Arduino Nano - Ultrasonic Sensor - LCD

This tutorial instructs you how to use Arduino Nano to obtain the distance from an ultrasonic sensor and show it on an LCD I2C display.

Hardware Preparation

1×Arduino Nano
1×USB A to Mini-B USB cable
1×Ultrasonic Sensor
1×Jumper Wires
1×(Optional) 9V Power Adapter for Arduino Nano
1×(Recommended) Screw Terminal Adapter 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)
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Overview of Ultrasonic Sensor and LCD

If you are unfamiliar with Ultrasonic sensor and LCD (including pinout, how it works, and how to program), the following tutorials can help you:

Wiring Diagram

The wiring diagram between Arduino Nano and Ultrasonic Sensor LCD

This image is created using Fritzing. Click to enlarge image

Arduino Nano Code

/* * This Arduino Nano code was developed by * * This Arduino Nano code is made available for public use without any restriction * * For comprehensive instructions and wiring diagrams, please visit: * */ #include <LiquidCrystal_I2C.h> #define TRIG_PIN 4 // The Arduino Nano pin connected to TRIG pin of ultrasonic sensor #define ECHO_PIN 3 // The Arduino Nano pin connected to ECHO pin of ultrasonic sensor LiquidCrystal_I2C lcd(0x27, 16, 2); // I2C address 0x27 (from DIYables LCD), 16 column and 2 rows float duration_us, distance_cm; void setup() { lcd.init(); // Initialize the LCD I2C display lcd.backlight(); // open the backlight pinMode(TRIG_PIN, OUTPUT); // config trigger pin to output mode pinMode(ECHO_PIN, INPUT); // config echo pin to input mode } void loop() { // Produce a 10-microsecond pulse to the TRIG pin. digitalWrite(TRIG_PIN, HIGH); delayMicroseconds(10); digitalWrite(TRIG_PIN, LOW); // Measure the pulse duration from the ECHO pin duration_us = pulseIn(ECHO_PIN, HIGH); // calculate the distance distance_cm = 0.017 * duration_us; lcd.clear(); lcd.setCursor(0, 0); // start to print at the first row lcd.print("Distance: "); lcd.print(distance_cm); delay(500); }


The I2C address of LCD can differ depending on the manufacturer. In our code, we used 0x27 which was specified by DIYables manufacturer.

Detailed Instructions

  • Connect your Arduino Nano to your computer using a USB cable.
  • Launch the Arduino IDE and select the appropriate board and port.
  • Click to the Libraries icon on the left bar of the Arduino IDE.
  • Search for “LiquidCrystal I2C”, and locate the LiquidCrystal_I2C library created by Frank de Brabander.
  • Then, click the Install button to install the library.
Arduino Nano LiquidCrystal I2C library
  • Copy the code and open it with the Arduino IDE.
  • Then, press the Upload button on the Arduino IDE to compile and upload the code to the Arduino Nano.
Arduino IDE Upload Code
  • Attach the sensor to both hot and cold water, or hold it in your hand.
  • Then, observe the outcome displayed on the LCD.

Code Explanation

Check out the line-by-line explanation contained in the comments of the source code!


  • If the LCD screen is not displaying anything, please refer to Troubleshooting on LCD I2C for help.
  • The code provided above is for educational purposes only. The ultrasonic sensor is very sensitive to noise, so if you want to use it in a real-world application, you should filter out the noise. For more information on how to do this, please refer to how to filter noise for ultrasonic sensor.

Video Tutorial


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