SENSORS/ACTUATORS

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Arduino - Temperature Humidity Sensor - LCD

We will learn how to:

Read temperature and humidity from DHT11 sensor and display on LCD I2C
Read temperature and humidity from DHT22 sensor and display on LCD I2C

Hardware Required

1	×	Arduino UNO or Genuino UNO
1	×	USB 2.0 cable type A/B
1	×	LCD I2C
1	×	Temperature and Humidity Sensor DHT11
1	×	Jumper Wires
1	×	(Optional) 9V Power Adapter for Arduino
1	×	(Recommended) Screw Terminal Block Shield for Arduino Uno
1	×	(Optional) Transparent Acrylic Enclosure For Arduino Uno

You can use DHT22 sensor instead of DHT11 sensor.

Or you can buy the following sensor kit:

DIYables Sensor Kit 30 types, 69 units

Please note: These are Amazon affiliate links. If you buy the components through these links, We will get a commission at no extra cost to you. We appreciate it.

About DHT11, DHT22 and LCD

If you do not know about DHT11, DHT22 temperature sensor and LCD (pinout, how it works, how to program ...), learn about them in the following tutorials:

Wiring Diagram

Arduino - DHT11 Module LCD Wiring

This image is created using Fritzing. Click to enlarge image

Arduino - DHT22 Module LCD Wiring

Arduino DHT22 temperature and humidity LCD Wiring Diagram

This image is created using Fritzing. Click to enlarge image

Real wiring for DHT11

This image is created using Fritzing. Click to enlarge image

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-temperature-humidity-sensor-lcd */ #include <LiquidCrystal_I2C.h> #include "DHT.h" #define DHTPIN 2 #define DHTTYPE DHT11 LiquidCrystal_I2C lcd(0x27, 16, 2); // I2C address 0x27 (from DIYables LCD), 16 column and 2 rows DHT dht(DHTPIN, DHTTYPE); void setup() { dht.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 = dht.readHumidity(); // read humidity float tempC = dht.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

This image is created using Fritzing. Click to enlarge image

The above code also work for Arduino Nano. A grandfather, who learns through this tutorial to guide his grandchild has tested this code with Arduino Nano and send us the result like below:

Arduino display temperature humidity on LCD

If LCD displays nothing, see Troubleshooting on LCD I2C

Arduino Code - DHT22 Sensor - LCD I2C

/* * Created by ArduinoGetStarted.com * * This example code is in the public domain * * Tutorial page: https://arduinogetstarted.com/tutorials/arduino-temperature-humidity-sensor-lcd */ #include <LiquidCrystal_I2C.h> #include "DHT.h" #define DHTPIN 2 #define DHTTYPE DHT22 LiquidCrystal_I2C lcd(0x27, 16, 2); // I2C address 0x27 (from DIYables LCD), 16 column and 2 rows DHT dht(DHTPIN, DHTTYPE); void setup() { dht.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 = dht.readHumidity(); // read humidity float tempC = dht.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:

Code for DHT11 and DHT22 are identical except for one line of code. Library for DHT11 and DHT22 are the same.

Video Tutorial

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The Best Arduino Starter Kit

See the best Arduino kit for beginner

Arduino - Temperature Humidity Sensor - LCD

Hardware Required

About DHT11, DHT22 and LCD

Wiring Diagram

Arduino - DHT11 Module LCD Wiring

Arduino - DHT22 Module LCD Wiring

Real wiring for DHT11

Arduino Code - DHT11 Sensor - LCD I2C

Quick Steps

Arduino Code - DHT22 Sensor - LCD I2C

Video Tutorial

The Best Arduino Starter Kit

See Also