🌡️ DHT22 Sensor Driver for Pico In C

This repository contains a driver for the DHT22 temperature and humidity sensor for use with the Raspberry Pi Pico. The driver communicates with the DHT22 sensor over a single data line using specific timing to read the temperature and humidity values.

🖼️ Single-bus Communication Diagram

The diagram above illustrates the signal timing for single-bus communication between the host (Raspberry Pi Pico) and the DHT22 sensor.

📌 AM2302 Pin Diagram

These images show the pin assignments for the AM2302 sensor. Make sure to connect them correctly to your Raspberry Pi Pico.

🛠️ Usage

Before using this driver, ensure that the Raspberry Pi Pico SDK is installed and the PICO_SDK_PATH environment variable is set.

🏗️ Building the Project

To build the project, use the following commands:

mkdir build
cd build
cmake ..
make

This will compile the driver and create an executable.

🔧 Integration in Your Project

To integrate the DHT22 driver into your own project:

1. Copy the DHT22-master directory into your project.
2. In your CMakeLists.txt, add the directory of the DHT22 driver to target_include_directories.
3. Include DHT22.h in your add_executable command.

📊 Example Data Calculation

The DHT22 sensor sends data in 5 bytes, where:

• The first two bytes represent the humidity percentage.
• The next two bytes represent the temperature in Celsius.
• The last byte is a checksum for data integrity.

Here's an example from the datasheet:

Received Data:
0000 0010 1001 0010 0000 0001 0000 1101 1010 0010

Calculated Checksum:
0000 0010 + 1001 0010 + 0000 0001 + 0000 1101 = 1010 0010 (Parity bit)

The received data is correct:
Humidity: 65.8% RH
Temperature: 26.9°C

Note: If the highest bit of the temperature data is 1, it indicates a negative temperature value.

📝 Special Instructions

For temperatures below 0°C, the highest bit of the temperature data will be set. For example, a temperature of -10.1°C will be represented as:

1 000 0000 0110 0101

🤝 Contribution

Feel free to fork this project and contribute to improving the driver. If you encounter any issues or have suggestions, please open an issue in the repository.

📜 License

This project is licensed under the MIT License - see the LICENSE file for details.