#encoder #rotary #embedded-hal #rotary-encoder

no-std rotary-encoder-embedded

A rotary-encoder library built with embedded-hal

7 releases

0.2.0 Oct 6, 2022
0.1.1 Jul 1, 2022
0.1.0 Feb 27, 2022
0.0.4 May 19, 2021
0.0.2 Feb 28, 2021

#476 in Embedded development

23 downloads per month

MIT license

13KB
184 lines

rotary-encoder-embedded

A rotary encoder library for embedded rust applications

rotary encoder

features

modes

The RotaryEncoder can operate in a number of different modes, these modes provide different types of feature sets and are individually gated behind feature flags to keep the binary size to a minimum. The following modes are currently provided:

Feature flag Mode Desc.
standard StandardMode Uses a state machine for transitions
angular-velocity AngularVelocityMode Same as standard but with additional angular-velocity calculations

StandardMode example

fn main() -> ! {
    // Configure DT and CLK pins, typically pullup input
    let rotary_dt = gpio_pin_1.into_pull_up_input()
    let rotary_clk = gpio_pin_2.into_pull_up_input();
    // Initialize the rotary encoder
    let mut rotary_encoder = RotaryEncoder::new(
        rotary_dt,
        rotary_clk,
    ).into_standard_mode();
    // ...timer initialize at 900Hz to poll the rotary encoder
    loop {}
}

fn timer_interrupt_handler() {
    // ... get rotary encoder 
    let rotary_encoder = ...
    // Update the encoder, which will compute its direction
    rotary_encoder.update();
    match rotary_encoder.direction() {
        Direction::Clockwise => {
            // Increment some value
        }
        Direction::AntiClockwise => {
            // Decrement some value
        }
        Direction::None => {
            // Do nothing
        }
    }
}

A note about GPIO or Timer interrupt usage

I've experimented a lot with different combinations in order to make Rotary Encoders behave predictably because generally speaking they are fickle at best. From my experimentation I've learnt that using GPIO pin based interrupts generally isn't a good idea because they are more prone to noise and increase the risk of misfires and jumps. Timers on the other hand provide a low pass filtering quality because they don't pick up higher frequency switching that GPIO interrupts do. I have found that using a Timer between 850-1000Hz seems to work best.

Dependencies

~71KB