SHT31-rs  

A cargo library for the SHT31 temperature / humidity sensors

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Usage

The default sensor usage includes a blocking sensor read that blocks the current thread until the sensor does a reading.

use sht31::prelude::*;

fn main() -> Result<()> {
    // Requires an i2c connection + delay (both from embedded_hal 1.x.x)
    let sht = SHT31::new(i2c, delay);
    
    loop {
        let reading = sht.read()?;
    }
}

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Advanced Single Shot Usage

Breaks down the simple usage into two commands, one where the sensor is notified to start reading and another where the reading is requested

use sht31::prelude::*;

fn main() -> Result<()> {
    // i2c setup
    
    // Use single shot, with high accuracy, an alternate I2C address 
    // and return temp data in Fahrenheit
    let sht = SHT31::new(i2c)
        .with_mode(SingleShot::new())
        .with_accuracy(Accuracy::High)
        .with_unit(TemperatureUnit::Fahrenheit)
        .with_address(DeviceAddr::AD1);

    loop {
        // Start measuring before you need the reading, 
        // this is more efficient than waiting for readings
        sht.measure()?;

        // Some other code here...

        let reading = sht.read()?;
    }
}

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Periodic Usage

Periodic mode continually reads data at a rate of the given measurements per second (MPS) and at a quality of the given Accuracy. This means that you dont have to worry about running SHT31::measure() every time you want to read data

use sht31::prelude::*;

fn main() -> Result<()> {
    // i2c setup
    
    // In periodic mode, the sensor keeps updating the reading
    // without needing to measure
    let mut sht = SHT31::new(sht_i2c)
        .with_mode(Periodic::new().with_mps(MPS::Normal))
        .with_accuracy(Accuracy::High);
    
    // Trigger the measure before running your loop to initialize the periodic mode
    sht.measure()?;
    
    loop {
        let reading = sht.read()?;
    }
}

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Periodic with Accelerated Response Time

Periodic mode has a unique mode that allows the sensor to read data at 4Hz

use sht31::prelude::*;

fn main() -> Result<()> {
    
    // Makes the sensor acquire the data at 4 Hz
    let mut sht = SHT31::new(sht_i2c)
        .with_mode(Periodic::new().with_art());
    sht.measure()?;
    
    loop {
        let reading = sht.read()?;
    }
}

---

Mode switching

This crate also supports more complex case scenarios where you might want to switch between period to single shot for example

use sht31::prelude::*;

fn main() -> Result<()> {
    // i2c setup
    
    let mut sht = SHT31::new(sht_i2c)
        .with_mode(Periodic::new());
    
    // Trigger the measure before running your loop to initialize the periodic mode
    sht.measure()?;
    
    // Do a periodic read
    let reading = sht.read()?;
    
    // Cancel the currently running command (periodic)
    sht.break_command()?;
    
    sht = sht.with_mode(SingleShot::new());
    
    sht.measure()?;
    
    let new_reading = sht.read()?;
}