# ahrs-rs

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A Rust port of Sebastian Madgwick's [AHRS algorithm](https://x-io.co.uk/open-source-imu-and-ahrs-algorithms/).

[Documentation](https://docs.rs/ahrs)

## Usage

Add ahrs-rs to your `Cargo.toml`:

```toml
[dependencies]
ahrs = "0.7"
```

Here's a simple example that updates the filter state with arbitrary sensor data:

```rust
use ahrs::{Ahrs, Madgwick};
use nalgebra::Vector3;
use std::f64;

fn main() {
    // Initialize filter with default values
    let mut ahrs = Madgwick::default();

    // Obtain sensor values from a source
    let gyroscope = Vector3::new(60.1, 30.2, 20.3);
    let accelerometer = Vector3::new(0.1, 0.2, 0.3);
    let magnetometer = Vector3::new(0.5, 0.6, 0.7);

    // Run inputs through AHRS filter (gyroscope must be radians/s)
    let quat = ahrs
        .update(
            &(gyroscope * (f64::consts::PI / 180.0)),
            &accelerometer,
            &magnetometer,
        )
        .unwrap();
    let (roll, pitch, yaw) = quat.euler_angles();

    // Do something with the updated state quaternion
    println!("pitch={}, roll={}, yaw={}", pitch, roll, yaw);
}
```

Crate [nalgebra](https://crates.io/crates/nalgebra) is also needed as a dependency for its algebraic types `Vector3` and `Quaternion`.

## Feature flags

### `field_access`

Gives [im]mutable access to inner algorithm struct fields that aren't normally exposed. The exposed
API is considered unstable for the time-being, but is nevertheless a useful feature. For example:

```rust
use ahrs::Madgwick;

let mut ahrs = Madgwick::default();

#[cfg(feature = "field_access")]
{
    let sample_period: &mut f64 = ahrs.sample_period_mut();
    *sample_period = 0.5;
}
```


## License

MIT