ArdCalc - Arduino Calculator

Simple calculator with four basic operations based on Arduino Uno.

What you need to make it?

• Arduino board (ATmega328)


• LCD Screen (compatible with Hitachi HD44780 driver)
• 10k ohm potentiometer
• 220 ohm resistor


• PCF8574 expander


• 15x pushbuttons
• 7x 10K ohm resistors

Wiring

How it works?

In the beginning we see „Arduino Calculator”. To start typing the first number, press „OK”.
After typing the number, choose one of the four basic operations mentioned below:

• ` + ` - addition
• ` - ` - subtraction
• ` * ` - multiplication
• ` / ` - division

After typing the second number, press „OK” to show the result.
If you want to reset the calculator, press "OK" again.

In order for ArdCalc to work correctly, I had to add some limitations:

1. If one of the numbers entered is greater than 999999, you will see "error” on the display.
   
2. If you try to divide by zero, you will see „inf” ( „infinity” ) on the display.