Crate scd41_embedded 

no_std driver for the Sensirion SCD41 CO₂ / temperature / humidity sensor.

scd41-embedded is a small, no_std driver for the Sensirion SCD41 (SCD4x family), built on top of the embedded-hal traits.

This crate is a clean reimplementation inspired by existing Rust work in this space (notably scd4x: https://github.com/hauju/scd4x-rs), while following the same async feature conventions used by the other drivers in this workspace.

What this crate provides

• A blocking driver: Scd41
• Basic configuration + measurement methods
• Optional async API behind the async feature: [r#async::Scd41Async]

Blocking usage

use scd41_embedded::{Error, Scd41};

fn example<I2C, D, E>(i2c: I2C, delay: D) -> Result<(), Error<E>>
where
    I2C: embedded_hal::i2c::I2c<Error = E>,
    D: embedded_hal::delay::DelayNs,
    E: embedded_hal::i2c::Error,
{
    let mut scd = Scd41::new(i2c, delay);
    scd.start_periodic_measurement()?;

    loop {
        if scd.data_ready()? {
            let m = scd.measurement()?;
            // m.co2_ppm
            // m.temperature_c
            // m.relative_humidity_percent
            break;
        }
    }

    Ok(())
}

Async usage

Enable the async feature to use the async driver API in [r#async]. The async API uses embedded-hal-async and requires async implementations of both I2c and DelayNs.

use scd41_embedded::{Error};
use scd41_embedded::r#async::Scd41Async;

pub async fn example<I2C, D, E>(i2c: I2C, delay: D) -> Result<(), Error<E>>
where
    I2C: embedded_hal_async::i2c::I2c<Error = E>,
    D: embedded_hal_async::delay::DelayNs,
    E: embedded_hal::i2c::Error,
{
    let mut scd = Scd41Async::new(i2c, delay);
    scd.start_periodic_measurement().await?;

    loop {
        if scd.data_ready().await? {
            let _m = scd.measurement().await?;
            break;
        }
    }
    Ok(())
}

Notes

• The SCD41 uses a per-word CRC byte (Sensirion CRC-8). This crate validates CRCs on reads.
• Some commands are not intended to be used while periodic measurement is running.

Modules

types

Data types.

Structs

Scd41

Blocking SCD41 driver. This is your main interface to the sensor.

Enums

Error

Driver error.

Constants

DEFAULT_ADDRESS

Default 7-bit I2C address of the SCD41.