Arduino Math and Logic Operations

From robotics

This page explains the different types of math and logic possible on an Arduino.

Arithmetic

These are the basic math commands for arduinos and most other hardware and software.

Examples
int result = 7 + 5; // result assigned to value 12
int result = 7 * 5; // result assigned to value 35
int result = 7 % 5; // result assigned to value 2

Comparison operators

These are the basic logic or comparison operators for arduinos and most other hardware and software. If the relationship that they check for is true, they return a 1. Otherwise they will return a 0.

Examples
boolean result = 5<10; // result will be equal to true
boolean result = 10<5; // result will be equal to false

Boolean operators

These are the basic boolean operators, often also referred to as logic gates.

  • && stands for an and gate. Using this operator, the resulting truth table is as follows:
Input A Input B Output
false false false
false true false
true false false
true true true


  • || stands for an "or" gate. Using this operator, the response table is as follows:
Input A Input B Output
false false false
false true true
true false true
true true true


  • ! stands for a not gate. Using this operator, the response table is as follows:
Input Output
0 1
1 0

Arduino variable types

Type Explanation Memory Size on Arduino Range signed Range unsigned
char Character. Smallest unit that can define a character 8 bit byte -128 to 127 0 to 255
byte Stores an 8 bit value 8 bit byte 0-255
boolean Stores a true or false value 1 bit 0 or 1
int Primary data type 2-8 bit bytes -32,768 to 32,767. 0 to 65,535
short Same as int 2-8 bit bytes -32,768 to 32,767
long Extended variable for number storage 4- 8 bit bytes -2,147,483,648 to 2,147,483,647 0 to 4,294,967,295
float Unit for handeling decimals. Rounds to 6 decimals. 4- 8 bit bytes 3.4028235E+38 to -3.3028235E+38
double That is, the double implementation is exactly the same as the float 4- 8 bit bytes 3.4028235E+38 to -3.3028235E+38
char[] (C-string) An array of characters Varies Limited by memory size
String (object) String class allows you to do more complex task at the cost of memory Varies Limited by memory size
array A collection of variables that can be saved and edited by accessing its index number Varies Limited by memory size

Math functions

min(x,y) // returns value of smaller number

max(x,y) // returns value of larger number

abs(x) // absolute value of the value entered

constrain(x , low , hi) // constrains first parameter by the following two parameters.

map(value, from low, from high, to low, to high) // linearly maps a value from one range to another

pow(base,exponent) // raises base to exponent

sqrt() // square root of value entered

sq() // squares the value entered

random(min,max) // returns a random integer in the range [min,max)

Trigonometry

sin(x) // returns the sin of an angle entered in radians

cos(x) // returns the cos of an angle entered in radians

tan(x) // returns the tam of an angle entered in radians

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