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CMakeLists.txt
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README.md

SinricPro Fan Example

Control a DC fan with voice commands - variable speed control with PWM.

Hardware

  • ESP32 board
  • DC fan (5V or 12V)
  • MOSFET or motor driver (e.g., L293D, L298N, IRF520)
  • External power supply matching fan voltage
  • Flyback diode (1N4007 or similar)

Wiring

Using MOSFET (IRF520)

ESP32 GPIO25      → MOSFET Gate
MOSFET Source     → GND (common ground with ESP32)
MOSFET Drain      → Fan Negative (-)
Fan Positive (+)  → External Power Supply (+)
Power Supply (-)  → GND (common ground)
Flyback Diode     → Across fan terminals (cathode to +)

Using L298N Motor Driver

ESP32 GPIO25 → IN1 (PWM input)
ESP32 GND    → GND
OUT1/OUT2    → Fan
12V/5V       → External power supply

Features

  • Variable speed control 0-100%
  • PWM-based motor control (25kHz)
  • Speed adjustment (increase/decrease)
  • Physical button for preset cycling
  • Smooth speed transitions

Voice Commands

  • "Alexa, turn on the fan"
  • "Alexa, turn off the fan"
  • "Alexa, set fan speed to 75"
  • "Alexa, set fan to maximum"
  • "Alexa, increase fan speed"
  • "Alexa, decrease fan speed"

Build

cd examples/fan
idf.py build flash monitor

Configuration

Edit main/fan_example.c - update WiFi and SinricPro credentials.

For different GPIO or PWM settings, modify:

#define FAN_GPIO                (25)
#define FAN_FREQUENCY           (25000)  /* 25 kHz */
#define BUTTON_GPIO             (0)

Speed Presets

Press BOOT button to cycle through:

  • OFF (0%)
  • LOW (33%)
  • MEDIUM (66%)
  • HIGH (100%)

Hardware Notes

  1. MOSFET Selection: Use logic-level MOSFETs (IRF520, IRLZ44N) for 3.3V GPIO
  2. Flyback Diode: REQUIRED to protect against inductive kickback
  3. Common Ground: ESP32 and fan power supply must share common ground
  4. PWM Frequency: 25kHz is above audible range (prevents buzzing)
  5. Minimum Speed: Code sets minimum 20% duty for fan startup

Safety

  • Never power high-current devices directly from ESP32 pins
  • Always use appropriate motor driver or MOSFET
  • Add flyback diode for inductive loads
  • Use proper heat sinking for high-power applications