dht11 temperature and humidity sensor

DHT11 Temperature and Humidity Sensor

The DHT11 Temperature and Humidity Sensor senses, measures and regularly reports the relative humidity in the air. It measures both moisture and air temperature. The warmer the air is, more moisture it can hold, so relative humidity changes with fluctuations in the temperature.

Humidity sensors detect the relative humidity of immediate environments in which they are placed. They measure both moisture and temperature in the air and express relative humidity as a percentage of the ratio of moisture in the air to the maximum amount that can be held in the air at the current temperature. As the air becomes hotter, it holds more moisture, so the relative humidity changes with the temperature.DHT11 Temperature and Humidity Sensor

Hardware Connections  

  • Vcc to 5V of arduino
  • Gnd to Gnd of arduino
  • Dout to A0(Analog 0 pin) of arduino

Difference between DHT11 and DHT22

The different versions of the DHT sensor, they are similar in look and have the same pinout configuration, but have different characteristics and specifications:

DHT11

  • Cheaper in cost
  • The required power supply of 3 to 5v.
  • 5% accuracy for humidity reading and 20-80% good.
  • ±2°C accuracy for temperature reading.
  • Max 1 Hz sampling rate (once every second)
  • Size 15.5mm x 12mm x 5.5mm

DHT22

  • Cost more than DHT11.
  • The required power supply of 3 to 5v.
  • 2-5% accuracy for humidity reading and 0-100% good.
  • ±0.5°C accuracy for temperature reading and -40 to 125°C good.
  • Max 0.5 Hz sampling rate (once every 2 seconds)
  • Size 15.1mm x 25mm x 7.7mm

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