In-Depth: Interfacing DHT11 and DHT22 Sensors with Arduino

This project interfaces a DHT11 or DHT22 temperature and humidity sensor with an Arduino Uno to capture environmental data and display it. The DHT sensors utilize a capacitive humidity sensor and a thermistor to measure the surrounding air, outputting a digital signal through a single data pin. Because the data line operates on a single-wire bi-directional protocol requiring precise timing, a 10kΩ pull-up resistor is placed between the data line and the 5V power supply to ensure signal integrity and proper logic levels. The Arduino Uno reads this digital stream using the DHTlib Library by Rob Tillaart, which handles the complex pulse-width timing required by the sensor. Once processed by the microcontroller, the parsed temperature and relative humidity values can be transmitted back to a computer via the serial monitor or optionally routed to a 16x2 character LCD connected to the breadboard using jumper wires. The entire circuit is prototyped on a standard breadboard, powered by the Arduino's regulated voltage outputs, allowing continuous and real-time environmental monitoring.