Arduino Nano ESP32 - DHT22 - LCD

This tutorial instructs you how to program Arduino Nano ESP32 to read temperature and humidity from DHT22 and display them on LCD I2C.

Hardware Preparation

1	×	Arduino Nano ESP32
1	×	USB Cable Type-C
1	×	LCD I2C 16x2
1	×	DHT22 Temperature and Humidity Sensor
1	×	Breadboard
1	×	Jumper Wires
1	×	(Optional) DC Power Jack
1	×	(Recommended) Screw Terminal Expansion Board for Arduino Nano
1	×	(Recommended) Breakout Expansion Board for Arduino Nano

Or you can buy the following sensor kits:

1	×	DIYables Sensor Kit (30 sensors/displays)
1	×	DIYables Sensor Kit (18 sensors/displays)

Disclosure: Some of the links provided in this section are Amazon affiliate links. We may receive a commission for any purchases made through these links at no additional cost to you.
Additionally, some of these links are for products from our own brand, DIYables.

Overview of DHT22 and LCD

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

Wiring Diagram

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Arduino Nano ESP32 Code - DHT22 Sensor - LCD I2C

/* * This Arduino Nano ESP32 code was developed by newbiely.com * * This Arduino Nano ESP32 code is made available for public use without any restriction * * For comprehensive instructions and wiring diagrams, please visit: * https://newbiely.com/tutorials/arduino-nano-esp32/arduino-nano-esp32-dht22-lcd */ #include <DHT.h> #include <LiquidCrystal_I2C.h> #define DHT22_PIN D2 // The Arduino Nano ESP32 pin connected to DHT22 sensor LiquidCrystal_I2C lcd(0x27, 16, 2); // I2C address 0x27 (from DIYables LCD), 16 column and 2 rows DHT dht22(DHT22_PIN, DHT22); void setup() { dht22.begin(); // initialize the DHT22 sensor lcd.init(); // initialize the lcd lcd.backlight(); // open the backlight } void loop() { float humidity = dht22.readHumidity(); // read humidity float temperature = dht22.readTemperature(); // read temperature lcd.clear(); // check whether the reading is successful or not if (isnan(temperature) || isnan(humidity)) { lcd.setCursor(0, 0); lcd.print("Failed"); } else { lcd.setCursor(0, 0); // display position lcd.print("Temp: "); lcd.print(temperature); // display the temperature lcd.print("°C"); lcd.setCursor(0, 1); // display position lcd.print("Humi: "); lcd.print(humidity); // 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

Detailed Instructions

To get started with Arduino Nano ESP32, follow these steps:

If you are new to Arduino Nano ESP32, refer to the tutorial on how to set up the environment for Arduino Nano ESP32 in the Arduino IDE.
Wire the components according to the provided diagram.
Connect the Arduino Nano ESP32 board to your computer using a USB cable.
Launch the Arduino IDE on your computer.
Select the Arduino Nano ESP32 board and its corresponding COM port.* Click to the Libraries icon on the left bar of the Arduino IDE.
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.

Arduino Nano 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.

Arduino Nano ESP32 LiquidCrystal I2C library

Copy the above code and paste it to Arduino IDE.
Compile and upload code to Arduino Nano 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

Video Tutorial

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