4 Starter Arduino Projects for Classrooms

/*
Christmas Ornament Project - Damien Kee, 2019

Waits for a button press, and then plays Jingle Bells and flashes LED's

Hardware:
LED and Resistors (330 ohm to 1k should be fine) on Pins 8-13
Buzzer connected to 6 and GND
Button connected to 4 and GND

Music code original by Tom Igoe (2010) - http://www.arduino.cc/en/Tutorial/Tone

*/

// This list defines the note name and the frequency required to play it.  ie.  A concert pitch A in 
// the 4th octave (A4) is 440Hz
#define C4  262
#define CS4 277
#define D4  294
#define DS4 311
#define E4  330
#define F4  349
#define FS4 370
#define G4  392
#define GS4 415
#define A4  440
#define AS4 466
#define B4  494
#define C5  523

int buzzer_pin = 6;   //Buzzer is connected to pin 6 and GND
int button_pin = 4;   //Button is connected to 4 and GND
int which_LED_is_on = 8;   // Variable to keep track of which LED is currently turned on

//Jingle bells melody.  An array is created, and each note defined within the array
int melody[] = {E4, E4, E4, E4, E4, E4, E4, G4, C4, D4, E4, F4, F4, F4, F4, F4, E4, E4, E4, E4, D4, D4, E4, D4, G4};

//Jingle Bell rhythm.  An array is created, where each entry in the array defines the length of the note in the melody array
// 1 = semibreve, 2=minum, 4=crotchet, 8=quaver
int rhythm[] = {4, 4, 2, 4, 4, 2, 4, 4, 4, 4, 1, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 2, 2};

// Keep track of how many notes are in your melody
int number_of_notes = 25;


void setup() {
  // put your setup code here, to run once:
  pinMode(button_pin, INPUT_PULLUP);
  pinMode(13, OUTPUT);
  pinMode(12, OUTPUT);
  pinMode(11, OUTPUT);
  pinMode(10, OUTPUT);
  pinMode(9, OUTPUT);
  pinMode(8, OUTPUT);
  
}

void loop() {
  // put your main code here, to run repeatedly:

  // If the button is pressed, then run routine.  When the button is pressed, it connects the pin to GND, hence looking for the LOW signal
  if (digitalRead(button_pin) == LOW ) { 
    // Create a 'for' loop.  Each time through the loop a melody note and the corresponding rhythm in each array are used with the tone() command
    // It will play through all the notes in the melody array using sizeof(melody).  Arrays are referenced from 0, so we need to subtract 1
    // Make sure rhythm array is the same length as melody array  
    for (int thisNote = 0 ; thisNote< number_of_notes ; thisNote++) {

      //Turn on next LED
      digitalWrite(which_LED_is_on, HIGH);
      
      //The length of the note in miliseconds.  ie.  A quaver(8)  is 1000/8 = 125ms
      int noteDuration = 1000 / rhythm[thisNote];
  
      //make sure there is a very slight gap between each note by slightly shortening the notes.  10 milliseconds works well
      tone(buzzer_pin, melody[thisNote], noteDuration-10);
  
      //GIve the buzzer enough time to play the note (plus slight gap)
      delay(noteDuration) ;

      // Turn of LED
      digitalWrite(which_LED_is_on, LOW);

      // Increment the counter to point to the next LED
      if (which_LED_is_on == 13) {
        which_LED_is_on = 8;
      } else {
        which_LED_is_on++;
      }
      
    }
    noTone(buzzer_pin);
  }

}

/*
 * Basic Gripper - Damien Kee 2020
 * Servo motor connected to Pin 3
 * Potentiometer connected to A0
 * 
 * The Arduino reads in the potentiometer value (input).  This input will be between 0 and 1024
 * The "map" function then takes this input and scales it to be between 0 and 110. 
 * The 0 and 110 are figured out experimentally by seeing what angles the servo motor needs to rotate to
 */

#include <Servo.h>

Servo hand;  
int input = 0;
int output = 0;

void setup() {
  hand.attach(3);
  Serial.begin(9600);
}

void loop() {
  input = analogRead(A0);                 // Read in the Potentiometer value 
  output = map(input, 0, 1024, 0, 180);   // Convert the input to a number the servo can use
  hand.write(output);                     // Make the servo move to that location
  Serial.println(output);                 // Send the servo angle back to the computer (Serial Monitor) for debugging
  delay(100);                             // Slight delay to allow the servo to catch up
  
}

/*
 * Garage Door Opener - Damien Kee 2019
 * Sevo motor connected to pin 10
 * Red and Green LED's on 8 and 9 (330ohm resistors to GND)
 * Button on Pin 3
 */

//Include the Servo Library that does all the nitty-gritty servo code
#include <Servo.h>

//LEDs are connected to pins 8 and 9, button is on 4
int GREEN = 9;
int RED = 8;
int button_pin = 4;

Servo door;   //Define the Servo object

void setup() {
  // put your setup code here, to run once:
  door.attach(10);      // Tell the Arduino there is a Servo attached to pin 10
  pinMode(GREEN, OUTPUT);
  pinMode(RED, OUTPUT);
  pinMode(button_pin, INPUT_PULLUP);
}

void loop() {
  door.write(5);            // Tell the servo to go to the 0 degree position
  digitalWrite(RED, HIGH);  // Red light on, green light off
  digitalWrite(GREEN, LOW);

  //If the button gets pressed
  if (digitalRead(button_pin) == LOW) {
    digitalWrite(RED, LOW);
    digitalWrite(GREEN, HIGH);
    door.write(90);
    delay(2000);
  }
}

/*
 * Two way Traffic Lights - Damien Kee 2020
 * 2 sets of traffic lights (Green, Yellow, Red). One facing North, the other facing west
 * Traffic lights change through a sequence to ensure no crashes
 * LED's have a 330 ohm resistor in series to limit the current.
 */

int north_red = 8;
int north_yellow = 9;
int north_green = 10;
int west_red = 11;
int west_yellow = 12;
int west_green = 13;

void setup() {
  pinMode(north_red, OUTPUT);
  pinMode(north_yellow, OUTPUT);
  pinMode(north_green, OUTPUT);
  pinMode(west_red, OUTPUT);
  pinMode(west_yellow, OUTPUT);
  pinMode(west_green, OUTPUT);

}

// Not the most efficient code, but does highlight the state of every LED for each part of the sequence
void loop() {
  digitalWrite(north_red, HIGH);
  digitalWrite(north_yellow, LOW);
  digitalWrite(north_green, LOW);
  digitalWrite(west_red, LOW);
  digitalWrite(west_yellow, LOW);
  digitalWrite(west_green, HIGH);
  delay(3000);
  
  digitalWrite(north_red, HIGH);
  digitalWrite(north_yellow, LOW);
  digitalWrite(north_green, LOW);
  digitalWrite(west_red, LOW);
  digitalWrite(west_yellow, HIGH);
  digitalWrite(west_green, LOW);
  delay(1000);
  
  digitalWrite(north_red, HIGH);
  digitalWrite(north_yellow, LOW);
  digitalWrite(north_green, LOW);
  digitalWrite(west_red, HIGH);
  digitalWrite(west_yellow, LOW);
  digitalWrite(west_green, LOW);
  delay(1000);

  digitalWrite(north_red, LOW);
  digitalWrite(north_yellow, LOW);
  digitalWrite(north_green, HIGH);
  digitalWrite(west_red, HIGH);
  digitalWrite(west_yellow, LOW);
  digitalWrite(west_green, LOW);
  delay(3000);

  digitalWrite(north_red, LOW);
  digitalWrite(north_yellow, HIGH);
  digitalWrite(north_green, LOW);
  digitalWrite(west_red, HIGH);
  digitalWrite(west_yellow, LOW);
  digitalWrite(west_green, LOW);
  delay(1000);

  digitalWrite(north_red, HIGH);
  digitalWrite(north_yellow, LOW);
  digitalWrite(north_green, LOW);
  digitalWrite(west_red, HIGH);
  digitalWrite(west_yellow, LOW);
  digitalWrite(west_green, LOW);
  delay(1000);


}