🌡️ dht11-driver

📖 Table of Contents

📍 Overview
📦 Features
📂 Repository Structure
🚀 Getting Started
🛠 Technical Details
📃 License

📍 Overview

This project provides a highly optimized, no_std Rust driver for the DHT11 temperature and humidity sensor.

Designed with safety and precision in mind, it supports both hardware-accelerated timing via ARM DWT and a portable software-based timing engine.

📦 Features

Component	Description
Agnostic	Platform-independent core; works on any MCU via `embedded-hal`.
Safety	Uses Typestates to prevent reading from an uninitialized sensor.
Precision	DWT hardware support for sub-microsecond pulse measurement.
Observability	Native integration with `defmt` for zero-overhead logging.

📂 Repository Structure

└── dht11-driver/

    ├── src/

    │   ├── lib.rs            # Core driver and Typestate logic

    │   └── examples/         # STM32F407 reference implementations

    │       ├── stm32f407_dwt.rs

    │       └── stm32f407_no_dwt.rs

    ├── .cargo/

    │   └── config.toml       # Runner & Linker settings

    └── Cargo.toml            # Feature gate definitions

🚀 Getting Started

1. Installation

Add the library to your Cargo.toml:

[dependencies]

dht11-driver = "0.1.2"

Or use the cargo CLI:

cargo add dht11-driver

2. Hardware Setup (STM32F407)

1. Sensor Connection: Connect the DHT11 DATA pin to PA0 on your STM32F407 Discovery/Black-Pill board.

2. Pull-Up Resistor: The DHT11 uses a single-wire bidirectional protocol. You must configure the pin as Open-Drain. A physical 4.7kΩ to 10kΩ pull-up resistor to VCC is highly recommended for signal integrity.

Running the Examples This repository includes pre-configured examples using probe-rs. Use the following commands to flash your board:

Mode	Command	Active Features
High Precision	cargo run --example stm32f407f_dwt --features use-dwt	use-dwt, use-defmt
Universal Timing	cargo run --example stm32407f_no_dwt	use-defmt

🛠 Technical Details

Typestate Safety

To eliminate logic errors—such as attempting to read data before the sensor has finished its 2-second power-on stabilization—this driver implements the Typestate Pattern. The sensor object transitions through different types in your code:

// 1. Create the driver in 'Uninitialized' state
let dht11 = DHT11::new(pin, clocks.sysclk());

// 2. Initialize
// This consumes the old state and returns the 'Initialized' version
let mut dht11 = dht11.initialize(&mut delay).expect("Initialization failed");

// 3. Only now is the .read_temp_and_hum() method available in your IDE!
let measurement = dht11.read_temp_and_hum(&mut delay);

📖 License

Distributed under the MIT License. See the LICENSE file for more information.

dht11-driver 0.1.2