Crate dyn_smooth

dyn-smooth

This no_std Rust crate implements a dynamic smoothing filter based on an algorithm by Andrew Simper.

It uses a lowpass filter whose cutoff frequency is modulated dynamically by the signal itself and allows to track signal changes faster than a purely static version.

The main use of this crate is to smooth noisy or stepped signals like analog measurements from an ADC in embedded systems.

Status

Currently there are only implementations of the “efficient” variant using single-precision floats and 32-bit integers.

Usage Examples

Floating point

use dyn_smooth::DynamicSmootherEcoF32;

// Create an instance with suitable settings.
let base_freq = 2.0;
let sample_freq = 1000.0;
let sensitivity = 0.5;
let mut smoother = DynamicSmootherEcoF32::new(base_freq, sample_freq, sensitivity);

// Feed an input value to the smoother and retrieve the smoothed value.
for sample in 0..100 {
    let input_value = sample as f32;   // Dummy value, read some real value from somewhere
    let smoothed_value = smoother.tick(input_value);
}

Integer

use dyn_smooth::{DynamicSmootherEcoI32, I32_FRAC_BITS};

// Create an instance with suitable settings.
let base_freq = 2 << I32_FRAC_BITS;
let sample_freq = 1000 << I32_FRAC_BITS;
let sensitivity = (0.5 * ((1 << I32_FRAC_BITS) as f32)) as i32;
let mut smoother = DynamicSmootherEcoI32::new(base_freq, sample_freq, sensitivity);

// Feed an input value to the smoother and retrieve the smoothed value.
for sample in 0..100 {
    let input_value = sample as i32;   // Dummy value, read some real value from somewhere
    let smoothed_value = smoother.tick(input_value);
}

Tests

Run cargo test for the unit tests. Use the --nocapture option for additional output.

License

Published under the MIT license. All contributions to this project must be provided under the same license conditions.

Author: Oliver Rockstedt info@sourcebox.de

Structs

DynamicSmootherEcoF32

Efficient variant of the smoother using f32.

DynamicSmootherEcoI32

Efficient variant of the smoother using i32.

Constants

I32_FRAC_BITS

Number of fractional bits for the i32 implementation.