How to make a giant calculator using arduino ! {Part 1}

{Sorry guys , its been long {SERIOUSLY LONG} time since my last post but I was working on a very big {and hectic } project for school submission so…}

This would be a two part post . In the first part i will explain the idea and hardware used and in second part i will talk about the actual build –   wiring ,  CODE and the schematics.



The main objective of this project was to understand the working of a simple digital calculator and to recreate it . The projects uses a 16*2 LCD display to display numbers , operators and the result and for the buttons it uses home made buttons made from scrap aluminium foil , sponges and wires **.

Here’s a short video i made describing the basic working of this build.

Credits { Team mates } :

So lets get started !


Materials Required :

  1. Arduino Board { Any of the board could work ; I used MEGA here }arduino-logo
  2. Lots of wire {Really a lots of  it }
  3. Aluminium foil , sponges and wires**
  4. 16*2 I2c Lcd Display {It has to be the I2c One !}


    16*2 LCD Display

  5. Cardboard or wood
  6. Glue Gun
  7. Soldering Iron
  8. Male headers {Optional}


    Male Headers

  9. Electrical Tape
  10. Cardboard/ MDF board / Wooden board

**{Or you could simply use 16 push buttons instead of making your own 🙂 }


Procedure :

Hardware :

Making The Buttons (You can skip this part If you want to use tactile push buttons instead)

We wanted to make a calculator purely from scratch so we made our own buttons . This idea of making buttons was proposed by Ashutosh so shout out to him .

  1. Cut 2 small square pieces of aluminium foil nearly 5 * 5 Cm in size .IMG_0047
  2. Take a sponge and divide it into square of 7*7 cm in size to get a small piece like this:IMG_0048
  3. Make small hole in the center of the sponge piece .
  4. Use tape or hot glue to stick a piece of aluminium foil to each side of sponge  .
  5. Glue wires with exposed ends to the foil pieces and make sure the bare ends of the wires are touching the foil .
  6. Now you have finally created a button . Use a continuity meter to check if the button is working fine .


    Final Button

  7. Repeat this 16 more times to get a total of 16 buttons .

And Now the most hectic part of the build {apart from coding } is complete .

Note : If using tactile buttons extend its two wires and cover the button with sponge or any other cushion type material.

Making the Base/Keypad .

  1. To make the base you can use  cardboard/ MDF board / Wood  sheet and cut it into a square of 1.5 m In size .
  2. Now ,take your buttons and lay them on the board equidistant from each other like this :


    Top :The display portion consisting of a wooden block (Un-drilled) ; Bottom : The main keypad structure with buttons

And that’s all for the hardware build .


The next part will be explaining the electronics ; schematics ; wiring and the coding stuff so stay tuned ! 🙂

project video :