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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
This image is created using Fritzing. Click to enlarge image
ESP32 - DHT22 Module Wiring
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);
}
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
- Type “DHT” on the search box, then look for the DHT sensor library by Adafruit
- Install the library by clicking on Install button.
- A windows appears to ask you to install dependencies for the library
- Install all dependencies for the library by clicking on Install All button.
- 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.
- 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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