When it comes to detect humidity and temperature for your DIY projects then we need DHT11 sensor, it is the perfect combination of both temerature and humidity sensor and be installed anywhere. We can use this for remote weather stations or for any garden monitoring projects. We can interface this sensor with any microcontroller like 8051, AVR Microcontrollers, PIC, Arduino. Here in this tutorial we will discuss about the DHT11 senosr from basic to advanced interfacing and reading technique. It is a very small size and very perfect for every project and easy to interface.
It has following ranges and accuracy.
Humidity Range: 20-90% RH
Humidity Accuracy: ±5% RH
Temperature Range: 0-50 °C
Temperature Accuracy: ±2% °C
Operating Voltage: 3V to 5.5V
For more details you can download Datasheet From below given link.
How DHT11 Detects Humidity
There are to important components in this sensor they are electrodes that detects water vapor. It detects water wapor and measure the the resistance between two electrodes. These electrodes works together, The change in the resistance between two electrodes produces relative humidity. High relative humidity then decrease of resistance between the electrodes, when there is a lower relative humidity then it increases the resistance between these two electrodes.
How DHT11 Detects Temperature DHT11 holds NTC temperature sensor called thermistor inside it, which is a surface mounted NTC inbuilt sensor inside it. It silently studies the environment through the internal circuitery and detects the temperature from the environment.