esp-hal-servo

A library for controlling servo motors using ESP32 LEDC (LED Control) peripheral. No esp-idf and std dependencies (pure esp-hal).

Features

• Control servo motors using PWM via LEDC
• Support for custom servo configurations (SG90/SG90S preconfigured)
• Angle calculation and position tracking
• Support for all ESP32 variants (ESP32, ESP32C2, ESP32C3, ESP32C6, ESP32H2, ESP32S2, ESP32S3)
• Optional async support via embedded-hal-async (enable async feature)

Chip Features

This library supports all ESP32 variants through optional features. You must enable at least one chip feature:

• esp32 - Original ESP32
• esp32c2 - ESP32-C2
• esp32c3 - ESP32-C3
• esp32c6 - ESP32-C6
• esp32h2 - ESP32-H2
• esp32s2 - ESP32-S2
• esp32s3 - ESP32-S3

Usage

Add the library to your Cargo.toml with the appropriate chip feature:

[dependencies]
esp-hal-servo = { version = "0.4", features = ["esp32c3"] }

To enable async support, add the async feature:

[dependencies]
esp-hal-servo = { version = "0.4", features = ["esp32c3", "async"] }
embedded-hal-async = "1.0"

Note: You'll also need to provide an implementation of embedded-hal-async::delay::DelayNs trait. For example, with Embassy runtime, you can use embassy-time (which implements DelayNs).

API Overview

This library provides two approaches for controlling servo motors:

1. Direct Angle Control

Simply specify the desired angle and the servo will move to that position:

// Set servo to a specific angle (e.g., 42 degrees)
servo.set_angle(42.0);

2. Step-by-Step Control with Direction

Control the servo incrementally by setting direction and making steps:

// Set direction to clockwise
servo.set_dir(Dir::CW);
// Make a step of 10 duty units
servo.step(10.0)?;
// Or make a step as a percentage of the total range
servo.step_pct(5)?; // 5% of the range

Use direct angle control when you need to position the servo at a specific angle.
Use step-by-step control when you need smooth, incremental movement or continuous rotation.

3. Async Control (Optional)

Enable async feature for using AsyncServo (allows non-blocking servo control). Delay is automatically calculated based on servo speed and rotation angle.

The AsyncServo wrapper accepts any implementation of embedded-hal-async::delay::DelayNs trait, making it compatible with any async runtime (Embassy, RTOS, etc.).

use esp_hal_servo::{Servo, ServoConfig, async_servo::AsyncServo};
use embedded_hal_async::delay::DelayNs;

// Create servo with speed of 60 degrees per second (typical for SG90)
// Speed is configured in ServoConfig (e.g., ServoConfig::sg90() sets it to 60.0)
// delay must implement DelayNs trait (e.g., embassy-time::Delay)
let servo = Servo::new("servo", config, &mut ledc, &mut timer, channel_num, pin)?;
let mut async_servo = AsyncServo::new(servo, delay);

// Set angle asynchronously (delay is automatically calculated)
async_servo.set_angle(90.0).await;

// Step asynchronously (delay is automatically calculated)
async_servo.set_dir(Dir::CW);
async_servo.step_async(10.0).await?;

Examples

examples/README.md for more information about available examples.