ESP32 - Temperature Humidity Sensor - LCD

This tutorial instructs you how to use ESP32 to read humidity and temperature value from DHT11/DHT22 sensors, and display on LCD I2C.

Hardware Used In This Tutorial

1×ESP-WROOM-32 Dev Module
1×Micro USB Cable
1×LCD I2C 16x2
1×DHT11 Temperature and Humidity Sensor
1×(Optional) DHT22 Temperature and Humidity Sensor
n×Jumper Wires
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Introduction to DHT11, DHT22 and LCD

We have specific tutorials about DHT11, DHT22 temperature sensor and LCD. Each tutorial contains detailed information and step-by-step instructions about hardware pinout, working principle, wiring connection to ESP32, ESP32 code... Learn more about them at the following links:

Wiring Diagram

ESP32 - DHT11 Module Wiring

wiring diagram between esp32 dht11 temperature and humidity lcd

This image is created using Fritzing. Click to enlarge image

ESP32 - DHT22 Module Wiring

wiring diagram between esp32 dht22 temperature and humidity lcd

This image is created using Fritzing. Click to enlarge image

ESP32 Code - DHT11 Sensor - LCD I2C

/* * This ESP32 code is created by esp32io.com * * This ESP32 code is released in the public domain * * For more detail (instruction and wiring diagram), visit https://esp32io.com/tutorials/esp32-temperature-humidity-sensor-lcd */ #include <DHT.h> #include <LiquidCrystal_I2C.h> #define DHT_SENSOR_PIN 23 // ESP32 pin GIOP23 connected to DHT11 sensor #define DHT_SENSOR_TYPE DHT11 LiquidCrystal_I2C lcd(0x3F, 16, 2); // I2C address 0x3F, 16 column and 2 rows DHT dht_sensor(DHT_SENSOR_PIN, DHT_SENSOR_TYPE); void setup() { dht_sensor.begin(); // initialize the DHT sensor lcd.init(); // initialize the lcd lcd.backlight(); // open the backlight } void loop() { float humi = dht_sensor.readHumidity(); // read humidity float tempC = dht_sensor.readTemperature(); // read temperature lcd.clear(); // check whether the reading is successful or not if (isnan(tempC) || isnan(humi)) { lcd.setCursor(0, 0); lcd.print("Failed"); } else { lcd.setCursor(0, 0); // display position lcd.print("Temp: "); lcd.print(tempC); // display the temperature lcd.print("°C"); lcd.setCursor(0, 1); // display position lcd.print("Humi: "); lcd.print(humi); // display the humidity lcd.print("%"); } // wait a 2 seconds between readings delay(2000); }

※ NOTE THAT:

The LCD I2C address can be different from each manufacturer. In the code, we used address of 0x27 that is specified by DIYables manufacturer

Quick Instructions

  • If this is the first time you use ESP32, see how to setup environment for ESP32 on Arduino IDE.
  • Do the wiring as above image.
  • Connect the ESP32 board to your PC via a micro USB cable
  • Open Arduino IDE on your PC.
  • Select the right ESP32 board (e.g. ESP32 Dev Module) and COM port.
  • On Arduino IDE, Navigate to Tools Manage Libraries
  • ESP32 add library
  • Type “DHT” on the search box, then look for the DHT sensor library by Adafruit
  • Install the library by clicking on Install button.
  • ESP32 DHT sensor library
  • A windows appears to ask you to install dependencies for the library
  • Install all dependencies for the library by clicking on Install All button.
  • ESP32 Adafruit Unified sensor library
  • Type “LiquidCrystal I2C” on the search box, then look for the LiquidCrystal_I2C library by Frank de Brabander
  • Click Install button to install LiquidCrystal_I2C library.
  • ESP32 LiquidCrystal I2C library
  • Copy the above code and paste it to Arduino IDE.
  • Compile and upload code to ESP32 board by clicking Upload button on Arduino IDE
  • Make the sensor colder or hotter. For example, putting the sensor near a hot cup of coffee
  • See the result in LCD

If LCD displays nothing, see Troubleshooting on LCD I2C

ESP32 Code - DHT22 Sensor - LCD I2C

/* * This ESP32 code is created by esp32io.com * * This ESP32 code is released in the public domain * * For more detail (instruction and wiring diagram), visit https://esp32io.com/tutorials/esp32-temperature-humidity-sensor-lcd */ #include <DHT.h> #include <LiquidCrystal_I2C.h> #define DHT_SENSOR_PIN 23 // ESP32 pin GIOP23 connected to DHT22 sensor #define DHT_SENSOR_TYPE DHT22 LiquidCrystal_I2C lcd(0x3F, 16, 2); // I2C address 0x3F, 16 column and 2 rows DHT dht_sensor(DHT_SENSOR_PIN, DHT_SENSOR_TYPE); void setup() { dht_sensor.begin(); // initialize the DHT sensor lcd.init(); // initialize the lcd lcd.backlight(); // open the backlight } void loop() { float humi = dht_sensor.readHumidity(); // read humidity float tempC = dht_sensor.readTemperature(); // read temperature lcd.clear(); // check whether the reading is successful or not if (isnan(tempC) || isnan(humi)) { lcd.setCursor(0, 0); lcd.print("Failed"); } else { lcd.setCursor(0, 0); // display position lcd.print("Temp: "); lcd.print(tempC); // display the temperature lcd.print("°C"); lcd.setCursor(0, 1); // display position lcd.print("Humi: "); lcd.print(humi); // display the humidity lcd.print("%"); } // wait a 2 seconds between readings delay(2000); }

Two above code has only one line different.

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