Embassy DHT Sensor Library

This Rust library provides an interface for interacting with DHT1X and DHT2X temperature and humidity sensors using the Embassy framework.

test on raspberry pico (w) (RP2040) && Pico 2 (RP2350)

Getting Started

Installation

Add embassy-dht-sensor to your Cargo.toml:

[dependencies]
embassy-dht = "0.1.9"

Usage

Initialize your Raspberry Pi Pico board with Embassy. Create an instance of DHTSensor with the GPIO pin connected to your DHT sensor. Use the read method to get temperature and humidity readings.

add new feature rp2040 && rp2350

to fix the build error for rp-pac@6.0.0, the embassy-dht default-features

  default-features = ["rp2040"]

To use rp2350 feature for Pico2

embassy-dht = { version = "0.1.9", default-features=false, features = ["embedded_alloc","rp2350"] }

Example for RP2040

  //   for dht22
  use embassy_executor::Spawner;
  use defmt::*;
  use embassy_time::{Delay, Timer};
  use embassy_rp;
  use embassy_dht::dht22::DHT22;
 
  #[embassy_executor::main]
    async fn main(spawner: Spawner) {
    info!("Hello World!");
 
    let p = embassy_rp::init(Default::default());
 
    info!("set up dhtxx pin");
 
    let mut dht_pin = DHT22::new(p.PIN_22,Delay);
 
    loop {
    Timer::after_secs(1).await;
    let dht_reading = dht_pin.read().unwrap();
    let (temp, humi) = (dht_reading.get_temp(), dht_reading.get_hum());
    defmt::info!("Temp = {}, Humi = {}\n", temp,humi);
    ... the code what you write
 }
 }

  // for dht11
  use embassy_executor::Spawner;
  use defmt::*;
  use embassy_time::{Delay, Timer};
  use embassy_rp;
  use embassy_dht::dht11::DHT11;
 
  #[embassy_executor::main]
    async fn main(spawner: Spawner) {
    info!("Hello World!");
 
    let p = embassy_rp::init(Default::default());
 
    info!("set up dhtxx pin");
 
    let mut dht_pin = DHT11::new(p.PIN_22,Delay);
 
   loop {
    Timer::after_secs(1).await;
    let dht_reading = dht_pin.read().unwrap();
    let (temp, humi) = (dht_reading.get_temp(), dht_reading.get_hum());
    defmt::info!("Temp = {}, Humi = {}\n", temp,humi);
    ... the code what you write
   }
   }

//for dht20
  use embassy_executor::Spawner;
  use defmt::*;
  use embassy_time::{Delay, Timer};
  use embassy_rp;
  use embassy_dht::prelude::*;
 
  #[embassy_executor::main]
    async fn main(_spawner: Spawner) {
    info!("Hello World!");
 
    let p = embassy_rp::init(Default::default());
 
    info!("set up dhtxx i2c pin");
    let dht_sda = p.PIN_16; //I2C0 SDA
    let dht_scl = p.PIN_17; //I2C0 SCL
    let dht_i2c = i2c::I2c::new_blocking(p.I2C0, dht_scl, dht_sda, i2c::Config::default());
    let mut dht_pin = DHT20::new(dht_i2c, Delay);

 
   loop {
    Timer::after_secs(1).await;
    let dht_reading = dht_pin.read().unwrap();
    let (temp, humi) = (dht_reading.get_temp(), dht_reading.get_hum());
    defmt::info!("Temp = {}, Humi = {}\n", temp,humi);
    ... the code what you write
   }
   }

# New feature embedded_alloc

to enable it by ,add to Cargo.toml

```toml
embassy-dht = { version = "0.1.9", features= ["embedded_alloc"] }

when enable embedded_alloc we will get new fn in DHT11/DHT22 mod

pub trait DhtValueString {
     fn get_temp_str(&self) -> String;
     fn get_hum_str(&self) -> String;
}

Example for RP2350

for rp2350 need to use the crate embassy-rp from github.com

use rev="ee669ee5c57851ade034beca7cfaf81825c4c21b"

Cargo.toml

embassy-executor = { version = "0.6.0", git="https://github.com/embassy-rs/embassy", rev="ee669ee5c57851ade034beca7cfaf81825c4c21b", features = ["task-arena-size-98304", "arch-cortex-m", "executor-thread", "executor-interrupt", "defmt", "integrated-timers"] }
embassy-time = { version = "0.3.2", git="https://github.com/embassy-rs/embassy", rev="ee669ee5c57851ade034beca7cfaf81825c4c21b",features = ["defmt", "defmt-timestamp-uptime"] }
embassy-time-driver = { version = "0.1", git="https://github.com/embassy-rs/embassy", rev="ee669ee5c57851ade034beca7cfaf81825c4c21b"}
embassy-rp = { version = "0.2.0", git="https://github.com/embassy-rs/embassy", rev="ee669ee5c57851ade034beca7cfaf81825c4c21b", features = ["defmt", "unstable-pac", "time-driver", "critical-section-impl","rp235xa", "binary-info"] }
embassy-dht = { version = "0.1.9", default-features = false, features = [ "embedded_alloc"] }

[patch.crates-io]
embassy-dht = { git="https://github.com/sndnvaps/embassy-dht", rev="a020823c82bf2f10c63c2bf933ae936a233a4b29", default-features=false, features = ["embedded_alloc","rp2350"] }

...what crate you need

src/main.rs

#![no_std]
#![no_main]

use defmt::info;
use embassy_executor::Spawner;
use embassy_rp::block::ImageDef;
use embassy_rp::gpio::{Level, Output};
use embassy_rp::i2c;
use embassy_time::{Delay, Timer};

use {defmt_rtt as _, panic_probe as _};

use embassy_dht::dht22::DHT22;

#[link_section = ".start_block"]
#[used]
pub static IMAGE_DEF: ImageDef = ImageDef::secure_exe();

#[embassy_executor::main]
async fn main(_spawner: Spawner) {

    let p = embassy_rp::init(Default::default());

    info!("set up dhtxx pin");

    let mut dht_pin = DHT22::new(p.PIN_17, Delay);

    //enable on board LED
    let mut led = Output::new(p.PIN_25, Level::Low);


    loop {
        Timer::after_secs(1).await;

        let dht_reading = dht_pin.read().unwrap();

        // Perform a sensor reading
        let (temp, humi) = (dht_reading.get_temp(), dht_reading.get_hum());

       ... what you code 

        info!("led on!");
        led.set_high();
        Timer::after_millis(250).await;

        info!("led off!");
        led.set_low();
        Timer::after_millis(250).await;
    }
}

examples

https://github.com/sndnvaps/embassy-dht/tree/main/examples/picow-display-embedded-alloc

https://github.com/sndnvaps/embassy-dht/tree/main/examples/picow-display

https://github.com/sndnvaps/embassy-dht/tree/main/examples/pico2-display

Pick up idea from https://crates.io/crates/embassy-dht-sensor