Adventures in Science: Arduino Literals, Variables and Data Types

Previously on “Adventures in Science,” I covered Arduino programming syntax. Now, we take a look at how to store numbers and characters in “containers” known as variables and how to access that data.

Before digging into literals and variables, we have to understand data types. A data type is a classification of information that tells the compiler how the programmer intends to use the information. In C, there are only three fundamental data types: integer (int), floating point (float) and character (char). However, you will also sometimes see void to indicate “nothing” or “no type.”

Arduino supports more data types, such as long int, which is an integer stored in 4 bytes, and unsigned int to mean an integer that’s only positive or 0.

Literals are fixed values that do not change throughout the program. For example, if you write the number 13 or 500 in your program, that’s a literal. Literals for characters can be expressed between single quotes as any ASCII-encoded character, such as 'g'.

Variables work like containers with labels. You can store information with the specified data type in a variable and then refer to the label later in the code when you need to retrieve or change the data. This can be extremely handy for manipulating data later in the code (with, for example, arithmetic operators) or setting a constant value once in the code (e.g., setting led = 13; and then using led instead of writing 13 several times).

Like your tutorials in written form? Here are a couple of guides that go over the basics of data types in Arduino and the American Standard Code for Information Interchange (ASCII):

Data Types in Arduino

Learn about the common data types and what they signify in the Arduino programming environment.


A brief history of how ASCII came to be, how it's useful to computers, and some helpful tables to convert numbers to characters.

Question for all you programmer types out there: Which do you prefer — strongly typed languages or weakly typed languages? Why? Please respond in the comments below.

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