Electronics Champ
Published © GPL3+

Decimal to Binary Converter using 4x4 Keypad

This project shows how to convert a Decimal number into a Binary number with Arduino Mega.

BeginnerShowcase (no instructions)4,130
Decimal to Binary Converter using 4x4 Keypad

Things used in this project

Hardware components

Arduino Mega 2560
Arduino Mega 2560
×1
4x4 Keypad
×1
OLED Display (I2C)
×1
LED (generic)
LED (generic)
×8
Breadboard (generic)
Breadboard (generic)
×1
Jumper wires (generic)
Jumper wires (generic)
×1

Software apps and online services

Arduino IDE
Arduino IDE

Story

Read more

Schematics

Schematic

Code

Code

Arduino
/*

  This sketch converts a Decimal number into a Binary number.
  The Decimal number is fed to the Arduino through a 4x4 Keypad.
  A function then converts this Decimal number to its Binary
  equivalent. These numbers are displayed on an OLED Display and Serial Monitor.
  The Binary number is also represented with 8 LEDs.

  This program is made by Shreyas for Electronics Champ YouTube Channel.
  Please subscribe to this channel. Thank You.

*/


//Including the libraries
#include <Keypad.h>
#include <Wire.h>
#include <Adafruit_GFX.h>
#include <Adafruit_SSD1306.h>

#define SCREEN_WIDTH 128
#define SCREEN_HEIGHT 64

const byte ROWS = 4; //Four rows of Keypad
const byte COLS = 4; //Four columns of Keypad
char key = "";
String decimalNum;
long decimalNumber;
long binaryNumber;
String stringBinary = "";

//Define the symbols on the buttons of the keypad
char Keys[ROWS][COLS] = {

  {'1', '2', '3', 'A'},
  {'4', '5', '6', 'B'},
  {'7', '8', '9', 'C'},
  {'*', '0', '#', 'D'}

};

byte rowPins[ROWS] = {2, 3, 4, 5};
byte colPins[COLS] = {6, 7, 8, 9};
Keypad myKeypad = Keypad(makeKeymap(Keys), rowPins, colPins, ROWS, COLS);
Adafruit_SSD1306 oled(SCREEN_WIDTH, SCREEN_HEIGHT);

//Prints the EChamp logo on OLED Display
static const uint8_t PROGMEM logo[] = {

  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  0x00, 0x00, 0x07, 0xe8, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  0x00, 0x00, 0xff, 0xff, 0xe0, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  0x00, 0x01, 0xff, 0xff, 0xf0, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  0x00, 0x07, 0xff, 0xff, 0xfc, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  0x00, 0x1f, 0xff, 0xff, 0xff, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  0x00, 0x7f, 0xff, 0xff, 0xff, 0xc0, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  0x00, 0xff, 0xff, 0xff, 0xff, 0xe0, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  0x01, 0xff, 0xff, 0xff, 0xff, 0xf0, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  0x03, 0xff, 0xff, 0xff, 0xff, 0xf8, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  0x07, 0xfc, 0x11, 0xf1, 0x0f, 0xfc, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x30, 0x00, 0x00,
  0x0f, 0xfc, 0xf1, 0xf1, 0xe7, 0xfe, 0x00, 0x7e, 0x60, 0x00, 0x30, 0x00, 0x00, 0x30, 0x00, 0x00,
  0x1f, 0xfd, 0xfb, 0xf3, 0xe7, 0xff, 0x00, 0x60, 0x60, 0x00, 0x30, 0x00, 0x00, 0x00, 0x00, 0x00,
  0x1f, 0xfd, 0xff, 0xff, 0xe7, 0xff, 0x00, 0x60, 0x63, 0x87, 0xbb, 0xc7, 0x1f, 0x33, 0xcf, 0x00,
  0x3f, 0xfd, 0xff, 0xff, 0xe7, 0xff, 0x80, 0x60, 0x66, 0xcd, 0xb3, 0x4d, 0x9b, 0x36, 0xdb, 0x00,
  0x3f, 0xfd, 0xf9, 0xf3, 0xe7, 0xff, 0x80, 0x7e, 0x64, 0x48, 0x33, 0x08, 0x99, 0x34, 0x18, 0x00,
  0x7e, 0x40, 0x11, 0xf1, 0x20, 0x1f, 0xc0, 0x60, 0x67, 0xc8, 0x33, 0x08, 0x99, 0x34, 0x1f, 0x00,
  0x7e, 0x7d, 0xf9, 0xf3, 0xe7, 0xdf, 0xc0, 0x60, 0x64, 0x08, 0x33, 0x08, 0x99, 0x34, 0x01, 0x00,
  0x7e, 0x7d, 0xfb, 0xff, 0xe7, 0xdf, 0xc0, 0x60, 0x66, 0xcd, 0xb3, 0x0d, 0x99, 0x36, 0xdb, 0x00,
  0x7e, 0x7d, 0xff, 0xff, 0xe7, 0xdf, 0xc0, 0x7e, 0x63, 0xc7, 0xbb, 0x07, 0x19, 0x33, 0xde, 0x00,
  0x7e, 0x7d, 0xf9, 0xf3, 0xe7, 0xdf, 0xe0, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  0xfe, 0x7c, 0xf1, 0xf1, 0x67, 0xdf, 0xe0, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  0xfe, 0x7e, 0x11, 0xf1, 0x0f, 0xdf, 0xe0, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  0xfe, 0x7f, 0xfb, 0xf3, 0xff, 0xdf, 0xe0, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  0xfe, 0x7f, 0xff, 0xff, 0xff, 0xdf, 0xe0, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  0xfe, 0x7f, 0xff, 0xff, 0xff, 0xdf, 0xe0, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  0xfe, 0x7f, 0xff, 0xff, 0xff, 0xdf, 0xe0, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  0xfe, 0x7f, 0xff, 0xff, 0xff, 0xdf, 0xe0, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  0xfe, 0x7f, 0xff, 0xff, 0xff, 0xdf, 0xe0, 0x3c, 0x60, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  0x7e, 0x7f, 0xff, 0xff, 0x7f, 0xdf, 0xe0, 0x7e, 0x60, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  0x7e, 0x7f, 0x27, 0xf8, 0x9f, 0xdf, 0xc0, 0x62, 0x7c, 0x71, 0xf7, 0x3e, 0x00, 0x00, 0x00, 0x00,
  0x7e, 0x7e, 0xf1, 0xe1, 0xcf, 0xdf, 0xc0, 0x60, 0x6c, 0x59, 0xbb, 0x36, 0x00, 0x00, 0x00, 0x00,
  0x7e, 0x7e, 0xf8, 0xe3, 0xef, 0xdf, 0xc0, 0x60, 0x64, 0x09, 0x91, 0x32, 0x00, 0x00, 0x00, 0x00,
  0x3e, 0x7c, 0xf9, 0xf3, 0xef, 0xdf, 0x80, 0x60, 0x64, 0xf9, 0x91, 0x32, 0x00, 0x00, 0x00, 0x00,
  0x3f, 0x01, 0xff, 0xff, 0xe0, 0x1f, 0x80, 0x62, 0x64, 0x89, 0x91, 0x32, 0x00, 0x00, 0x00, 0x00,
  0x1f, 0xfc, 0xf9, 0xf3, 0xef, 0xff, 0x80, 0x7e, 0x64, 0x99, 0x91, 0x36, 0x00, 0x00, 0x00, 0x00,
  0x1f, 0xfe, 0xf8, 0xe3, 0xef, 0xff, 0x00, 0x3c, 0x64, 0xf9, 0x91, 0x3e, 0x00, 0x00, 0x00, 0x00,
  0x0f, 0xfe, 0x71, 0xf1, 0xdf, 0xff, 0x00, 0x00, 0x00, 0x00, 0x00, 0x30, 0x00, 0x00, 0x00, 0x00,
  0x0f, 0xff, 0x01, 0xfc, 0x3f, 0xfe, 0x00, 0x00, 0x00, 0x00, 0x00, 0x30, 0x00, 0x00, 0x00, 0x00,
  0x07, 0xff, 0xff, 0xff, 0xff, 0xfc, 0x00, 0x00, 0x00, 0x00, 0x00, 0x20, 0x00, 0x00, 0x00, 0x00,
  0x03, 0xff, 0xff, 0xff, 0xff, 0xf8, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  0x01, 0xff, 0xff, 0xff, 0xff, 0xf0, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  0x00, 0xff, 0xff, 0xff, 0xff, 0xe0, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  0x00, 0x7f, 0xff, 0xff, 0xff, 0x80, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  0x00, 0x1f, 0xff, 0xff, 0xff, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  0x00, 0x07, 0xff, 0xff, 0xfc, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  0x00, 0x00, 0xff, 0xff, 0xe0, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  0x00, 0x00, 0x7f, 0xff, 0xc0, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  0x00, 0x00, 0x00, 0x40, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00

};

void setup() {

  Serial.begin(9600);
  oled.begin(SSD1306_SWITCHCAPVCC, 0x3C);
  oled.clearDisplay();

  //Prints the logo on OLED Display
  oled.drawBitmap(0, 0, logo, 128, 64, 1);
  oled.display();
  delay(3000);
  oled.clearDisplay();
  
  oled.setTextSize(2);
  oled.setTextColor(WHITE);
  oled.setCursor(5, 10);
  oled.print("D:");
  oled.println('0');
  oled.setTextSize(2);
  oled.setTextColor(WHITE);
  oled.setCursor(5, 40);
  oled.print("B:");
  oled.println('0');
  oled.display();

  //Sets pins 30 to 37 as output for LEDs
  for (int i = 30; i < 38; i++) {

    pinMode(i, OUTPUT);

  }

}

void loop() {

  key = myKeypad.getKey();

  if (key) {

    if (key != 'A' and key != 'B' and key != 'C' and key != 'D' and key != '*' and key != '#') {

      decimalNum = decimalNum + String(key);
      decimalNumber = decimalNum.toInt();

      if (decimalNumber <= 255) {

        //Converts Decimal to Binary
        binaryNumber = convertDecimalToBinary(decimalNumber);
        stringBinary = String(binaryNumber);

        //Prints the Binary and the Decimal numbers on the OLED Display
        oled.clearDisplay();
        oled.setTextSize(2);
        oled.setTextColor(WHITE);
        oled.setCursor(5, 10);
        oled.print("D:");
        oled.println(decimalNumber);
        oled.setTextSize(2);
        oled.setTextColor(WHITE);
        oled.setCursor(5, 40);
        oled.print("B:");
        oled.println(binaryNumber);
        oled.display();

        //Prints the Decimal number on the Serial Monitor
        Serial.print("Decimal: ");
        Serial.print(decimalNumber);
        Serial.print("      ");

        //Prints the Binary number on the Serial Monitor
        Serial.print("Binary: ");
        Serial.println(binaryNumber);

        //This function turns on the LEDs accordingly
        LEDOutput();

      }

      //If the decimal number is greater than 255...
      else {

        oled.clearDisplay();
        oled.setTextSize(2);
        oled.setTextColor(WHITE);
        oled.setCursor(5, 5);
        oled.print("Max value");
        oled.setCursor(5, 25);
        oled.print("allowed is");
        oled.setCursor(5, 45);
        oled.print("255");
        oled.display();
        Serial.println("Max value allowed is 255");
        delay(1000);

      }

    }

    //Clears the numbers
    else if (key == 'C') {

      decimalNum = "";
      decimalNumber = 0;
      oled.clearDisplay();
      oled.setTextSize(2);
      oled.setTextColor(WHITE);
      oled.setCursor(5, 10);
      oled.print("D:");
      oled.println('0');
      oled.setTextSize(2);
      oled.setTextColor(WHITE);
      oled.setCursor(5, 40);
      oled.print("B:");
      oled.println('0');
      oled.display();

      for (int i = 30; i < 38; i++) {

        digitalWrite(i, 0);

      }

    }

  }

}

//This function converts a Decimal number to Binary number
long convertDecimalToBinary(int number) {

  int reminder;
  String bin;

  while (number) {

    reminder = number % 2;
    number = number / 2;
    bin = String(reminder) + bin;

  }

  return bin.toInt();

}

//This function turns on the LEDs accordingly
void LEDOutput() {

  int led = 30;
  int eight_bitBinary;

  if (stringBinary.length() != 8) {

    eight_bitBinary = 8 - stringBinary.length();

    for (int i = 0; i < eight_bitBinary; i++) {

      stringBinary = "0" + stringBinary;

    }

  }

  for (int i = 0; i <= 8; i++) {

    int ledState = stringBinary.substring(i, i + 1).toInt();
    digitalWrite(led, ledState);
    led = led + 1;

  }

}

Credits

Electronics Champ

Electronics Champ

4 projects • 11 followers
Projects based on breadboard electronics and Arduino with clear step-by-step instructions, circuit diagrams, schematics, and source code.

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