Servos

A hobby servo is a self-contained actuator with a DC motor, gearbox, and position-control electronics. It accepts a 50 Hz PWM signal and rotates its output shaft to the corresponding angle (typically 0–180°). Continuous-rotation servos use the same signal but spin indefinitely at variable speed.

PWM parameters

The ESP32Servo library wraps the ESP32's LEDC peripheral and provides the standard Arduino Servo API. Install via Library Manager → search ESP32Servo .

Basic position control

// Library Manager → search "ESP32Servo" by Kevin Harrington
#include <ESP32Servo.h>

Servo myServo;
const int SERVO_PIN = 23;

void setup() {
    myServo.attach(SERVO_PIN);
    myServo.write(90);       // start at center (90°)
}

void loop() {
    myServo.write(0);        // 0° — full left / closed
    delay(1000);
    myServo.write(90);       // 90° — center
    delay(1000);
    myServo.write(180);      // 180° — full right / open
    delay(1000);
}

Smooth sweep (gauge needle)

// Smooth sweep — cockpit gauge needle or flap indicator
#include <ESP32Servo.h>

Servo gauge;

void setup() {
    // attach(pin, minPulse_µs, maxPulse_µs)
    // Calibrate min/max for your specific servo model
    gauge.attach(23, 500, 2500);
}

void loop() {
    for (int pos = 0; pos <= 180; pos++) {
        gauge.write(pos);
        delay(8);            // ~8 ms per degree ≈ 1.44 s full sweep
    }
    for (int pos = 180; pos >= 0; pos--) {
        gauge.write(pos);
        delay(8);
    }
}

The ESP32's LEDC (LED Control) peripheral generates hardware PWM on any GPIO. This approach requires no extra library and gives precise control over frequency and resolution.

// Raw LEDC — no library (Arduino-ESP32 core 3.x API)
const int SERVO_PIN = 23;

// 50 Hz PWM, 16-bit resolution (65 535 ticks = 20 000 µs period)
// 1 000 µs = 0°   → duty ≈  3 277
// 2 000 µs = 180° → duty ≈  6 554

void setAngle(int angle) {
    int duty = map(angle, 0, 180, 3277, 6554);
    ledcWrite(SERVO_PIN, duty);
}

void setup() {
    ledcAttach(SERVO_PIN, 50, 16);
    setAngle(90);
}

void loop() {
    setAngle(0);
    delay(1000);
    setAngle(180);
    delay(1000);
}

Pulse-width limits vary by model. Adjust the map() bounds (3277 / 6554) if the servo does not reach its full range.