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	×	Jumper Wires
1	×	(Optional) 5V Power Adapter
1	×	(Optional) DC Power Jack
1	×	(Optional) ESP32 Screw Terminal Adapter

One of the following breadboard:

1	×	Full-sized 830-Point Breadboard
1	×	Half-sized 400-point Breadboard
1	×	Mini-sized 170-point Breadboard
1	×	All-sized Breadboard Kit

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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

This image is created using Fritzing. Click to enlarge image

For ease of connection, it's advisable to purchase a DS18B20 sensor that comes with a wiring adapter equipped with a built-in resistor, eliminating the need for an additional resistor in the wiring.

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); }

※ 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

Type “OneWire” on the search box, then look for the OneWire library by Paul Stoffregen
Click Install button to install OneWire library.

Type “Dallas” on the search box, then look for the DallasTemperature library by Miles Burton.
Click Install button to install DallasTemperature 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.

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 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!

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