GitHub - michaelbeaumont/dht-sensor: Rust embedded-hal based driver for the DHT11/DHT22 sensor (original) (raw)

DHT11/DHT22 sensor driver

This library provides a platform-agnostic driver for the DHT11 and DHT22 sensors.

Use one of two functions dht11::blocking::read and dht22::blocking::read to get a reading.

Usage

The only prerequisites are an embedded-hal implementation that provides:

• DelayNs-implementing type, for example Cortex-M microcontrollers typically use the SysTick.
• InputPin and OutputPin-implementing type, for example an Output<OpenDrain> from stm32f0xx_hal.

When initializing the pin as an output, the state of the pin might depend on the specific chip used. Some might pull the pin low by default causing the sensor to be confused when we actually read it for the first time. The same thing happens when the sensor is polled too quickly in succession. In both of those cases you will get a DhtError::Timeout.

To avoid this, you can pull the pin high when initializing it and polling the sensor with an interval of at least 500ms (determined experimentally). Some sources state a refresh rate of 1 or even 2 seconds.

Example

See the following examples for how to use the library.

Blocking API

• stm32f051r8

Async API

• stm32f051r8
• stm32f303vc

Release mode may be required

Compiling in debug mode may disturb the timing-sensitive parts of this crate and ultimately lead to failure. In this case, you will likely receive a Timeout error. Try compiling with --release instead.

Tests

To run the tests, use something like cargo test --lib --target x86_64-unknown-linux-gnu.