STCC4 Rust Driver

A Rust no-std driver for the Sensirion STCC4 CO2 sensor with blocking and async APIs.

Description

This library provides a platform-agnostic Rust interface for the STCC4 CO2 sensor over I2C. It is designed for embedded, no-std environments and supports both blocking and async access patterns based on embedded-hal and embedded-hal-async.

Supported features

All supported features are available in both blocking and async mode.

Start/stop continuous measurement
Single-shot measurement
Read measurement data (CO2, temperature, humidity, status)
Set RHT compensation values (external sensor)
Set pressure compensation
Sleep / wake
Conditioning
Soft reset (general call)
Factory reset
Self test
Enable/disable testing mode
Forced recalibration (FRC)
Read product ID and serial number

Rust features

async (default): Enables async support using embedded-hal-async
defmt: Enables defmt::Format derives and adds defmt logging statements
serde: Enables serde support for public data types (no std features)

Dependencies

embedded-hal for blocking I2C and delays
embedded-hal-async for async I2C and delays (gated by async feature)
defmt and serde are optional and controlled by features

For tests, the crate uses embedded-hal-mock and a minimal async mock implementation.

Usage

Add the crate to your Cargo.toml:

[dependencies]
stcc4 = "0.1.0"

Blocking example

use stcc4::blocking::Stcc4;

# fn example<I2C, D>(i2c: I2C, delay: D)
# where
#     D: embedded_hal::delay::DelayNs,
#     I2C: embedded_hal::i2c::I2c,
# {
let mut stcc4 = Stcc4::new(delay, i2c);

stcc4.start_continuous_measurement().ok();
let measurement = stcc4.read_measurement().ok();
stcc4.stop_continuous_measurement().ok();
# }

Async example

use stcc4::asynchronous::Stcc4;

# async fn example<I2C, D>(i2c: I2C, delay: D)
# where
#     D: embedded_hal_async::delay::DelayNs,
#     I2C: embedded_hal_async::i2c::I2c,
# {
let mut stcc4 = Stcc4::new(delay, i2c);

stcc4.start_continuous_measurement().await.ok();
let measurement = stcc4.read_measurement().await.ok();
stcc4.stop_continuous_measurement().await.ok();
# }

Testing

Run unit tests:

cargo test

Generate coverage (HTML):

cargo llvm-cov --html --open

Notes

Default I2C address is 0x64, alternate is 0x65.
The exit_sleep_mode and perform_soft_reset commands are not acknowledged by the sensor, and the driver handles this accordingly.
Temperature and humidity values in measurements are reported by an external SHT4x sensor; use set_rht_compensation if not using the STCC4’s dedicated controller interface for SHT4x.

License

This library is licensed under either of:

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

at your option.

Contribution

Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in this work is dual licensed as above, without any additional terms or conditions.

Change Log

Version 0.1.0 - Initial release

stcc4 0.1.0