CODEWITHSUNDEEP
rustraspberry-pi4
frave
frave

Reputation: 31

Reading the DS18B20 temperature sensor with this Rust function

sorry, i'm a complete newbie to Rust. I try to read the temp from the sensor mentioned above on a Raspberry Pi using the code provided on this site: https://github.com/fuchsnj/ds18b20

Actually, i want to call the function

get_temperature

but i have no idea how to declare the parameters, especially delay and one_wire_bus. I was able to resolve all the 'namespaces' or name bindings (sorry, coming from C++) but got stuck with the parameters. Can someone give me an example how to call and use this function like this:

use ds18b20::{Resolution, Ds18b20};
use embedded_hal::blocking::delay::{DelayUs, DelayMs};
use embedded_hal::digital::v2::{OutputPin, InputPin};
use one_wire_bus::{self, OneWire, OneWireResult};
use core::fmt::Debug;
use std::io::Write;

fn main() {
    
    let mut delay = ?????;
    let mut one_wire_bus = ?????;
    let mut tx = ?????;  //&mut Vec::new();
    
    let temp = get_temperature(delay, tx, one_wire_bus);

    ...
    //do something whit the temp
    ...
}

This is the implementation of the function from the website

fn get_temperature<P, E>(
    delay: &mut (impl DelayUs<u16> + DelayMs<u16>),
    tx: &mut impl Write,
    one_wire_bus: &mut OneWire<P>,
) -> OneWireResult<(), E>
    where
        P: OutputPin<Error=E> + InputPin<Error=E>,
        E: Debug
{
    // initiate a temperature measurement for all connected devices
    ds18b20::start_simultaneous_temp_measurement(one_wire_bus, delay)?;

    // wait until the measurement is done. This depends on the resolution you specified
    // If you don't know the resolution, you can obtain it from reading the sensor data,
    // or just wait the longest time, which is the 12-bit resolution (750ms)
    Resolution::Bits12.delay_for_measurement_time(delay);

    // iterate over all the devices, and report their temperature
    let mut search_state = None;
    loop {
        if let Some((device_address, state)) = one_wire_bus.device_search(search_state.as_ref(), false, delay)? {
            search_state = Some(state);
            if device_address.family_code() != ds18b20::FAMILY_CODE {
                // skip other devices
                continue;
            }
            // You will generally create the sensor once, and save it for later
            let sensor = Ds18b20::new(device_address)?;

            // contains the read temperature, as well as config info such as the resolution used
            let sensor_data = sensor.read_data(one_wire_bus, delay)?;
            writeln!(tx, "Device at {:?} is {}°C", device_address, sensor_data.temperature);
        } else {
            break;
        }
    }
    Ok(())
}

Upvotes: 2

Views: 804

Answers (1)

Maicmi
Maicmi

Reputation: 1104

There is an example here. https://github.com/awendland/rpi-ds18b20-rust

This is a toy program written in Rust for retrieving temperature data from a DS18B20 sensor attached via the one-wire interface to a Raspberry Pi.

Upvotes: 1

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