bme680-driver 0.2.1

A type-safe, no_std driver for the Bosch BME680 environmental sensor using embedded-hal
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# bme680-driver


[![Crates.io](https://img.shields.io/crates/v/bme680-driver.svg)](https://crates.io/crates/bme680-driver)
[![Documentation](https://docs.rs/bme680-driver/badge.svg)](https://docs.rs/bme680-driver)
[![License](https://img.shields.io/badge/license-MIT%2FApache--2.0-blue.svg)](https://github.com/Wkesther2/bme680-driver)

## Table of Contents

- [Overview](#overview)
- [Features](#features)
- [Repository Structure](#repository-structure)
- [Installation](#installation)
- [Quick Start](#quick-start-stm32-example)
- [Units & Precision](#units-and-precision)
- [License](#license)

---

## Overview


A type-safe, `no_std` Rust driver for the **Bosch BME680** environmental sensor. It provides high-level access to temperature, humidity, atmospheric pressure, and gas resistance measurements using the `embedded-hal` traits.

---

## Features


- **Power Saving**: Individually enable/disable gas, pressure, temperature, or humidity measurements to reduce power consumption.
- **Typestate Pattern**: Prevents illegal sensor states and ensures correct initialization.
- **Fixed-Point Arithmetic**: High-performance compensation formulas without the need for a floating-point unit (FPU).
- **Type-Safe Units**: Uses custom types like `Celsius` and `Milliseconds` to prevent unit-mixing errors.
- **No-Std**: Suitable for all bare-metal microcontrollers (STM32, ESP32, AVR, etc.).

---

## Repository Structure


```sh
└── bme680-driver/
    ├── src/
    │   ├── lib.rs
    │   └── calc.rs
    ├── examples/
    │   └── stm32f407.rs
    ├── .cargo/
    │   └── config.toml
    └── Cargo.toml
```

---

## Installation


Add this to your `Cargo.toml`:

```toml
[dependencies]
bme680-driver = "0.2.1"
```

---

## Quick Start (STM32 Example)


```rust
use bme680_driver::*;

// Initialize I2C and Delay from your HAL...
// let i2c = ...
// let mut delay = ...

let bme = Bme680::new(i2c, 0x76);
let mut bme = bme.init(&mut delay).expect("Failed to init BME680");

let mut config = Config {
    osrs_config: OversamplingConfig {
        temp_osrs: Oversampling::X2,
        hum_osrs: Oversampling::X1,
        // Example: Disable pressure measurement to save power and time
        pres_osrs: Oversampling::Skipped,
    },
    iir_filter: IIRFilter::IIR0,
    // Enable gas measurement by providing a profile (wrap in Some)
    gas_profile: Some(GasProfile {
        index: GasProfileIndex::Profile0,
        target_temp: Celsius(300),
        wait_time: Milliseconds(300),
    }),
    ambient_temp: Celsius(2300), // 23.00 °C initial guess
};

bme.configure_sensor(&mut config).unwrap();

loop {
    // Perform measurement (waits automatically for heating if enabled)
    let data = bme.read_new_data(&mut delay).unwrap();
    
    // Use helper methods to format data (no floats needed!)
    let (temp_whole, temp_frac) = data.temp.split();
    let (hum_whole, hum_frac) = data.hum.split();
    
    // Log formatted data (e.g., via defmt)
    defmt::println!("Temperature:    {}.{} °C", temp_whole, temp_frac);
    defmt::println!("Humidity:       {}.{} %", hum_whole, hum_frac);
    defmt::println!("Gas Resistance: {}  Ohm", data.gas.0);
    
    // Pressure was skipped, so it returns default/zero values
    // defmt::println!("Pressure: Skipped"); 
    
    defmt::println!("");
    
    // Dynamically update heater profile with current ambient temperature.
    // We only do this if gas measurement is actually enabled.
    if let Some(profile) = config.gas_profile {
        // We access the raw value (.0) to wrap it into Celsius
        bme.set_gas_heater_profile(profile, Celsius(data.temp.0)).unwrap();
    }
    
    delay.delay_ms(5000);
}
```

---

## Units and Precision


| Measurement | Unit | Scaling | Example |
| :--- | :--- | :--- | :--- |
| **Temperature** | **Celsius** | T * 100 | 2350 = 23.50 °C |
| **Humidity** | **% Relative Humidity** | H * 1000 | 45123 = 45.123 % |
| **Pressure** | **Pascal (Pa)** | 1.0 | 101325 Pa = 1013.25 hPa |
| **Gas Resistance** | **Ohm (Ω)** | 1.0 | 45000 = 45 kΩ |

---

## 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 option.