Calculator with Keypad and I2C LCD

https://youtu.be/_LWOT_el8vs

Pada hari ini (Senin, 1 April 2019) kami diberikan tugas untuk merancang calculator dengan menggunakan Arduino. Calculator ini dapat melakukan kalkulasi sederhana seperti tambah, kurang, kali, bagi, dan juga modulo. Pada saat keypad ditekan, buzzer akan menyala untuk menandakan tombol telah ditekan.

Kami menggunakan Arduino Uno sebagai microcontroller. Karena adanya keterbatasan PIN pada arduino UNO, kami akhirnya memutuskan untuk menggunakan I2C untuk mengefisiensikan PORT yang tersedia.

Alat dan Bahan

• Arduino Uno
• Jumper
• LCD
• I2C
• Buzzer
• Breadboard
• 4×4 keypad

Dokumentasi

Source Code

/*References:
* https://circuitdigest.com/microcontroller-projects/arduino-calculator-using-4×4-keypad
* https://medium.com/@18214030_IMKA/tugas-4-kalkulator-sederhana-6dc775f9811c
* https://www.sunfounder.com/learn/Sensor-Kit-v2-0-for-Arduino/lesson-1-display-by-i2c-lcd1602\
* -sensor-kit-v2-0-for-arduino.html
* https://bitbucket.org/fmalpartida/new-liquidcrystal/wiki/Home
*/

#include <Key.h>
#include <Keypad.h>
#include <Wire.h>
#include <hd44780.h> // main hd44780 header
#include <hd44780ioClass/hd44780_I2Cexp.h> // i2c expander i/o class header

//LCD I2C Initialization
hd44780_I2Cexp lcd; // declare lcd object: auto locate & config exapander chip
// LCD geometry
const int LCD_COLS = 16;
const int LCD_ROWS = 2;
int buzz = A3;

double num1,num2 ;
double total;
char operation,button;
const byte ROWS = 4; // Four rows
const byte COLS = 4; // Three columns

// Define the Keymap
char keys[ROWS][COLS] = {
{‘1′,’2′,’3′,’+’},
{‘4′,’5′,’6′,’-‘},
{‘7′,’8′,’9′,’*’},
{‘=’,’0′,’%’,’/’}
};
byte rowPins[ROWS] = { 9, 8, 7, 6 };// Connect keypad ROW0, ROW1, ROW2 and ROW3 to these Arduino pins.
byte colPins[COLS] = { 5, 4, 3, 2 }; // Connect keypad COL0, COL1 and COL2 to these Arduino pins.

Keypad kpd = Keypad( makeKeymap(keys), rowPins, colPins, ROWS, COLS ); // Create the Keypad

void domath() // Simple switch case to pick what operation to do, based on button pressed by user.
{
switch(operation)
{
case ‘+’: // Addition
total = num1+num2;
break;
case ‘-‘: // Subtraction
total = num1-num2;
break;
case ‘/’: // Division.
total = num1/num2;
break;
case ‘*’: // Multiplication
total = num1*num2;
break;
case ‘%’: // Modulus
total = (int)num1%(int)num2;
break;
}
// Based on case selected print our total and
lcd.setCursor(0,1);
lcd.print(‘=’);
lcd.setCursor(1,1);
lcd.print(total);
}

void setup() {
int status;

// initialize LCD with number of columns and rows:
// hd44780 returns a status from begin() that can be used to determine if initalization failed.
status = lcd.begin(LCD_COLS, LCD_ROWS);
if(status) // non zero status means it was unsuccesful
{
status = -status; // convert negative status value to positive number

// begin() failed so blink error code using the onboard LED if possible
hd44780::fatalError(status); // does not return
}

// initalization was successful, the backlight should be on now

// Print a message to the LCD
lcd.print(“Calculator”);

pinMode(buzz, OUTPUT);
}

void loop()
{
// Loops are convenient for reading key press from keypad
while(1) // First loop. Composing first number. Until operator pressed
{
button = kpd.getKey(); // Button read
if (button >=’0′ && button <=’9′) // If user pressed numeric value, 1 character at a time.
{
toneButton(button);
lcd.clear();
num1 = num1*10 + (button -‘0′); //First operand composing
lcd.setCursor(0,0); // Select first row on lcd
lcd.print(num1); // Print current number1
}

//Inputting operator
if (num1 !=0 && (button==’+’ || button==’-‘ || button==’*’ || button==’/’ || button==’%’))
{
toneButton(button);
operation = button; // operation remembers what mathematical operation user wants on numbers
lcd.setCursor(0,1); // set cursor to row 2
lcd.print(operation); // print our operator
break;
}
}

while(1) // Second loop. Inputting second operand. Until ‘=’ pressed
{
button = kpd.getKey(); // Button read
if (button >=’0′ && button <=’9′) // Getting chars from keypad for second number
{
toneButton(button);
num2 = num2*10 + (button -‘0’); //Second operand composing
lcd.setCursor(1,1); // Select second row, second column on lcd
lcd.print(num2); // Print current operand2
}

if (button == ‘=’ && num2 !=0) //Do calculation if ‘=’ is pressed
{
toneButton(‘=’);
domath(); //Calls domath() subroutine
break;
}
}

while(1) // Clearing screen for next calculation
{
//Waits ‘=’ key to be pressed so it can reset program and start over.
button = kpd.getKey();
if (button ==’=’)
{
toneButton(‘=’);
lcd.clear();
lcd.setCursor(0,0);
num1=0;
num2=0;
total=0;
operation=0;
break;
}
}
}

void toneButton(char key){
switch(key) {
case ‘1’:
tone(buzz, 262, 250);
break;
case ‘2’:
tone(buzz, 294, 250);
break;
case ‘3’:
tone(buzz, 330, 250);
break;
case ‘4’:
tone(buzz, 349, 250);
break;
case ‘5’:
tone(buzz, 392, 250);
break;
case ‘6’:
tone(buzz, 440, 250);
break;
case ‘7’:
tone(buzz, 494, 250);
break;
case ‘8’:
tone(buzz, 523, 250);
break;
case ‘9’:
tone(buzz, 587, 250);
break;
case ‘+’:
tone(buzz, 659, 250);
break;
case ‘-‘:
tone(buzz, 698, 250);
break;
case ‘*’:
tone(buzz, 784, 250);
break;
case ‘/’:
tone(buzz, 880, 250);
break;
case ‘%’:
tone(buzz, 988, 250);
break;
case ‘=’:
tone(buzz, 1047, 100);
delay(10);
tone(buzz, 1047, 100);
break;
default:
break;
}
}