Rusty Coral Envinronmental Sensors

Rust drivers for the Google Coral Environmental Sensor Board. Developed on a Raspberry Pi. Provides C bindings.

The crate bundles together drivers that allow readings from:

Humidity + Temperature: Texas Instruments HDC2010 with help from hdc20xx crate.
Ambient Light: Texas Instruments OPT3002 with help from opt300x crate.
Barometric Pressure: Bosch BMP280 with help from bmp280 crate.

Usage

You will need to explicitly list the following under [dependencies] in your Cargo.toml:

coralenv = { git = "https://github.com/bernardoaraujor/coralenv", branch = "main"}

Then, simply declare extern crate coralenv;, and call one of the four functions:

coralenv::temperature()
coralenv::humidity()
coralenv::light()
coralenv::pressure()

All functions will return a f32 with the respective reading. For example:

extern crate coralenv;

fn main() {
    println!("Temperature: {} °C", coralenv::temperature());
    println!("Humidity: {} %", coralenv::humidity());
    println!("Ambient Light: {} lux", coralenv::light());
    println!("Pressure: {} kPa", coralenv::pressure());
}

which generates:

Temperature: 41.38214 °C
Humidity: 23.078918 %
Ambient Light: 70.72 lux
Pressure: 100.26103 kPa

C bindings

Makefile and main.c show how to link against target/debug/libcoralenv.a.

$ make
$ ./main 
Temperature: 37.575378 °C
Humidity: 26.179504 %
Ambient Light: 70.800003 lux
Pressure: 100.337738 kPa

bmp280 kernel module

It might be the case that you run into the following error message:

thread '<unnamed>' panicked at 'Failed to build device: I2cError(Nix(Sys(EBUSY)))', lib.rs:47:10
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
fatal runtime error: failed to initiate panic, error 2788546640
Aborted

That is because the bmp280_i2c module has been loaded automatically into the kernel during boot. Run the following command in order to unload the kernel module:

$ sudo rmmod bmp280_i2c

and then your code should work just fine.

Warning ⚠️

I'm a total Rust n00b. This crate is just a small experiment, and things are silly and ugly. Real credit goes to natemara and eldruin for their work in the original drivers.