ESP32 - Temperature Sensor - LCD

This tutorial instructs you how to use ESP32 to read the temperature from DS18B20 temperature sensor and display it on LCD I2C 16x2.

Hardware Used In This Tutorial

1×ESP-WROOM-32 Dev Module
1×Micro USB Cable
1×LCD I2C
1×Temperature Sensor DS18B20
1×4.7 kΩ resistor
1×Breadboard
n×Jumper Wires
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Introduction to Temperature Sensor and LCD

We have specific tutorials about 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

wiring diagram between esp32 temperature sensor lcd

This image is created using Fritzing. Click to enlarge image

ESP32 Code

/* * 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-sensor-lcd */ #include <OneWire.h> #include <DallasTemperature.h> #include <LiquidCrystal_I2C.h> #define SENSOR_PIN 23 // ESP32 pin GIOP23 connected to DS18B20 sensor's DQ pin OneWire oneWire(SENSOR_PIN); DallasTemperature DS18B20(&oneWire); LiquidCrystal_I2C lcd(0x3F, 16, 2); // I2C address 0x27, 16 column and 2 rows float tempC; // temperature in Celsius float tempF; // temperature in Fahrenheit void setup() { DS18B20.begin(); // initialize the sensor lcd.init(); // initialize the lcd lcd.backlight(); // open the backlight } void loop() { DS18B20.requestTemperatures(); // send the command to get temperatures tempC = DS18B20.getTempCByIndex(0); // read temperature in Celsius tempF = tempC * 9 / 5 + 32; // convert Celsius to Fahrenheit lcd.clear(); lcd.setCursor(0, 0); // display position lcd.print(tempC); // display the temperature in Celsius lcd.print((char)223); // display ° character lcd.print("C"); lcd.setCursor(0, 1); // display position lcd.print(tempF); // display the temperature in Fahrenheit lcd.print((char)223); // display ° character lcd.print("F"); delay(500); }

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 “OneWire” on the search box, then look for the OneWire library by Paul Stoffregen
  • Click Install button to install OneWire library.
  • ESP32 onewire library
  • Type “Dallas” on the search box, then look for the DallasTemperature library by Miles Burton.
  • Click Install button to install DallasTemperature library.
  • ESP32 Dallas Temperature 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
  • Arduino IDE Upload Code
  • Make the sensor hotter or colder by gripping the DS18B20 temerature sensor on your hand, or embedding it on hot and cold water.
  • See the result in LCD

If the LCD displays nothing, see Troubleshooting on LCD I2C

Line-by-line Code Explanation

The above ESP32 code contains line-by-line explanation. Please read the comments in the code!

Video Tutorial

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