LTR-303ALS

This is a platform-agnostic Rust driver for the LTR-303 Ambient Light Sensor using embedded-hal traits.

Supported devices

Tested with the following sensor(s):

• LTR-303ALS-01

Status

• Starting a measurement with configurable gain, integration time and measurement rate. See: start_measurement()
• Polling for new data. See: data_ready()
• Checking latest measurement status. See: get_status()
• Reading the latest illuminance value in lux. See: get_lux_data()
• Putting the sensor in standby. See: standby()
• Reading part ID and manufacturer ID. See: get_part_id() and get_mfc_id()
• Option to pass a delay function to the driver. Similar to the opt300x driver.
• Sensor reset in case of error.
• Wait for sensor start-up before triggering measurement after cold startup (100ms)
• Interrupts.

Examples

On Linux using i2cdev:

use linux_embedded_hal::I2cdev;
use ltr303::{LTR303, LTR303Config};

fn main() {
    let dev = I2cdev::new("/dev/i2c-1").unwrap();
    let mut sensor = LTR303::init(dev);
    let config = LTR303Config::default();
    sensor.start_measurement(&config).unwrap();

    loop {
        while sensor.data_ready().unwrap() != true {
            // Wait for measurement ready
        }

        let lux_val = sensor.get_lux_data().unwrap();
        println!("LTR303 current lux phys: {}", lux_val.millilux_phys() as f32 / 1000.0);
    }
}

---

On an ESP32-based development board:

use embedded_hal::prelude::*;
use esp_idf_sys as _;
use esp_idf_hal::{delay::FreeRtos, i2c};
use esp_idf_hal::peripherals::Peripherals;
use ltr303::{LTR303, LTR303Config};

fn main() {
    esp_idf_sys::link_patches();

    let _peripherals = Peripherals::take().unwrap();
    // The i2c pins
    let sda = _peripherals.pins.gpio4.into_input_output().unwrap();
    let scl = _peripherals.pins.gpio6.into_output().unwrap();

    let _cfg = i2c::config::MasterConfig::new().baudrate(10000.into());
    let _i2c = i2c::Master::new(_peripherals.i2c0, i2c::MasterPins { sda, scl }, _cfg).unwrap();

    let mut ltr303 = LTR303::init(_i2c);
    let ltr303_config =
        LTR303Config::default().with_integration_time(ltr303::IntegrationTime::Ms400);
    ltr303.start_measurement(&ltr303_config).unwrap();

    loop {
        while ltr303.data_ready().unwrap() != true {
            // Wait for measurement ready
        }

        let lux_val = ltr303.get_lux_data().unwrap();
        println!("LTR303 current millilux phys: {}", lux_val.millilux_phys());

        FreeRtos.delay_ms(3000_u32);
    }
}

Development

For easy development, a flake.nix is provided. Make sure you have Nix installed, as well as the flake command enabled (for example by adding experimental-features = nix-command flakes to ~/.config/nix/nix.conf) and then simply run

nix develop

inside the project folder to have a complete build and development environment with all required dependencies for ltr303-rs.