Si7021-T-RH  

A Rust crate for Silicon Labs Si70xx series sensor (7013, 7020, 7021)

https://github.com/marvinrobot42/si7021-t-rh.git

The Si7013, 7020, 7021 sensor relative humidity and temperature sensor with I2C interface.

All I2C API functions are implemented.

Features

• uses embedded-hal version 1.0.x
• async support included (see examples folder in repository for embassy-async ESP32-C6 example)
• designed for embedded use (ESP32-C3, -C6 and -S3 and Raspberry Pi)
• ESP32 RISC V and Raspberry Pi examples included
• enable/disable builtin heater for clearing condensation or frost (when not reading temperature)
• configurable heater power level
• reads device model number, serial numbers and firmware version
• an easy to use Measurements struct
• no_std embedded compatible

Notes

Developed using Adafruit Si7021 STEMMA QT (QWIIC) model: https://www.adafruit.com/product/3251

Recent version history

• 0.1.6 Updated Cargo.toml
• 0.1.5 Fixed messed up Cargo.toml file
• 0.1.4 Added async support, cleaned out compiler warnings
• 0.1.3 Updated README.md
• 0.1.2 Fixed repo name (whoops it is s17021-t-rh instead of si7021)
• 0.1.1 Fixed README.md
• 0.1.0 Initial release

Usage

Add the dependency to Cargo.toml.

[dependencies.si7021-t-rh]
version = "0.1"

1. Create a hardward specific I²C driver interface and delay function
2. Create an Si7021 struct with the I²C interface and a delay function as parameters.
3. Initialize the Si7021 instance 4.a Read relative humidity 4.b Read temperature or
4. Call read_measurements() fn which return both relative humdity and temperature faster than call the seperate methods due to Si70xx "Read Temperature Value from Previous RH Measurement function"

Simple Example

A more complete example is in the repository examples path

use anyhow::Result;  // add dependency for this
use si7021_t_rh::Si7021;
use log::{info, error};

...


fn main() -> Result<()> {

  ...as per your hardware hal, below is ESP32-C3 - C6 style

  let peripherals = Peripherals::take().unwrap();
  let pins = peripherals.pins;
  let sda = pins.gpio6; // esp32-c3  has pins.gpio0 , check your board schematic
  let scl = pins.gpio7; // esp32-c3  haspins.gpio1, check your board schematic
  let i2c = peripherals.i2c0;
  let config = I2cConfig::new().baudrate(400.kHz().into());
  let i2c_bus = I2cDriver::new(i2c, sda, scl, &config)?;

  let mut delay: Delay = Default::default();   // your hardware delay from use ...
  let mut my_si7021 = Si7021::new(i2c_bus, delay);
  my_si7021.init_device().unwrap();
  FreeRtos::delay_ms(250);  // or your sleep function here

  loop {
    // the read_measurements() method is a little faster (-30 msec) than reading humidity and temperature separately
    log::info!("Si70xx measurements are {:#?}", my_si7021.read_measurements().unwrap());
    FreeRtos::delay_ms(10000);
  }

}
    

For async set si7021-t-rh dependency features = ["async"] and Si7021::new method requires async I2C and delay

parameters. Default features is sync (blocking)

License

You are free to copy, modify, and distribute this application with attribution under the terms of either

• Apache License, Version 2.0 (LICENSE-Apache-2.0 or https://opensource.org/licenses/Apache-2.0)
• MIT license (LICENSE-MIT or https://opensource.org/licenses/MIT)

at your option.

This project is not affiliated with nor endorsed in any way by Silicon Labs or Adafruit.