Arduino UNO and read the status of the AC inputs:

• Connect the module's VCC to the Arduino's 5V pin.
• Connect the module's GND to the Arduino's GND pin.
• Connect the module's OUT1 to Arduino digital pin 2, OUT2 to digital pin 3, and so on.

// Define the input pins for the module
const int inputPins[] = {2, 3, 4, 5, 6, 7, 8, 9}; // OUT1 to OUT8

void setup() {
  // Initialize serial communication for debugging
  Serial.begin(9600);

  // Set the input pins as INPUT
  for (int i = 0; i < 8; i++) {
    pinMode(inputPins[i], INPUT);
  }
}

void loop() {
  // Read and print the status of each channel
  for (int i = 0; i < 8; i++) {
    int status = digitalRead(inputPins[i]);
    Serial.print("Channel ");
    Serial.print(i + 1);
    Serial.print(": ");
    Serial.println(status == LOW ? "AC Signal Detected" : "No Signal");
  }

  // Add a small delay to avoid flooding the serial monitor
  delay(500);
}

1. No Output Signal Detected

   • Cause: Incorrect wiring or insufficient power supply.
   • Solution: Verify that the VCC and GND pins are properly connected and that the module is receiving the correct voltage.

2. Output Always HIGH or LOW

   • Cause: Faulty AC input connection or damaged optocoupler.
   • Solution: Check the AC input wiring and ensure the input voltage is within the specified range. Replace the module if necessary.

3. Microcontroller Not Detecting Output

   • Cause: Logic level mismatch or incorrect pin configuration.
   • Solution: Ensure the microcontroller's input pins are configured correctly and that the module's output logic level matches the microcontroller's requirements.

Q: Can this module handle DC signals?
A: No, this module is designed specifically for AC signals. It will not work correctly with DC inputs.

Q: Is the module compatible with 3.3V microcontrollers like ESP32?
A: Yes, the module's output is compatible with both 3.3V and 5V logic levels.

Q: Can I use fewer than 8 channels?
A: Yes, you can use as many channels as needed. Unused channels can be left unconnected.

Q: What happens if the input voltage exceeds 220V AC?
A: Exceeding the rated voltage may damage the module and pose a safety hazard. Always ensure the input voltage is within the specified range.