Arduino - DHT11 - LCD

We will learn how to program Arduino to read temperature and humidity from DHT11 module and display them on LCD I2C.

Hardware Required

1	×	Arduino UNO or Genuino UNO
1	×	USB 2.0 cable type A/B (for USB-A PC)
1	×	USB 2.0 cable type C/B (for USB-C PC)
1	×	LCD I2C
1	×	DHT11 Temperature Humidity Sensor Module
1	×	Jumper Wires
1	×	(Recommended) Screw Terminal Block Shield for Arduino Uno
1	×	(Recommended) Breadboard Shield For Arduino Uno
1	×	(Recommended) Enclosure For Arduino Uno

Or you can buy the following sensor kits:

1	×	DIYables Sensor Kit (30 sensors/displays)
1	×	DIYables Sensor Kit (18 sensors/displays)

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Additionally, some links direct to products from our own brand, DIYables.

About DHT11 and LCD

If you do not know about DHT11 sensor and LCD (pinout, how it works, how to program ...), learn about them in the following tutorials:

Wiring Diagram

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Arduino Code - DHT11 Sensor - LCD I2C

/* * Created by ArduinoGetStarted.com * * This example code is in the public domain * * Tutorial page: https://arduinogetstarted.com/tutorials/arduino-dht11-lcd */ #include <LiquidCrystal_I2C.h> #include <DHT.h> #define DHT11_PIN 2 LiquidCrystal_I2C lcd(0x27, 16, 2); // I2C address 0x27 (from DIYables LCD), 16 column and 2 rows DHT dht11(DHT11_PIN, DHT11); void setup() { dht11.begin(); // initialize the sensor lcd.init(); // initialize the lcd lcd.backlight(); // open the backlight } void loop() { delay(2000); // wait a few seconds between measurements float humi = dht11.readHumidity(); // read humidity float tempC = dht11.readTemperature(); // read temperature lcd.clear(); // check if any reads failed if (isnan(humi) || isnan(tempC)) { lcd.setCursor(0, 0); lcd.print("Failed"); } else { lcd.setCursor(0, 0); // start to print at the first row lcd.print("Temp: "); lcd.print(tempC); // print the temperature lcd.print((char)223); // print ° character lcd.print("C"); lcd.setCursor(0, 1); // start to print at the second row lcd.print("Humi: "); lcd.print(humi); // print the humidity lcd.print("%"); } }

※ NOTE THAT:

The I2C address of LCD can vary according to the manufacturers. In the code, we used 0x27 that is specified by DIYables manufacturer

Quick Steps

Connect Arduino to PC via USB cable
Open Arduino IDE, select the right board and port
Navigate to the Libraries icon on the left bar of the Arduino IDE.
Search “DHT”, then find the DHT sensor library by Adafruit
Click Install button to install the library.

You will be asked for intalling some other library dependencies
Click Install All button all library dependencies.

Search “LiquidCrystal I2C”, then find the LiquidCrystal_I2C library by Frank de Brabander
Click Install button to install LiquidCrystal_I2C library.

Copy the above code and open with Arduino IDE
Click Upload button on Arduino IDE to upload code to Arduino
Make enviroment around sensor hotter or colder
See the result in LCD

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If LCD displays nothing, see Troubleshooting on LCD I2C

Video Tutorial

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