The purpose of this tutorial is to learn how to make a simple Temperature and Humidity Monitoring System using the DHT11 sensor with Arduino board and 2 LEDs.

Temperature and Humidity Monitoring System components:

  • Arduino Board: Uno, Nano, Mega … ( in this tutorial I used the Arduino Nano board).
  • USB cable for the Arduino.
  • A temperature and humidity sensor DHT11.
  • Breadboard.
  • 2 LEDs.
  • Connection wires.

temperature and humidity monitoring system

The DHT11 Sensor:

  • Supports  3.3V or 5V of power supply.
  • Maximum consumption of 2.5mA (at data collection).
  • Effective in 20-80% moisture, with an accuracy of 5%.
  • Effective on the 0 to 50 ° C with an accuracy of 2 ° C.
  • Maximum sampling frequency: 1Hz.
  • Dimensions: 15.5mm x 12mm x 5.5mm.

Principle of this System:

This is a very simple system based on continuous temperature and humidity calculation and monitoring using 2 LEDs.

We decided to make this system keep the temperature between 20°C and 40°C ( 20 <= T <= 40 ). So if the temperature out of this range a green Led light.

Also we set a range of ambient humidity  25%<= H <=45%. So when the humidity out of this range Blue LED light.


The mounting is to connect the power supply (5V and GND) and a digital reading of the Arduino to the DHT11 sensor  ( you can add a resistance of 10 k ohms between the pin 1 and 2 of the sensor).

LED1 (blue LED) connected to the digital pin 13 of the Arduino and to GND.

LED2 (green LED) connected to the digital pin 12 of the Arduino and to GND.

Humidity and temperature monitoring system moleandroid

Watch the video Below to see how this system work.

Click here to download The Arduino program of Temperature and Humidity Monitoring System.


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