ESP32 - 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	×	ESP-WROOM-32 Dev Module
1	×	Micro USB Cable
1	×	LCD I2C
1	×	Temperature and Humidity Sensor DHT11
Or 1	×	Temperature and Humidity Sensor DHT22
n	×	Jumper Wires

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About DHT11, DHT22 and LCD

If you do not have knowledge of DHT11, DHT22 temperature sensor and LCD (pinout, how they work, how to connect them to ESP32, how to program for them...), learn about them in the following tutorials:

Wiring Diagram

ESP32 - DHT11 Module Wiring

Image is developed using Fritzing. Click to enlarge image

ESP32 - DHT22 Module Wiring

ESP32 DHT22 temperature and humidity LCD Wiring Diagram

Image is developed using Fritzing. Click to enlarge image

ESP32 Code - DHT11 Sensor - LCD I2C

/* * Created by esp32io.com * * This example code is in the public domain * * Tutorial page: https://esp32io.com/tutorials/esp32-temperature-humidity-sensor-lcd */ #include <LiquidCrystal_I2C.h> #include "DHT.h" #define DHTPIN 2 #define DHTTYPE DHT11 LiquidCrystal_I2C lcd(0x3F, 16, 2); // I2C address 0x3F, 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("%"); } }

Quick Steps

If this is the first time you use ESP32, see how to setup environment for ESP32 on Arduino IDE
Connect the ESP32 board to your PC via a micro USB cable
Open Arduino IDE, select the right ESP32 board and COM port
On Arduino IDE, Go to Tools Manage Libraries

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 paste it to Arduino IDE
Click Upload button on Arduino IDE to compile and upload code to ESP32 board
Make enviroment around sensor hotter or colder
See the result in LCD

If LCD displays nothing, see Troubleshooting on LCD I2C

ESP32 Code - DHT22 Sensor - LCD I2C

/* * Created by esp32io.com * * This example code is in the public domain * * Tutorial page: https://esp32io.com/tutorials/esp32-temperature-humidity-sensor-lcd */ #include <LiquidCrystal_I2C.h> #include "DHT.h" #define DHTPIN 2 #define DHTTYPE DHT22 LiquidCrystal_I2C lcd(0x3F, 16, 2); // I2C address 0x3F, 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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