Mini Fan with a Light Show

// The fan, the light and the buzzer from the Elegoo kit, putting on a show.//// Wiring (top half of the breadboard unless it says otherwise; transistor flat// side facing you, legs left to right: E, B, C)://   Fan:    column 17: one end of a 220 ohm resistor + wire to Arduino pin 3//           column 20: transistor E leg + wire to Arduino GND//           column 21: transistor B leg + other end of the resistor//           column 22: transistor C leg + diode end WITHOUT the stripe + one motor wire//           column 26: diode end WITH the stripe + other motor wire + wire to Arduino 5V//   Light:  LED long leg in column 26, short leg in column 27, 220 ohm resistor//           from column 27 to column 31, wire from column 31 to Arduino pin 5.//           The long leg is on 5V, so the light comes on when pin 5 goes LOW.//   Buzzer: on the empty side of the breadboard, legs in two different rows.//           One leg's row goes to Arduino pin 9, the other leg's row to GND.//           (Pin 11 plays the same sound, so the buzzer can use either.)//// How it works://   - Plug it in: the show plays, then the fan keeps running with the light on.//   - Press the red reset button on the Arduino: everything turns off.//   - Press it again: the show plays again, then the fan keeps running.//   - From the computer: send "s" to play the show, or 0 (off) to 9 (full speed).const byte FAN_PIN = 3;const byte LIGHT_PIN = 5;const byte BUZZER_PIN = 9;        // buzzerOn() flips pins 9 and 11 directly,const byte BUZZER_PIN_SPARE = 11;  // so these can't be changed to other pins// Note frequencies, in Hz.const int NOTE_C5 = 523, NOTE_D5 = 587, NOTE_E5 = 659, NOTE_F5 = 698;const int NOTE_G5 = 784, NOTE_A5 = 880, NOTE_C6 = 1047;// Each song is pairs of (note, length). Length is in 16th notes, so// 4 = a quarter note, 8 = a half note. A length of 0 marks the end.const int TWINKLE[] PROGMEM = {  NOTE_C5, 4, NOTE_C5, 4, NOTE_G5, 4, NOTE_G5, 4, NOTE_A5, 4, NOTE_A5, 4, NOTE_G5, 8,  NOTE_F5, 4, NOTE_F5, 4, NOTE_E5, 4, NOTE_E5, 4, NOTE_D5, 4, NOTE_D5, 4, NOTE_C5, 8,  0, 0};const int JINGLE_BELLS[] PROGMEM = {  NOTE_E5, 4, NOTE_E5, 4, NOTE_E5, 8, NOTE_E5, 4, NOTE_E5, 4, NOTE_E5, 8,  NOTE_E5, 4, NOTE_G5, 4, NOTE_C5, 6, NOTE_D5, 2, NOTE_E5, 16,  NOTE_F5, 4, NOTE_F5, 4, NOTE_F5, 6, NOTE_F5, 2, NOTE_F5, 4, NOTE_E5, 4, NOTE_E5, 4, NOTE_E5, 2, NOTE_E5, 2,  NOTE_G5, 4, NOTE_G5, 4, NOTE_F5, 4, NOTE_D5, 4, NOTE_C5, 16,  0, 0};const int FANFARE[4] = {NOTE_C5, NOTE_E5, NOTE_G5, NOTE_C6};// Fan power for each speed setting, out of 255. Below about 90 the motor// doesn't have enough push to turn the blade.const int SPEEDS[10] = {0, 90, 110, 130, 150, 170, 190, 210, 235, 255};// The reset button restarts the program from the beginning, so these live in// a part of memory that the restart doesn't wipe. Unplugging does wipe it,// which is how the program tells "just plugged in" apart from "button pressed".const unsigned long REMEMBERED = 0xC0FFEE42;unsigned long memoryCheck __attribute__((section(".noinit")));byte fanWasOn __attribute__((section(".noinit")));byte lastSpeed __attribute__((section(".noinit")));int fanPower = 0;void setup() {  pinMode(FAN_PIN, OUTPUT);  pinMode(LIGHT_PIN, OUTPUT);  pinMode(BUZZER_PIN, OUTPUT);  pinMode(BUZZER_PIN_SPARE, OUTPUT);  light(0);  Serial.begin(9600);  if (memoryCheck != REMEMBERED) {    // Just plugged in.    memoryCheck = REMEMBERED;    fanWasOn = true;    lastSpeed = 9;    Serial.println("Plugged in: on");  } else {    // The reset button was pressed: flip between on and off.    fanWasOn = !fanWasOn;    Serial.println(fanWasOn ? "Button pressed: on" : "Button pressed: off");  }  if (lastSpeed < 1 || lastSpeed > 9) lastSpeed = 9;  if (fanWasOn) {    runShow();    setSpeed(lastSpeed);  } else {    beep(NOTE_G5, 100);  // a little "bye" so you know the button worked    delay(40);    beep(NOTE_C5, 160);  }}void loop() {  if (!Serial.available()) return;  char c = Serial.read();  if (c == 's') {    runShow();    fanWasOn = true;    setSpeed(lastSpeed);  } else if (c >= '0' && c <= '9') {    byte level = c - '0';    fanWasOn = level > 0;    if (level > 0) lastSpeed = level;    setSpeed(level);  }}// ---------- The show ----------void runShow() {  Serial.println("Show starting");  light(0);  fanRampTo(0);  delay(500);  // 1. Wake-up beeps.  for (byte i = 0; i < 4; i++) {    beep(FANFARE[i], 120);    delay(60);  }  delay(500);  // 2. A little tune, with the light blinking on every note.  playSong(TWINKLE, 120, false);  delay(600);  // 3. The fan slowly revs up. The light and the buzzer tick faster and  //    faster as it speeds up, like an engine.  fan(180);  // a stopped motor needs a push to get going  delay(200);  rev(110, 255, 6000);  light(255);  delay(1000);  // 4. Three swoops, slow and fast. The light dims and brightens with the  //    fan, and the buzzer chirps at the top of each one.  for (byte i = 0; i < 3; i++) swoop();  // 5. The fan winds down, ticking slower and slower.  rev(255, 100, 4000);  // 6. Finale: Jingle Bells. The light flashes on every note and the fan  //    speeds up on the high notes.  playSong(JINGLE_BELLS, 110, true);  // 7. Big finish: fanfare, three flashes, then full speed with the light on.  for (byte i = 0; i < 4; i++) {    beep(FANFARE[i], 90);    delay(30);  }  for (byte i = 0; i < 3; i++) {    light(255);    delay(120);    light(0);    delay(120);  }  fanRampTo(255);  light(255);  Serial.println("Show over");}// Plays a song. The light flashes on every note. If dance is true, the fan// speeds up on high notes and slows down on low ones.void playSong(const int *song, int msPer16th, bool dance) {  for (int i = 0; ; i += 2) {    int note = pgm_read_word(song + i);    int length = pgm_read_word(song + i + 1);    if (length == 0) break;    int ms = length * msPer16th;    buzzerOn(note);    light(255);    if (dance) fan(map(note, NOTE_C5, NOTE_C6, 100, 255));    delay(ms * 8 / 10);    buzzerOff();    light(0);    delay(ms - ms * 8 / 10);  }}// Moves the fan from one power to another over the given time. The light// blinks and the buzzer ticks along with it, faster when the fan is faster.void rev(int fromPower, int toPower, unsigned long ms) {  unsigned long start = millis();  unsigned long nextTick = start;  while (millis() - start < ms) {    int p = fromPower + (long)(toPower - fromPower) * (long)(millis() - start) / (long)ms;    fan(p);    if ((long)(millis() - nextTick) >= 0) {      int speed = constrain(p, 100, 255);      buzzerOn(map(speed, 100, 255, 400, 1200));      light(255);      delay(25);      buzzerOff();      light(0);      nextTick = millis() + map(speed, 100, 255, 450, 70);    }  }  fan(toPower);}// One slow-down-and-speed-up swoop, with the light following the fan.void swoop() {  for (int p = 255; p >= 110; p -= 3) {    fan(p);    light(map(p, 110, 255, 5, 255));    delay(18);  }  for (int p = 110; p <= 255; p += 3) {    fan(p);    light(map(p, 110, 255, 5, 255));    delay(18);  }  buzzerOn(NOTE_C6);  delay(70);  buzzerOff();}// ---------- Fan, light and buzzer ----------void fan(int power) {  fanPower = power;  analogWrite(FAN_PIN, power);}// The LED's long leg is on 5V, so it lights up when this pin goes LOW.void light(byte brightness) {  analogWrite(LIGHT_PIN, 255 - brightness);}// Changes the fan's speed setting gradually, so the motor doesn't grab a big// gulp of power all at once (that can make the Arduino restart).void setSpeed(byte level) {  int target = SPEEDS[level];  if (fanPower == 0 && target > 0 && target < 180) {    fanRampTo(180);  // a stopped motor needs a push to get going    delay(300);  }  fanRampTo(target);  light(level > 0 ? 255 : 0);  Serial.print("Speed ");  Serial.println(level);}void fanRampTo(int target) {  while (fanPower != target) {    if (fanPower < target) fan(min(fanPower + 5, target));    else fan(max(fanPower - 5, target));    delay(15);  }}void beep(unsigned int hz, int ms) {  buzzerOn(hz);  light(255);  delay(ms);  buzzerOff();  light(0);}// The buzzer runs on the Arduino's Timer1: every time the timer's count// reaches the top, it flips pins 9 and 11 on or off, which makes the sound.// (Arduino's built-in tone() would borrow the timer the fan uses on pin 3.)void buzzerOn(unsigned int hz) {  unsigned int top = 1000000UL / hz - 1;  // the timer counts 2 million times a second  OCR1A = top;  if (TCNT1 > top) TCNT1 = 0;  TCCR1A = 0;  TCCR1B = _BV(WGM12) | _BV(CS11);  // count up to the top and start over  TIMSK1 = _BV(OCIE1A);             // run the code below each time it gets there}ISR(TIMER1_COMPA_vect) {  PINB = _BV(PB1) | _BV(PB3);  // flip pins 9 and 11}void buzzerOff() {  TIMSK1 = 0;  TCCR1B = 0;  digitalWrite(BUZZER_PIN, LOW);  digitalWrite(BUZZER_PIN_SPARE, LOW);}