SENSORS/ACTUATORS

Arduino Nano 33 IoT - DHT11 - LCD

This guide shows you how to use the Arduino Nano 33 IoT to measure temperature and humidity with a DHT11 sensor and display the numbers on an LCD using I2C.

Hardware Preparation

1	×	Arduino Nano 33 IoT
1	×	Micro USB Cable
1	×	LCD I2C 16x2
1	×	DHT11 Temperature and Humidity Sensor
1	×	Breadboard
1	×	Jumper Wires
1	×	Optionally, DC Power Jack
1	×	Recommended: Screw Terminal Expansion Board for Arduino Nano
1	×	Recommended: Breakout Expansion Board for Arduino Nano
1	×	Recommended: Power Splitter 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 DHT11 and LCD

If you're new to using the DHT11, LCD, and Arduino Nano 33 IoT, please check out these tutorials:

These tutorials explain how DHT11 and LCD work, their pinouts, how to connect them to the Arduino Nano 33 IoT, and how to program Arduino Nano 33 IoT to work with the DHT11 and LCD.

Wiring Diagram

This image is created using Fritzing. Click to enlarge image

Arduino Nano 33 IoT Code - DHT11 Sensor - LCD I2C

/* * This Arduino Nano 33 IoT code was developed by newbiely.com * * This Arduino Nano 33 IoT code is made available for public use without any restriction * * For comprehensive instructions and wiring diagrams, please visit: * https://newbiely.com/tutorials/arduino-nano-iot/arduino-nano-33-iot-dht11-lcd */ #include <DHT.h> #include <LiquidCrystal_I2C.h> #define DHT11_PIN 2 // The Arduino Nano 33 IoT pin connected to DHT11 sensor LiquidCrystal_I2C lcd(0x27, 16, 2); // I2C address 0x27 (from DIYables LCD), 16 column and 2 rows DHT dht11(DHT11_PIN, DHT11); void setup() { dht11.begin(); // initialize the DHT11 sensor lcd.init(); // initialize the lcd lcd.backlight(); // open the backlight } void loop() { float humidity = dht11.readHumidity(); // read humidity float temperature = dht11.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:

Different companies might use different LCD I2C addresses. In this code, we used the address 0x27 as provided by the DIYables company.

Detailed Instructions

If you are new to the Arduino Nano 33 IoT, be sure to check out our Getting Started with Arduino Nano 33 IoT tutorial. Then, follow these steps:

Connect the components to the Arduino Nano 33 IoT board as depicted in the diagram.
Use a USB cable to connect the Arduino Nano 33 IoT board to your computer.
Launch the Arduino IDE on your computer.
Select the Arduino Nano 33 IoT board and choose its corresponding COM port.
Click the Libraries icon on the left side of the Arduino program.
Type DHT in the search box and find the DHT sensor library by Adafruit.
Click the Install button to add the library.

A window will pop up asking you to set up the extra software for the library.
Click the Install All button to install all the extra software.

Arduino Nano 33 IoT Adafruit Unified sensor library

Type LiquidCrystal I2C in the search box, and then find the LiquidCrystal_I2C library by Frank de Brabander.
Click the Install button to add the LiquidCrystal_I2C library.

Arduino Nano 33 IoT LiquidCrystal I2C library

Copy the above code and paste it into the Arduino IDE.
Click the Upload button in the Arduino IDE to compile the code and send it to the Arduino Nano 33 IoT board.
Change the temperature that the sensor reads by making it colder or warmer. For example, place the sensor near a hot cup of coffee.
Watch the result on the LCD screen.

If your LCD screen stays blank, check the LCD I2C troubleshooting guide.

Video Tutorial

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