TASK 1
SIMPLE CALCULATOR
COMPONENTS USED
Keypad 4*4
potentiometer
resistor
Breadboard small
Arduino input
Arduino input
simple calculator code
#include <LiquidCrystal.h>
#include <Keypad.h>
LiquidCrystal lcd(13, 12, 11, 10, 9, 8);
long first = 0;
long second = 0;
double total = 0;
int posit = 0 ;
char customKey;
const byte ROWS = 4;
const byte COLS = 4;
char keys[ROWS][COLS] = {
{'1','2','3','/'},
{'4','5','6','*'},
{'7','8','9','-'},
{'C','0','=','+'} };
byte rowPins[ROWS] = {7 ,6 ,5 ,4};
byte colPins[COLS] = {3, 2, 1, 0};
Keypad customKeypad = Keypad( makeKeymap(keys), rowPins, colPins, ROWS, COLS);
void setup(){
lcd.begin(16,2);
lcd.setCursor(5,0);
lcd.clear(); }
void loop() {
customKey = customKeypad.getKey();
switch(customKey) {
case '0' ... '9':
lcd.setCursor(0,0);
first = first * 10 + (customKey - '0');
lcd.print(first);
posit++;
break;
case '+':
first = (total != 0 ? total : first);
lcd.setCursor(posit,0);
lcd.print("+");
posit++;
second = SecondNumber();
total = first + second;
lcd.setCursor(1,1);
lcd.print(total);
first = 0,
second = 0;
posit=0;
break;
case '-':
first = (total != 0 ? total : first);
lcd.setCursor(posit,0);
lcd.print("-");
posit++;
second = SecondNumber();
total = first - second;
lcd.setCursor(1,1);
lcd.print(total);
first = 0,
first = 0,
second = 0;
posit=0;
break;
case '*':
first = (total != 0 ? total : first);
lcd.setCursor(posit,0);
lcd.print("*");
posit++;
second = SecondNumber();
total = first * second;
lcd.setCursor(1,1);
lcd.print(total);
first = 0,
second = 0;
posit=0;
break;
case '/':
first = (total != 0 ? total : first);
lcd.setCursor(posit,0);
lcd.print("/");
posit++;
second = SecondNumber(); lcd.setCursor(1,1);
second == 0 ? lcd.print("Error") : total = (float)first / (float)second;
lcd.print(total);