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

April 17, 2021

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.

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

rsz_parts

For this project you’ll need the following parts:

You can use the preceding links or go directly to ehub247.com.ng/tools to find all the parts for your projects at the best price!

Schematics

Wire all the parts by following the next schematic diagram.

schematics_lcd_bb

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

lcd_pinout_print_screen

Code

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:
 https://randomnerdtutorials.com/
 
 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] = {
  B11111,
  B11111,
  B11111,
  B11111,
  B11111,
  B11111,
  B11111,
};

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
  lcd.clear();
  // Print a message to the LCD
  lcd.print(" LED Brightness");
  //set the cursor to line number 2
  lcd.setCursor(0,1);
  // 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);   
    lcd.write(byte(0));  
  }
  // delays 750 ms
  delay(750);        
}

View raw code

Demonstration

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.

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