Arduino DHT11 Project

Cooling system with Arduino

Purpose of this project:

In this project a cooling system will be built with Arduino. It mainly uses a DTH11 temperature sensor, fan and LCD display.

When the Arduino board detects a temperature > 28°C the fan starts to rotate until the temperature becomes < 28°C.

Necessary components

  • Arduino
  • LCD display
  • DTH11 temperature sensor
  • a small 5V fan
  • a relay
  • connecting wires


To complete the assembly, you can connect:

  For relay

  • Pin S  to PIN1 of Arduino
  • Pin (+)  to 3.3V of Arduino
  • Pin (-) to GND of Arduino
  • Pin ON to 5V PIN of Arduino

For the fan:

  • Pin (+)  to COM Pin of relay
  • Pin (-)  to GND of Arduino

For DHT11 sensor:

  • Pin DATA to Pin2 of Arduino.
  • Pin VCC  to 3.3V of Arduino
  • Pin GND to GND of Arduino

For the LCD display:

  • the SDA pin at the Arduino analog pin A4.

  • the SCL pin at the Arduino analog pin A5.

  • the VCC pin at the Arduino 5v pin.

  • the GND pin at the Arduino GND pin


This is the cooling system program.

Note: both libraries must be downloaded  DTH11 et I2c_LCD1602

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