DHT11 Temperature and Humidity Sensor
Overview
The **DHT11** is a low-cost digital sensor that measures both temperature and humidity. It is commonly used in environmental monitoring and control systems due to its simplicity and affordability. It provides digital output calibrated to deliver accurate readings.
Specifications
- Temperature Range: 0°C to 50°C (±2°C accuracy)
- Humidity Range: 20% to 90% RH (±5% accuracy)
- Operating Voltage: 3.3V - 5.5V
- Sampling Rate: 1 Hz (one reading per second)
- Digital Output: Serial data protocol
- Dimensions: 15mm x 12mm x 5mm
Pinout
| Pin | Name | Description |
|---|---|---|
| 1 | VCC | Power Supply (3.3V - 5.5V) |
| 2 | DATA | Serial Data Output |
| 3 | NC | No Connection (Leave Unconnected) |
| 4 | GND | Ground |
Working Principle
The **DHT11** uses a capacitive humidity sensor and a thermistor to measure the surrounding air's relative humidity and temperature. The sensor integrates these values into a calibrated digital signal, which is sent to a microcontroller through its single-wire DATA pin.
The microcontroller communicates with the sensor using a proprietary protocol. The sensor is powered by VCC and GND, while the data pin transmits information in 40-bit segments (16-bit for temperature, 16-bit for humidity, and an 8-bit checksum).
Applications
- Weather Monitoring Systems
- Home Automation and Smart Devices
- Greenhouse Monitoring
- Industrial Environmental Controls
- IoT Projects
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