Arduino Data Types

Arduino Data Types
Arduino Data Types

We learned what a Arduino Data Types  variable is and how it stores information in the previous lesson. But we didn’t discuss what variables store? Data may be numeric, character, short, etc. So Data types are needed in programming. Data is just information, which can take any shape. So Data in programming refers to numbers, symbols, or other formats that most programming languages can handle. Thus, variables are told what data to store by data types. The Arduino data types may store numbers or perform mathematical operations, and the program appears friendly. However, the code can be used on multiple sizes and platforms, thus data types must be chosen carefully.

When you first start using Arduino, you may wonder why code examples use strange terminology like int, byte, and float. Learn about data types without fear! We’ll cover Arduino’s main data types in this simple guide. We’ll simplify integers, Booleans, and other data types so you know when to utilize them. After learning a few basics, you can declare variables and store sensor values quickly. Stay with us and you’ll progress from data type novice to Arduino guru in minutes!

What are data types?

A program’s data types define what data a variable can store. Each type of data is kept in working memory and moved in and out of the processor as code is performed. Early C programmers learn data types, one of the most crucial topics. This is because the data you utilize immediately affects your computations. If you use operations supported by one data type on another that doesn’t, you may encounter complications that take extensive searching to resolve. When declaring a new variable, you inform the computer “I’m going to need a bit of memory here to store a value” and “this is the type of data I’m going to be working with” by defining a data type.

Before writing new code, Arduino’s built-in variable types must be understood. You can also specify your own variable types and assign any bit pattern your application needs. Early C programmers learn data types, one of the most crucial topics. This is because the data you utilize immediately affects your computations. If you use operations supported by one data type on another that doesn’t, you may encounter complications that take extensive searching to resolve. By declaring a new variable with a data type, you’re telling the computer “I’m going to need a bit of memory here to store a value” and “this is the type of data I’m going to be working with”.

Data types matter in Arduino programming

Before using a variable in a drawing, data types declare its data type. Choosing the right data type in a sketch saves memory and speeds up execution. C, the Arduino language, has various variables. The most common Arduino ones will be covered here. The lack of unsigned variables and long long and double double data types will be noticeable to those coming from other programming languages. Saving memory and choosing the right variable type are essential for a successful sketch on the 2-byte MCU.

However, if a large value like 65000 needs to be stored in a variable, which is 2 bytes unsigned, we can use a 2 bytes int type because 65000 is supported in the range of an unsigned int (0 to 65535), saving memory. One reason to select the proper data type is that. Using the improper data type might cause overflow and unexpected effects. When a variable is defined, the compiler learns its value, memory allocation, and sign. DigitalRead expects a byte type parameter, regardless of the pin type, and byte types always have 1 byte and support 0 to 255 digital pin range. This limits parameter values and helps us find the right type.

Introduction to Arduino Data Types

Arduino requires knowledge of programming data types. These determine each variable’s memory allocation and value range.


Ints are whole numbers like -2, -1, 0, 1, 2, etc. The Arduino Uno’s 2 bytes of int memory may carry numbers from -32,768 to 32,767. Use int to store whole numbers in this range.Booleans represent true or false values. They take up 1 byte and are handy for tracking the state of anything, such a button’s press.

Characters can store letters, numerals, and symbols in 1 byte of memory. Use char to store one character. Single quotes like ‘A’ or ‘!’ enclose char values.Floats are decimal numbers, such as 3.14. They take up 4 bytes on an Arduino Uno and can store values from -3.4028235E+38 to 3.4028235E+38. For precision, store decimal numbers in float.Doubles, while decimal numbers, require 8 bytes of RAM for more precision. For memory savings on an Arduino Uno, use float instead of double.


Double quotations surround strings like “Hello!”. Their memory usage depends on string length. String stores text.Programming an Arduino requires data type knowledge. They efficiently store all kinds of data to fuel projects. Now you know the basics—use them in your sketches and you’ll learn them quickly!

Bytes, Ints, Unsigned Ints on Arduino

Arduino beginners must comprehend integer data types. Whole integers have no decimal point. Three main integer kinds are:


Bytes store 8-bit unsigned numbers from 0 to 255. Byte keyword. As an example: Five-byte b;

Integers (ints) store numbers from -32,768 to 32,767 in 16 bits. Use int. As an example: int i = -1000;

Unsigned Int

Unsigned 16-bit ints store only positive numbers from 0 to 65,535. Use unsigned int. As an example: unsigned int ui=5000;

Which type to use? That depends on the numbers you store. In general:

For little values 0-255, use byte to save memory. Int is best for general integer purposes. •Store only positive numbers in unsigned int.

Use the smallest size that fits your needs. This saves Arduino’s limited memory. Change to a larger type if needed.

Learn the essential integer data types to program Arduino creations. From here, you can study floats, characters, strings, and Boolean logic. Since Arduino is built on C/C++, many of its concepts will be recognizable to programmers.

Enjoy coding! Any Arduino data type questions? Let me know.

Arduino Double and Float Floating Points
The Arduino language uses float and double to store floating point integers. Non-integer numbers can be represented by floating point numbers, providing you more storage options.


Float can store 7-digit floating point numbers. Floats are ideal for fractional numbers when memory is constrained because they need 4 bytes. As an example:

123.45 float;

Scientific notation can express very big or very small float numbers:

f = 1.23e5; //123,000.


The double data type doubles float precision to 15 digits. Its 8 bytes of memory make it suitable for high accuracy and less memory constraint. As an example:

double 123.456789012345;

Doubles can be used in scientific notation:

1.23e50 double d;

Doubles help with calculations that compound slight errors over many processes. The greater precision prevents float type errors.

In conclusion, use float when you need fractional numbers but have limited memory, and double when precision and accuracy are crucial. Understanding Arduino floating point types lets you choose the proper type and construct more complicated Arduino projects.

Arduino Character and String Types

The Arduino language contains several character and text data types. These help show messages on LCD panels and send text over serial connections.


Char stores a single character like ‘A’ or ‘$’. It represents ASCII letters in 1 byte. Like this, you define char:

myChar = ‘x’;


String data types are suitable for long texts. A String can carry many characters, limited only by Arduino memory. Strings are defined this way:

MyString = “Hello”;

Strings require the String.h library at the top of your sketch:


String and char employ 128-character ASCII encoding. International text using Unicode letters need u8″string” syntax:

String unicodeString = “Héllò!”;

This encodes the string as UTF-8, which supports more characters.

Characters and strings give Arduino projects that interact with humans several options. You may display custom messages on LCDs, send serial text to a computer, or develop a simple user interface! You can support multilingual text with ASCII and Unicode.

Advanced Data: Arrays, Structs, Classes

After mastering basic data types, you can go on to more complicated alternatives that expand your Arduino project possibilities.


Arrays store numerous values of the same data type in one variable. An array can contain 5 numbers, 10 floats, or 20 characters. Declare an array with type, name, and size:
int myArray[5]; Creates a 5-integer array. Beginning at 0, you use an index to retrieve each array element:
Example: myArray[0] = 10; myArray[1] = 20; Arrays can contain any data type, such as floats, chars, or strings. Arrays simplify manipulating and iterating related values.

Each struct produces a new data type with numerous components of potentially distinct types. A struct could represent a person: struct Person { char name[50]; int age;};
This generates a Person type with a 50-character name array and an integer age field. Then create Person variables:
Person john; strcpy(“John Doe”); john.age = 30; You can logically group related data into structures.


Classes are advanced data and function encapsulators. They are the basis for C++ object-oriented programming (which Arduino uses). Classes let you design reusable software components that model real-world items.You can write complex, structured Arduino programs with arrays, structs, and classes. Have more questions? Let me know!


Here’s a quick overview of Arduino’s main data formats. Don’t worry about memorizing them now. Practice with int, float, and char types is crucial. Write more sophisticated programs and you’ll learn the others. The Arduino language is forgiving anyway. It warns you if you assign a value to the improper variable type. Reference this guide if you need a reminder. Get those data types down quickly with practice. Next, make your Arduino do some awesome stuff!

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