Arduino – Display the LED Brightness on a LCD 16×2

In this project we’re going to display the LED brightness on a LCD 16×2 with a progress bar. This is a good Arduino beginner project for getting started with the LCD display. We provide a list of the parts required, schematic diagram, and code.

Watch the video demonstration below

Introducing the LCD

The simplest and inexpensive way to display information is with an LCD (liquid crystal display). These are found in everyday electronics devices such as vending machines, calculators, parking meters, printers, and so on, and are ideal for displaying text or small icons. The figure below shows a 16×2 LCD front and the back view.

This LCD has 2 rows, and each row can display 16 characters. It also has LED backlight to adjust the contrast between the characters and the background.

When you buy a 16×2 LCD, usually it doesn’t come with breadboard friendly pins. So, you may need some headers.

Parts Required


For this project you’ll need the following parts:

You can use the preceding links or go directly to to find all the parts for your projects at the best price!


Wire all the parts by following the next schematic diagram.


The next table shows a brief description of each pin of the LCD display. Make sure your LCD uses the same pinout.



Copy the following code and upload it to your Arduino board. The code is well commented so that you can easily understand how it works, and modify it to include in your own projects.

 Created by Rui Santos
 All the resources for this project:
 Based on some Arduino code examples 

// include the library code
#include <LiquidCrystal.h>

// initialize the library with the numbers of the interface pins
LiquidCrystal lcd(12, 11, 5, 4, 3, 2);
int potPin = A0;       // Analog pin 0 for the LED brightness potentiometer
int ledPin = 6;        // LED Digital Pin with PWM
int potValue = 0;      // variable to store the value coming from the potentiometer
int brightness = 0;    // converts the potValue into a brightness 
int pBari = 0;         // progress bar
int i = 0;             // foor loop

//progress bar character for brightness
byte pBar[8] = {

void setup() {
  // setup our led as an OUTPUT
  pinMode(ledPin, OUTPUT); 
  // set up the LCD's number of columns and rows: 
  lcd.begin(16, 2);
  // Print a message to the LCD
  lcd.print(" LED Brightness");
  //Create the progress bar character
  lcd.createChar(0, pBar);

void loop() {
  // clears the LCD screen
  // Print a message to the LCD
  lcd.print(" LED Brightness");
  //set the cursor to line number 2
  // read the value from the potentiometer
  potValue = analogRead(potPin);        
  // turns the potValue into a brightness for the LED
  brightness=map(potValue, 0, 1024, 0, 255); 
  //lights up the LED according to the bightness
  analogWrite(ledPin, brightness); 
  // turns the brighness into a percentage for the bar 
  pBari=map(brightness, 0, 255, 0, 17);
  //prints the progress bar
  for (i=0; i < pBari; i++)
    lcd.setCursor(i, 1);   
  // delays 750 ms

View raw code


After uploading the code to your Arduino board, you can rotate the potentiometer to adjust the LED brightness and change the progress bar on the LCD.

For a complete demonstration watch the video at the beginning of the post.

Wrapping Up

This post showed you a basic example on how to use the LCD display with the Arduino. Now, the idea is to modify the sketch and use the display in other projects.

If you are a beginner to the Arduino, we recommend following our Arduino Mini Course that will help you quickly getting started with this amazing board.

If you like Arduino, you may also like:

Do you have any questions? Leave a comment down below!

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11 thoughts on “Arduino – Display the LED Brightness on a LCD 16×2”

  1. Hola Rui:
    En mi caso el código no corre, hay comandos en español, se debe cambiar al ingles.
    Por ejemplo … lcd . comenzará (16 , 2 )… ; debe decir LCD.begin(16,2) .
    He visto que muchos escriben en español y les funciona, porque? en el programa Arduino 1.0.5-r2, que utilizo, los sketch me acepta codificación de comandos en ingles.

  2. Hola Rui:
    Como se modificaría el sketch de modo que la visualiza la barra de progreso y su respectivo porcentaje de avanze ( 0 % ………100%).


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