Dimmer Types

MycilaDimmer provides four dimmer implementations, each suited to different hardware and use cases. All share the same unified API.

Thyristor Dimmer

Perfect for TRIAC and Random SSR control with flicker-free progressive dimming. Achieves smooth, continuous power control through precise phase angle control when paired with quality zero-cross detection circuits.

ESP32	Random Solid State Relay	Heat Sink	Zero-Cross Detection Module

#include <MycilaDimmers.h>

Mycila::ThyristorDimmer dimmer;

void setup() {
  dimmer.setPin(GPIO_NUM_26);
  Mycila::Dimmer::setSemiPeriod(10000); // 50Hz AC (10ms semi-period) - shared across all dimmers
  dimmer.begin();

  // Register with external zero-cross detector
  pulseAnalyzer.onZeroCross(Mycila::ThyristorDimmer::onZeroCross);
}

Features:

• Flicker-free dimming: Smooth progressive control without visible flickering
• Microsecond-precision phase angle control
• Lookup table with linear interpolation for seamless transitions
• IRAM-safe interrupt handlers
• Supports several zero-cross detection circuits:
• Zero-Cross Detector from Daniel S
• JSY-MK-194G
• RobotDyn ZCD
• BM1Z102FJ
• Any other ZCD circuit providing a clean digital pulse at each zero-crossing

Tip

The Zero-Cross Detector on DIN Rail mount from Daniel S is very good and reliable and sometimes available in bulk from PCBWay. See the YaSolR Pro page for stock status.

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Cycle Stealing Dimmer

Perfect for resistive loads (heaters, water tank heaters) with zero noise. Uses an advanced First-Order Delta-Sigma Modulator (Bresenham's algorithm) to distribute power evenly across AC cycles while strictly maintaining DC balance on the grid.

ESP32	Solid State Relay (Zero-Cross)	Heat Sink

#include <MycilaDimmers.h>

Mycila::CycleStealingDimmer dimmer;

void setup() {
  dimmer.setPin(GPIO_NUM_26);
  Mycila::Dimmer::setSemiPeriod(10000); // Required: 50Hz=10000, 60Hz=8333
  dimmer.begin();
  dimmer.setOnline(true);

  // If using a Random SSR (non zero-cross), provide ZCD signal:
  // pulseAnalyzer.onZeroCross(Mycila::CycleStealingDimmer::onZeroCross);
}

Features:

• Zero Noise: Switches only at zero-crossings, generating virtually no electrical noise
• DC Balance: Advanced algorithm ensures equal positive and negative half-cycles to prevent grid DC offset
• High Resolution: Delta-Sigma modulation provides precise power control at ~1% steps
• Resistive Loads: Ideal for water heaters, oil radiators, and other thermal loads
• Hardware: Works with standard Zero-Cross SSRs (cheaper) or Random SSRs with ZCD
• No Power LUT: CycleStealingDimmer does not support the Power LUT feature (it is only available on phase-control dimmers)

Info

See the Cycle Stealing Algorithm page for a detailed explanation of the Delta-Sigma modulator used.

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PWM Dimmer

Standard PWM output for PWM-to-analog converters to control voltage regulators.

ESP32	Voltage Regulator	Heat Sink	PWM to Analog Converter

#include <MycilaDimmers.h>

Mycila::PWMDimmer dimmer;

void setup() {
  dimmer.setPin(GPIO_NUM_26);
  dimmer.setFrequency(1000);  // 1kHz PWM
  dimmer.setResolution(12);   // 12-bit resolution
  Mycila::Dimmer::setSemiPeriod(10000); // Required when using Power LUT
  dimmer.enablePowerLUT(true);
  dimmer.begin();
  dimmer.setOnline(true);
}

Features:

• Configurable frequency (default: 1kHz)
• Configurable resolution (default: 12-bit)
• Automatic PWM channel management

For example, this dimmer can be used with a 3.3V to 0-5V/0-10V signal converter.

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DFRobot DAC Dimmer

Flicker-free progressive dimming using precision I2C DAC modules. Perfect for voltage regulator controlled devices (LSA, LCTC, etc) with 0-10V input, providing ultra-smooth dimming without any visible flickering thanks to high-resolution DAC output.

ESP32	Voltage Regulator	Heat Sink	DFRobot DAC

#include <MycilaDimmers.h>
#include <Wire.h>

Mycila::DFRobotDimmer dimmer;

void setup() {
  Wire.begin(SDA, SCL);
  dimmer.setWire(Wire);
  dimmer.setSKU(Mycila::DFRobotDimmer::SKU::DFR1071_GP8211S);
  dimmer.setDeviceAddress(0x59);
  dimmer.setOutput(Mycila::DFRobotDimmer::Output::RANGE_0_10V);
  Mycila::Dimmer::setSemiPeriod(10000); // Required when using Power LUT
  dimmer.enablePowerLUT(true);
  dimmer.begin();
  dimmer.setOnline(true);
}

Supported Models:

Model	Chip	Resolution	Channels	Voltage Range
DFR0971	GP8403	12-bit	Dual	0-5V / 0-10V
DFR1071	GP8211S	15-bit	Single	0-5V / 0-10V
DFR1073	GP8413	15-bit	Dual	0-5V / 0-10V

See the DFRobot comparison table for more details.