Introduction to embedded programming

Embedded programming involves programming microcontrollers, which are small integrated circuits that bring together the essential elements of a computer. Microcontrollers can be found in a variety of everyday objects (robots, computers, cars…).

In this introductory course, you’ll learn how to use an Arduino board and its associated software, in order to assimilate the basics of embedded programming for your future personal projects.

For any comments or questions, feel free to email me at .

Requirements#

Software#

• A computer with Arduino IDE software.

Hardware#

The microcontroller#

• An Arduino microcontroller board (e.g. an Arduino UNO)
• A USB type A-B cable

Components#

Components are fairly easy to find on online sales sites. One piece of advice I can give is to buy component kits which already include the components listed below, with a few additional components that you can test on your own.

• Three colored LEDs
• One push button
• Three resistors of 220 ohms
• One resistor of 10 kilo-ohms
• A potentiometer
• An impedance buzzer
• A breadboard
• Some prototyping cables

Missions#

For each level, a circuit diagram will be proposed like the one below:

Try to build the circuit as shown. Once done, you can connect your Arduino board to your computer and open the Arduino IDE software. Let’s explore the interface quickly with a code to turn on the red LED:

• The verify button ☑️ allows you to check your code for errors before sending it to the board.
• The upload button ➡️ sends the compiled code to the Arduino board for execution.

We define an integer corresponding to the board pin to which we’ve connected the LED, (here pin 2):

const int ledPin = 2;

As the LED is an output (i.e. we send current from the Arduino board to the LED to turn it on), we configure the ledPin pin as such with the pinMode() function:

pinMode(ledPin, OUTPUT);

In the loop() function, we use digitalWrite() to set the LED to the HIGH state, thus turning it on:

digitalWrite(ledPin, HIGH);

After compiling and uploading, all the code included in the setup function will run only once (in this case, the definition of ledPin as a digital output). As for the code in the loop function, it will loop indefinitely!

Level 1 - Blinking#

Level 1 Wiring#

Solution

Level 2 - Traffic Light#

Level 2 Wiring#

Solution

Level 3 - Day, Night, Day…#

Level 3 Wiring#

Solution

Level 4 - Day, Night, soft version#

Level 4 Wiring#

Solution

Level 5 - ♪ Happy Birthday ♪#

Level 5 Wiring#

Frequencies of notes and (very) simplified “Happy Birthday” music sheet:#

Solution

Going further#

Congrats if you’ve completed all the levels! If it was too easy for you, try creating a project using all your components. For example: a variable brightness traffic light that beeps when it turns red to warn pedestrians? Feel free to search the web for fun tutorials.

Arduino is a great platform to learn embedded programming quickly and build small projects. But if you want to go further, you may look into STM32 microcontrollers — less beginner-friendly but widely used in industry and allows you to carry more complex projects.

Cheat Sheet#

Variables#

Operators#

Conditions#

if (x < 3) {
    printf("x is less than 3");
} else {
    printf("x is 3 or more");
}

Loops#

int x = 0;
while(x < 5){
    printf("I must not hit my computer.\n");
    x++;
}

int sum = 0;
for(int i = 0; i < 100; i++){
    sum += i;
}

Preprocessor directives#

// Inclusion of a library, in this case servo
#include <servo.h>

// Define constants
#define N 7
#define SIZE 3
#define SIZE2 6

Arrays#

int tab[SIZE] = {1, 8, 0, 5};
char tabchar[SIZE2] = {'c', 'h', 'r', 'o', 'm', 'a'};

// Initialize an array to 0
for (int i = 0; i < SIZE; i++) {
    tab[i] = 0;
}

Arduino Functions#

Mission Solutions#

These codes are suggested corrections written by me. Don’t treat them as the only solution — there are many valid ways to solve the same problem. Find the one that suits you best!

Level 1 Solution - Blinking#

 1const int ledPin = 2;
 2
 3void setup() {
 4  pinMode(ledPin, OUTPUT);
 5}
 6
 7void loop() {
 8  digitalWrite(ledPin, HIGH);
 9  delay(1000);
10
11  digitalWrite(ledPin, LOW);
12  delay(1000);
13}

Back to mission

Level 2 Solution - Traffic Light#

 1const int redLed = 2;
 2const int yellowLed = 3;
 3const int greenLed = 4;
 4
 5void setup() {
 6  pinMode(redLed, OUTPUT);
 7  pinMode(yellowLed, OUTPUT);
 8  pinMode(greenLed, OUTPUT);
 9}
10
11void loop() {
12  digitalWrite(redLed, HIGH);
13  digitalWrite(yellowLed, LOW);
14  digitalWrite(greenLed, LOW);
15  delay(1000);
16
17  digitalWrite(redLed, LOW);
18  digitalWrite(yellowLed, HIGH);
19  digitalWrite(greenLed, LOW);
20  delay(1000);
21
22  digitalWrite(redLed, LOW);
23  digitalWrite(yellowLed, LOW);
24  digitalWrite(greenLed, HIGH);
25  delay(1000);
26}

Back to mission

Level 3 Solution - Day, Night, Day…#

 1const int ledPin = 2;
 2const int buttonPin = 4;
 3
 4void setup() {
 5  pinMode(ledPin, OUTPUT);
 6  pinMode(buttonPin, INPUT);
 7}
 8
 9void loop() {
10  int buttonState = digitalRead(buttonPin);
11
12  if (buttonState == HIGH){
13    digitalWrite(ledPin, HIGH);
14  }
15  else{
16    digitalWrite(ledPin, LOW);
17  }
18}

Back to mission

Level 4 Solution - Day, Night, soft version#

 1const int ledPin = 3;
 2const int potPin = A0;
 3
 4void setup() {
 5  pinMode(ledPin, OUTPUT);
 6}
 7
 8void loop() {
 9  int potValue = analogRead(potPin);
10  int brightness = map(potValue, 0, 1023, 0, 255);
11
12  analogWrite(ledPin, brightness);
13}

Back to mission

Level 5 Solution - ♪ Happy Birthday ♪#

 1#define DO 262
 2#define RE 294
 3#define MI 330
 4#define FA 349
 5#define SOL 392
 6#define LA 440
 7#define LAd 466
 8#define DO2 524
 9
10#define SIZE 25
11
12const int buzzerPin = 2;
13const int buttonPin = 4;
14
15int frequences[SIZE] = {
16  DO, DO, RE, DO, FA, MI,
17  DO, DO, RE, DO, SOL, FA,
18  DO, DO, DO2, LA, FA, MI, RE,
19  LAd, LAd, LA, FA, SOL, FA
20
21};
22
23int durations[SIZE] = {
24  400, 200, 500, 500, 500, 900,
25  400, 200, 500, 500, 500, 900,
26  400, 200, 500, 500, 500, 500, 900,
27  400, 200, 500, 500, 500, 900
28};
29
30void setup() {
31  pinMode(buzzerPin, OUTPUT);
32  pinMode(buttonPin, INPUT);
33}
34
35void loop() {
36
37  int buttonState = digitalRead(buttonPin);
38  if (buttonState == HIGH){
39    happyBirthday();
40  }
41}
42
43
44void happyBirthday(){
45  for (int i = 0; i < SIZE; i++) {
46    tone(buzzerPin, frequences[i]);
47    delay(durations[i]);
48    noTone(buzzerPin);
49  }
50}

Back to mission

Credits#

• Writer: Ousmane THIONGANE
• Lastest update: May 2025
• Reviewer: Loubna LATRECHE