Sensirion SHT4x Driver for Embedded HAL

A platform agnostic device driver for the Sensirion SHT4x temperature and humidity sensor family. It is based on embedded-hal traits and works in no_std environments.

In theory, it supports all of the sensor family's devices but has only been tested with the SHT40-AD1B so far.

Features

Blocking operation
Supports all commands specified in the datasheet
Explicitly borrows DelayMs for command execution so that it could be shared (among multiple sensors)
Could be instantiated with the alternative I2C address for the SHT40-BD1B
Uses fixed-point arithmetics for converting raw sensor data into measurements in SI units
- Based on I16F16 from the fixed crate
- Allows conversion to floating-point values, if needed
- Convenience methods for fixed-point conversions to milli degree Celsius or milli percent relative humidity which are commonly used by drivers for other humidity and temperature sensors from Sensirion
Optional support for defmt

Example

use sht4x::Sht4x;
// Device-specific use declarations.

let mut delay = // Device-specific initialization of delay.
let i2c = // Device-specific initialization of I2C peripheral.
let mut sht40 = Sht4x::new(i2c);

let serial = sht40.serial_number(&mut delay);
defmt::info!("serial number: {}", serial);

let measurement = sht40.measure(Precision::Low, &mut delay);
defmt::info!("measurement: {}", &measurement);

if let Ok(measurement) = measurement {
    // Convert temperature measurand into different formats for further
    // processing.
    let int: i32 = measurement.temperature_milli_celsius();
    let fixed: I16F16 = measurement.temperature_celsius();
    let float: f32 = measurement.temperature_celsius().to_num();
}

`embedded-hal-async` support

This crate has optional support for the embedded-hal-async crate, which provides async versions of the I2c and DelayNs traits. Async support is an off-by-default optional feature, so that projects which aren't using embedded-hal-async can avoid the additional dependency.

To use this crate with embedded-hal-async, enable the embedded-hal-async feature flag in your Cargo.toml:

sht4x = { version = "0.2", features = ["embedded-hal-async"] }

Once the embedded-hal-async feature is enabled, construct an instance of the Sht4xAsync struct, providing types implementing the embedded_hal_async::i2c::I2c and embedded_hal_async::delay::DelayNs traits. The Sht4xAsync struct is identical to the Sht4x struct, except that its methods are async fns.

Related Work

sensor-temp-humidity-sht40 is another driver for this sensor family.

License

Licensed under either of

Apache License, Version 2.0 (LICENSE-APACHE or http://www.apache.org/licenses/LICENSE-2.0)
MIT license (LICENSE-MIT or http://opensource.org/licenses/MIT)

at your discretion.

Contribution

Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in the work by you, as defined in the Apache-2.0 license, shall be dual licensed as above, without any additional terms or conditions.

sht4x 0.2.0