How to Use Modulo Dimmer: Examples, Pinouts, and Specs

The Modulo Dimmer (RobotDyn AC Light Dimmer Module) is an electronic device designed to control the brightness of AC-powered lighting fixtures. By varying the voltage or current supplied to the load, it enables precise dimming of incandescent, halogen, and some dimmable LED lights. This module is widely used in home automation, theatrical lighting, and energy-saving applications.

• Home Automation: Adjust lighting levels for comfort and energy efficiency.
• Theatrical Lighting: Create dynamic lighting effects for stage performances.
• Industrial Use: Control AC loads such as fans or heaters.
• Smart Lighting Systems: Integrate with microcontrollers like Arduino for automated dimming.

• Manufacturer: RobotDyn
• Part ID: AC Light Dimmer Module
• Input Voltage: 110V-220V AC
• Output Load: 0-200W (for 110V AC) / 0-400W (for 220V AC)
• Control Voltage: 3.3V-5V (compatible with most microcontrollers)
• Zero-Cross Detection: Built-in for precise dimming control
• Isolation: Optocoupler for safe interfacing with low-voltage circuits
• Dimensions: 50mm x 25mm x 20mm

The Modulo Dimmer has a 4-pin interface for connecting to a microcontroller and AC load.

1. Connect the AC Input and Output:

   • Connect the AC-IN terminals to the mains power supply (110V-220V AC).
   • Connect the AC-OUT terminals to the load (e.g., a dimmable light bulb).

2. Connect to a Microcontroller:

   • Connect the VCC and GND pins to the 3.3V or 5V power supply of your microcontroller.
   • Connect the PWM pin to a PWM-capable pin on the microcontroller.
   • Optionally, connect the Z-C pin to a digital input pin for zero-cross detection.

3. Write Control Code:

   • Use the PWM signal to control the brightness of the connected load.
   • Synchronize the PWM signal with the zero-cross detection signal for smooth dimming.

• Safety First: Always handle the module with care when working with high-voltage AC power. Ensure proper insulation and avoid touching live components.
• Load Compatibility: Verify that the connected load is dimmable and within the module's power rating.
• Zero-Cross Synchronization: For smooth dimming, use the zero-cross detection signal to synchronize the PWM signal with the AC mains frequency.
• Heat Dissipation: Ensure adequate ventilation or heat sinking if the module operates near its maximum power rating.

Below is an example of how to use the Modulo Dimmer with an Arduino UNO to control the brightness of a light bulb.

/*
  Example Code for RobotDyn AC Light Dimmer Module
  This code demonstrates how to control the brightness of a light bulb
  using PWM and zero-cross detection with an Arduino UNO.
*/

#define ZC_PIN 2    // Pin connected to the Zero-Cross detection signal
#define PWM_PIN 3   // Pin connected to the PWM input of the dimmer module

volatile boolean zeroCross = false; // Flag for zero-cross detection
int dimValue = 128;                 // Brightness level (0-255)
int delayTime;                      // Delay time for dimming

void zeroCrossISR() {
  // Interrupt Service Routine for zero-cross detection
  zeroCross = true;
}

void setup() {
  pinMode(ZC_PIN, INPUT);           // Set Zero-Cross pin as input
  pinMode(PWM_PIN, OUTPUT);         // Set PWM pin as output
  attachInterrupt(digitalPinToInterrupt(ZC_PIN), zeroCrossISR, RISING);
}

void loop() {
  if (zeroCross) {
    zeroCross = false;              // Reset zero-cross flag
    delayTime = (128 - dimValue) * 75; // Calculate delay for dimming
    delayMicroseconds(delayTime);   // Wait for the calculated delay
    digitalWrite(PWM_PIN, HIGH);    // Turn on the dimmer
    delayMicroseconds(10);          // Keep it on for a short duration
    digitalWrite(PWM_PIN, LOW);     // Turn off the dimmer
  }
}

1. The light does not dim or flickers:

   • Ensure the load is dimmable (e.g., incandescent or dimmable LED).
   • Verify proper synchronization with the zero-cross signal.
   • Check the PWM signal from the microcontroller.

2. The module overheats:

   • Ensure the load does not exceed the module's power rating.
   • Provide adequate ventilation or heat sinking.

3. No response from the module:

   • Verify all connections, especially the AC input and output.
   • Check the microcontroller's PWM output and ensure it is connected to the correct pin.

4. Zero-cross detection not working:

   • Ensure the Z-C pin is properly connected to the microcontroller.
   • Check for noise or interference in the AC mains supply.

• Can I use this module with a 3.3V microcontroller?
  Yes, the module is compatible with both 3.3V and 5V logic levels.

• Is this module suitable for non-dimmable LEDs?
  No, non-dimmable LEDs may not work correctly and could be damaged.

• Can I control multiple dimmers with one microcontroller?
  Yes, but ensure each dimmer has its own zero-cross detection and PWM control pin.

• What happens if I exceed the power rating?
  Exceeding the power rating may damage the module or cause overheating. Always stay within the specified limits.

This concludes the documentation for the RobotDyn AC Light Dimmer Module.