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  • Writer's picturePuriphico

data types and conversions: variables in arduino programming (part 2)

This article details the most common data types used in Arduino programming.

Data types:

  • Array

    • A collection of variables that can be accessed via an index number.

    • Below are the various methods of declaring arrays:


int myInts: declares an array without initializing it.

int myPins: declares an array without specifying size.

int mySensVals: declares an array and specifies size.

  • Bool

    • Can hold either a true or false value.

    • Syntax: bool var = val

      • Var refers to a variable.

      • Val is the value you assign to that variable.

  • Char

    • A data type used to store a character value.

    • Character literals, or just letters, are enclosed by single quotes, whereas a collection of characters, also known as a string, uses double quotes.

      • Examples:

        • char myLetter = 'A';

        • char myInitials = "AL";

  • Byte

    • Stores an eight bit integer number, from 0-255.

    • Syntax: byte var = val

      • 'var' and 'val' have the equivalent meaning as they do with respect to the bool data type.

  • Float

    • Data type for floating-point numbers, or numbers with decimal points.

    • Often used to approximate values as they have greater resolution (precision) than integers.

    • Syntax: float var = val

      • Example:

        • float pi = 3.14

    • Warnings:

      • Floating-point arithmetic takes longer to compute than it would if integers were used.

      • The float data type has 6-7 digits of precision (note: not digits after the decimal point, but total digits).

  • Int

    • Primary data type for number storage.

    • Syntax: int var = val

  • Void

    • Used only in function declarations (ie void loop, void setup)

    • Void Indicates that the following function is not expected to return any information to the function from which it was called.

      • For example, although there are actions performed within the void setup and void loop functions, no information is returned to the larger program.

Conversions - converting one data type to another:

  • byte(x) converts the value x into a byte data type

  • char(x) converts the value x into a char data type

  • float(x) converts the value x into a float data type

  • int(x) converts the value x into an int data type

  • etc

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