Arduino Functions

Arduino Functions
Arduino Functions

Students constructing projects with the Arduino board frequently focus so much on programming and connecting circuits that they overlook the Arduino code libraries’ basic functionality. 13 separate functions? What are these mysterious functions? Aren’t they frequently writing hundreds of lines of code to turn a single LED on or off? An Arduino function is a standalone code unit that explains and executes a code action. In other words, you can’t reuse code after writing a function. You call it every time in code. This functionality greatly increases code efficiency and readability.

Overview of Arduino Functions

Libraries offer several Arduino functions you can use in your scripts. You can use the Arduino’s built-in library’s digitalWrite command to blink the LED without writing LED driver code. Setup and loop are the simplest programs. Setup starts once at program startup, then loop runs indefinitely. You can call your own functions from these programs to simplify the code. In the setup method, you can call the function once, or in the loop, to call it repeatedly. Send arguments to functions to generate as many intricate and different actions as you want.

Importance of Understanding Arduino Functions

However, if you understand the principles and use functions, you can easily write code to solve problems. Understanding every inch of Arduino functions, what arguments it needs, and what it will return or perform elliptical or my current responsibilities beyond maths, science, and technology into creativity, arts, communications, etc. is a comprehensive way to distinguish the average coder from the high-level engineer.

Common Terminology in Arduino Programming

A compiler transforms Arduino IDE code to a HEX file uploaded to the microcontroller. The IDE displays “Done compiling” followed by the code size and a successful completion message. Click the upload tab to upload your Arduino application. Arduino IDE automatically saves your software before uploading it to the Arduino board. Write debug lines in the message box of Arduino IDE when developing embedded C code to see where it’s working. The message bar can be used as printf in code, however it doesn’t contain the newline command, so use it elsewhere. In series, the LED isn’t as bright, and in parallel, the gadgets utilize a lot of current and can be damaged.

You just received your first Arduino and want to make cool projects. However, examples and tutorials show weird code with “void” and parenthesis. What are “functions” and how do you use them? Don’t fear these code blocks! Unlock programming’s power by understanding Arduino functions’ basic structure. We’ll explain functions, why they’re useful, and how to utilize and build built-in and custom functions. The right explanations and examples will turn you from functions phobic to functions devotee in no time. Connect your Arduino and start coding!

What Are Arduino Functions?

Functions let you organize code into executable chunks. They organize and modularize your program. Important Arduino functions:

  • A function is defined using void functionName() {…}. No value is returned by void.
  • Use parameters to give information to a function, such as void functionName(int x) {…} to pass the value of x.
  • Functions can return non-void data. FunctionName() yields the number 5.
  • Parentheses are used to call a function: functionName();
  • Functions can be defined above or below their call.

Some Arduino routines to create:

Turn on LED

Make the LED-turning code a function to reuse it: void turnOnLED() { digitalWrite(ledPin, HIGH);� Call turnOnLED() to turn on the LED.

Read Sensor

Put code in a function to read a sensor numerous times:
Int readSensor() { return sensorValue; } When you wish to read the sensor, call int value = readSensor().

Complex Logic

DRY code is kept in functions for sophisticated logic used several times. As an example: void checkIfOverThreshold(int threshold) { if (readSensor() > threshold) { turnOnLED(); } else { turnOffLED(); } Call checkIfOverThreshold(500) to check if the sensor reading is over 500.

Clean, orderly Arduino programming relies on functions. Make time to find repetitious logic or blocks in your software that could become functions. Your future self will appreciate!

Why Use Functions in Arduino Programming?

Arduino programs grow long and complicated quickly. Functions arrange code into reusable chunks for tidying. Functions in Arduino programming have numerous advantages:


Functions let you reuse code. A function can be defined once and called whenever needed instead of copying and pasting the same code. Your programs run more efficiently and are easier to maintain.


Functions simplify complex logic into a basic, understandable block. That method can be called by anyone reading your code without understanding the specifics. Even beginners may grasp programming better.


Functions make it easy to find the cause of program errors. Instead of searching hundreds of lines of code, focus on specific functions to find and repair bugs.


Use descriptive function names to structure code into logical, easy-to-navigate pieces. The program structure is easier to grasp and use.

Arduino functions are defined using this structure:

Use void functionName() to define the function body and code.
The void function returns nothing. This invokes the function:

Function definitions should be placed at the top of your sketch, before setup() and loop() functions. You can call them from anywhere in your program.

Functionality is essential to writing clean Arduino code. Learn this fundamental programming concept—your future self will thank you!

Custom Arduino Functions

After mastering Arduino functions, you’ll want to write your own. Custom functions organize, simplify, and reuse logic. Make an Arduino work:

Define Function

Use void followed by your function name. Use () after the name and { to start the function body. As an example:

void myFunction()

} Optional: Add Parameters
You can pass function parameters. Add parameter data types and names to (). As an example:

void myFunction(int num, String text) {

Add Function Body Code
Enter the code to execute when the function is called between { }. Pin settings, sensor readings, calculations, etc. As an example:

void myFunction(int num, String text) { digitalWrite(num, HIGH); Serial.println(text); }
Call Function
You can invoke your custom function by name and (). If the function has parameters, pass arguments. As an example:

myFunction(13, “Hello!”); This calls myFunction() and passes 13 to num and “Hello!” to text. Run the function body code.

Following these methods, you’ll create Arduino functions quickly! Custom functions improve code structure and logic reuse. Try it and your Arduino programs will improve quickly. Have more questions? Let me know!

Sending Arduino Function Parameters
You’ll commonly give data to Arduino functions so they may operate on it. This data is termed parameters. Suppose you want to develop a function to turn on an LED for milliseconds. You could have this function:

In void blinkLED(int time), digitalWrite(LED_PIN, HIGH) turns on the LED. The delay function waits for milliseconds.
digitalWrite(LED_PIN, LOW); // Turn off LED
Set the time parameter to keep the LED on for milliseconds. Call this function and pass it a time value:

blink LED(200); // 200ms blink
When invoked, the function passes 200 to the time parameter. The function treats time as an integer variable with 200.

Separate several parameters with commas to pass them to a function:

doSomething(int, float, char) Parameters 1, 2, and 3 should be used within the function.
Pass all three parameters to call this function:

perform(10, 2.3, ‘A’);
The function has three parameters: 10, 2.3, and A.

Parameters let you create flexible functions that work with several input values. You can pass constants, variables, sensor readings, and other program-accessible data. Try developing Arduino functions with arguments to improve your code!

Standard Arduino Functions

The Arduino IDE has several built-in capabilities to simplify programming. Know these useful ones:

This makes a pin input or output. Use this in setup() to configure pins:

pinMode(ledPin, OUTPUT) powers an LED, while pinMode(buttonPin, INPUT) reads a button.Write()
This sets a digital output pin HIGH or LOW. Turn on an LED, relay, or other device:

digitalWrite(ledPin, HIGH); // Enables LED digitalWrite(ledPin, LOW); // Disables LED digitalRead()
This reads an INPUT pin and returns HIGH or LOW. Use it to read button, sensor, or input states:

buttonState = digitalRead(buttonPin); // Analog read of button stateWrite()
This writes PWM pulses to pins. Use it to control motor speed, LED brightness, etc.

AnalogWrite(ledPin, 255); // Full brightness analogWrite(127); // Half brightness analogWrite(motorPin, 200); // Medium motor speedRead()
This returns a pin’s analog value from 0 to 1023. It reads potentiometers, photoresistors, and other analog inputs:

SensorValue = analogRead(sensorPin); delay()
This pauses the program for milliseconds. Create delays and regulate timing:

delay(1000); // Waits 1 second delay(500); // Waits 0.5 seconds
These basic functions let you write complicated Arduino programs to read inputs, control outputs, and more. Enjoy your projects!

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