Project tutorial
Simple UNO calculator

Simple UNO calculator © GPL3+

Make simple math with arduino UNO

  • 26 respects

Components and supplies

Ph a000066 iso (1) ztbmubhmho
Arduino UNO
Just the board will do it, no need for more. Also, if 'im not mistaken, this will work with any board, original or not. If it works with Arduino IDE, this project works on it.
Ph abx00005 iso (1) bavevgguw1
Arduino 101
Ard nano
Arduino Nano R3
Ard yun
Arduino Yun
Ph a000067 iso (1) wzec989qrf
Arduino Mega 2560
Ard due
Arduino Due
A000057 featured
Arduino Leonardo

Apps and online services

About this project

One day, my math teacher asked me as I was talking about arduino : "Can you do math with it?".I replied "I don't know", and that got me thinking about how to make that happen. Then, I kinda figured it out how to do it and i wanna share now.

So here it is! A very simple way of doing math with arduino. For my project, I used arduino UNO, but I belive it works with any of them.

The step-by-step is very simple:

  • Connect the board with the computer
  • Upload the code below
  • Enable Serial monitor
  • Write a calculation that is valid (See the code for more instructions)

I plan to make a better calculator, but for now it's just that : a way of doing basic math. If you want the "better" calculator, please let me know.

Stay tuned to see a better "calculator"! Hope to see you soon!


You enter the numbers and the signal togheter, like "2+3", or 8*2, and it gives the result
/* Serial arduino calculator
in this project, you can make basic
arithmetic with the help of arduino,
almost like a very rustic calculator.
It accepts two numbers and a signal, and
makes the operation, witch can be of +, -, * or /.
E.G. : send "2+3" (Without quotes and with no
space separing the info), and arduino answers 5.
Digit "7-3" and arduino te responde com 4.
Criado por João Paulo Rodrigues Poltronieri

This code is on public domain

// first of all, create variables to store
// the information sent to arduino

lng number1; // first number of the calculation,
// sent through the Serial monitor

// If you take a look, it's a long varible, so
// we're able to use big numbers

long number2; // second number sent through the SM

char calSignal; // create a char variable to store
// the calcuation signal.

long result; // result of the calculation

void setup() {
  Serial.begin(9600); // begins serial communications
  Serial.println("Send me a calculation"); 
  Serial.println("E.G. : 2+3");
  // prints this to test serial communication, and
  // prints a line space

void loop() {
  while(Serial.available() > 0) {
    // while there are dada being sent to arduino,
    number1 = Serial.parseInt();
    // number1 will be the first number
    // Note the use of "Serial.parseInt, so,
    // in case you use 23, it stores in 
    // number1 the number 23
    // if we used, it would
    // only store 2
    calSignal =; // calSignal will be the first
    // info after the first number
    number2 = Serial.parseInt(); // stores the second
    // number in number2
    resolucao(); // Custom function to solve the calculations
    Serial.println("Resultado = ");
    // Prints the result of the calculation
    Serial.println(); // jumps a line
    Serial.println("Outra conta, por favor"); // prints
    Serial.println(); // jumps a line

void resolucao() { // Custom function that
  // solves the calculations
  switch (calSignal) {
    // Here we use "" to save some space on
    // the sketch. It's, basicaly, a function that verifies
    // various "if" statements.
    // Here, it verifies what's the value held by 
    // calSigna. Basicaly, it verifies the "signal"
    // of the calculation
    case '+' : // if calSignal is '+'
    result = number1 + number2; // sums the numbers
    // and makes result hold the value of the calculation
    break; // break to exit the "case"
    case '+' : // if calSignal is '+'
    result = number1 - number2; // subtracts the numbers
    // and makes result hold the value of the calculation
    break; // break to exit the "case"
    case '+' : // if calSignal is '+'
    result = number1 * number2; // multiplies the numbers
    // and makes result hold the value of the calculation
    break; // break to exit the "case"
    case '/' : // se calSignal for '/'
    result = number1 / number2; // divides the numbers
    // and makes result hold the value of the calculation
    // PS: in case the division isn't exact, the result 
    // will be the nearest integrer
    break; // break to exit the "case"
    default : // If it's not any of these...
    Serial.println("CONTA INVÁVIDA");
    // Creates an "error"
    resultado = 0;


What you need for it to work
Basicaly, just the board is needed, actually
Arduino uno aglrrm3hdm


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