Upgrading my old coffee maker to play the Super Mario Bros. theme song when ready – Arduino + Piezo Buzzer.

4 minutes after I power it on:

I have an old coffee maker that I’ve wanted to mod for quite a while. It has no features (aside from an on/off switch) and just makes coffee – ok. After some thinking, I decided I’d add a simple beep or melody that is triggered after a set duration when the unit is switched on. Something to remind me that my coffee is ready. I eventually decided to go with the Super Mario Bros. theme song. This project is not meant to be taken seriously. Also, I am working with mains voltage so if you’re following along, be careful.

Items Needed / Assembly:

(*info: most links in the list below link to Amazon items through my Amazon Affiliate account. It’s often less expensive to search on eBay if you don’t mind waiting for shipments from China, etc.) :

Here are the items laid out on my table:

Items needed
Items needed.

1) Open the bottom of the coffee maker.

There were 2 security screws:

After some messing around, I found that using these types of scissors seems to work:

It took some time unscrewing the security screws with my pliers and scissors, but it eventually worked. You have to grab the scissors as close to the bottom as you can and gradually turn; reorient your position; turn again, and so on. You are better off using a tool made for this.

2) Wire it all up.

The general idea is to tap into the mains wires on the switch and convert that AC voltage to 5v DC – used to power the Arduino (using the power converter mentioned above). From there, I will add the said Arduino and connect the piezo buzzer to play a tune after a 4-minute delay.

Here are some images of me wiring the power supply module to the mains switch wires:

Now I was able to connect the Arduino Nano to the 5v output of the power supply:

And finally, I was ready to connect the piezo buzzer to GPIO pin 9:

Powered it up:

Everything has powered up fine. Next, I’ll add the Arduino sketch that will play the Super Mario Bros. theme.

3) The Super Mario Bros. Arduino Sketch.

After toying with the Arduino “tone()” function, making beeps, etc. I figured I should find something more interesting. I did some searching and came across this blog post: https://www.princetronics.com/supermariothemesong/. The author modified the original Arduino sketch that was posted here: http://www.linuxcircle.com/2013/03/31/playing-mario-bros-tune-with-arduino-and-piezo-buzzer/. The Arduino sketch plays parts of the Super Mario Bros. song through a piezo buzzer. We’ll use the modified version.

All I need to add to the sketch is a ~4-minute timer delay (about how long it takes this to brew a few cups) + a boolean condition to make sure the melody only plays once-through while the coffee maker is on.

So to recap how this works: (when the switch is flipped on) voltage is routed from mains -> 5v through the power converter. The Arduino is then powered from this 5v output, starting the delay-timer that runs for 4 minutes, which finally triggers the Super Mario Bros. melody as a reminder that your coffee is ready.

Here is the full Arduino sketch with the delay timer + boolean flag:

/*
  Arduino Mario Bros Tunes
  With Piezo Buzzer and PWM

  Connect the positive side of the Buzzer to pin 3,
  then the negative side to a 1k ohm resistor. Connect
  the other side of the 1 k ohm resistor to
  ground(GND) pin on the Arduino.

  by: Dipto Pratyaksa
  last updated: 31/3/13
*/

/*************************************************
 * Public Constants
 *************************************************/

#define NOTE_B0  31
#define NOTE_C1  33
#define NOTE_CS1 35
#define NOTE_D1  37
#define NOTE_DS1 39
#define NOTE_E1  41
#define NOTE_F1  44
#define NOTE_FS1 46
#define NOTE_G1  49
#define NOTE_GS1 52
#define NOTE_A1  55
#define NOTE_AS1 58
#define NOTE_B1  62
#define NOTE_C2  65
#define NOTE_CS2 69
#define NOTE_D2  73
#define NOTE_DS2 78
#define NOTE_E2  82
#define NOTE_F2  87
#define NOTE_FS2 93
#define NOTE_G2  98
#define NOTE_GS2 104
#define NOTE_A2  110
#define NOTE_AS2 117
#define NOTE_B2  123
#define NOTE_C3  131
#define NOTE_CS3 139
#define NOTE_D3  147
#define NOTE_DS3 156
#define NOTE_E3  165
#define NOTE_F3  175
#define NOTE_FS3 185
#define NOTE_G3  196
#define NOTE_GS3 208
#define NOTE_A3  220
#define NOTE_AS3 233
#define NOTE_B3  247
#define NOTE_C4  262
#define NOTE_CS4 277
#define NOTE_D4  294
#define NOTE_DS4 311
#define NOTE_E4  330
#define NOTE_F4  349
#define NOTE_FS4 370
#define NOTE_G4  392
#define NOTE_GS4 415
#define NOTE_A4  440
#define NOTE_AS4 466
#define NOTE_B4  494
#define NOTE_C5  523
#define NOTE_CS5 554
#define NOTE_D5  587
#define NOTE_DS5 622
#define NOTE_E5  659
#define NOTE_F5  698
#define NOTE_FS5 740
#define NOTE_G5  784
#define NOTE_GS5 831
#define NOTE_A5  880
#define NOTE_AS5 932
#define NOTE_B5  988
#define NOTE_C6  1047
#define NOTE_CS6 1109
#define NOTE_D6  1175
#define NOTE_DS6 1245
#define NOTE_E6  1319
#define NOTE_F6  1397
#define NOTE_FS6 1480
#define NOTE_G6  1568
#define NOTE_GS6 1661
#define NOTE_A6  1760
#define NOTE_AS6 1865
#define NOTE_B6  1976
#define NOTE_C7  2093
#define NOTE_CS7 2217
#define NOTE_D7  2349
#define NOTE_DS7 2489
#define NOTE_E7  2637
#define NOTE_F7  2794
#define NOTE_FS7 2960
#define NOTE_G7  3136
#define NOTE_GS7 3322
#define NOTE_A7  3520
#define NOTE_AS7 3729
#define NOTE_B7  3951
#define NOTE_C8  4186
#define NOTE_CS8 4435
#define NOTE_D8  4699
#define NOTE_DS8 4978

#define melodyPin 9
//Mario main theme melody
int melody[] = {
  NOTE_E7, NOTE_E7, 0, NOTE_E7,
  0, NOTE_C7, NOTE_E7, 0,
  NOTE_G7, 0, 0,  0,
  NOTE_G6, 0, 0, 0,

  NOTE_C7, 0, 0, NOTE_G6,
  0, 0, NOTE_E6, 0,
  0, NOTE_A6, 0, NOTE_B6,
  0, NOTE_AS6, NOTE_A6, 0,

  NOTE_G6, NOTE_E7, NOTE_G7,
  NOTE_A7, 0, NOTE_F7, NOTE_G7,
  0, NOTE_E7, 0, NOTE_C7,
  NOTE_D7, NOTE_B6, 0, 0,

  NOTE_C7, 0, 0, NOTE_G6,
  0, 0, NOTE_E6, 0,
  0, NOTE_A6, 0, NOTE_B6,
  0, NOTE_AS6, NOTE_A6, 0,

  NOTE_G6, NOTE_E7, NOTE_G7,
  NOTE_A7, 0, NOTE_F7, NOTE_G7,
  0, NOTE_E7, 0, NOTE_C7,
  NOTE_D7, NOTE_B6, 0, 0
};
//Mario main them tempo
int tempo[] = {
  12, 12, 12, 12,
  12, 12, 12, 12,
  12, 12, 12, 12,
  12, 12, 12, 12,

  12, 12, 12, 12,
  12, 12, 12, 12,
  12, 12, 12, 12,
  12, 12, 12, 12,

  9, 9, 9,
  12, 12, 12, 12,
  12, 12, 12, 12,
  12, 12, 12, 12,

  12, 12, 12, 12,
  12, 12, 12, 12,
  12, 12, 12, 12,
  12, 12, 12, 12,

  9, 9, 9,
  12, 12, 12, 12,
  12, 12, 12, 12,
  12, 12, 12, 12,
};
//Underworld melody
int underworld_melody[] = {
  NOTE_C4, NOTE_C5, NOTE_A3, NOTE_A4,
  NOTE_AS3, NOTE_AS4, 0,
  0,
  NOTE_C4, NOTE_C5, NOTE_A3, NOTE_A4,
  NOTE_AS3, NOTE_AS4, 0,
  0,
  NOTE_F3, NOTE_F4, NOTE_D3, NOTE_D4,
  NOTE_DS3, NOTE_DS4, 0,
  0,
  NOTE_F3, NOTE_F4, NOTE_D3, NOTE_D4,
  NOTE_DS3, NOTE_DS4, 0,
  0, NOTE_DS4, NOTE_CS4, NOTE_D4,
  NOTE_CS4, NOTE_DS4,
  NOTE_DS4, NOTE_GS3,
  NOTE_G3, NOTE_CS4,
  NOTE_C4, NOTE_FS4, NOTE_F4, NOTE_E3, NOTE_AS4, NOTE_A4,
  NOTE_GS4, NOTE_DS4, NOTE_B3,
  NOTE_AS3, NOTE_A3, NOTE_GS3,
  0, 0, 0
};
//Underwolrd tempo
int underworld_tempo[] = {
  12, 12, 12, 12,
  12, 12, 6,
  3,
  12, 12, 12, 12,
  12, 12, 6,
  3,
  12, 12, 12, 12,
  12, 12, 6,
  3,
  12, 12, 12, 12,
  12, 12, 6,
  6, 18, 18, 18,
  6, 6,
  6, 6,
  6, 6,
  18, 18, 18, 18, 18, 18,
  10, 10, 10,
  10, 10, 10,
  3, 3, 3
};

boolean finished_song = false;

void setup(void)
{
  pinMode(melodyPin, OUTPUT);//buzzer
  pinMode(13, OUTPUT);//led indicator when singing a note

}
void loop()
{
  delay(240000); //4 minutes
  if(finished_song == false){
    //sing the tunes
    sing(1);
    sing(1);
    sing(2);
    finished_song = true;
  }
}
int song = 0;

void sing(int s) {
  // iterate over the notes of the melody:
  song = s;
  if (song == 2) {
    Serial.println(" 'Underworld Theme'");
    int size = sizeof(underworld_melody) / sizeof(int);
    for (int thisNote = 0; thisNote < size; thisNote++) {

      // to calculate the note duration, take one second
      // divided by the note type.
      //e.g. quarter note = 1000 / 4, eighth note = 1000/8, etc.
      int noteDuration = 1000 / underworld_tempo[thisNote];

      buzz(melodyPin, underworld_melody[thisNote], noteDuration);

      // to distinguish the notes, set a minimum time between them.
      // the note's duration + 30% seems to work well:
      int pauseBetweenNotes = noteDuration * 1.30;
      delay(pauseBetweenNotes);

      // stop the tone playing:
      buzz(melodyPin, 0, noteDuration);

    }

  } else {

    Serial.println(" 'Mario Theme'");
    int size = sizeof(melody) / sizeof(int);
    for (int thisNote = 0; thisNote < size; thisNote++) {

      // to calculate the note duration, take one second
      // divided by the note type.
      //e.g. quarter note = 1000 / 4, eighth note = 1000/8, etc.
      int noteDuration = 1000 / tempo[thisNote];

      buzz(melodyPin, melody[thisNote], noteDuration);

      // to distinguish the notes, set a minimum time between them.
      // the note's duration + 30% seems to work well:
      int pauseBetweenNotes = noteDuration * 1.30;
      delay(pauseBetweenNotes);

      // stop the tone playing:
      buzz(melodyPin, 0, noteDuration);

    }
  }
}

void buzz(int targetPin, long frequency, long length) {
  digitalWrite(13, HIGH);
  long delayValue = 1000000 / frequency / 2; // calculate the delay value between transitions
  //// 1 second's worth of microseconds, divided by the frequency, then split in half since
  //// there are two phases to each cycle
  long numCycles = frequency * length / 1000; // calculate the number of cycles for proper timing
  //// multiply frequency, which is really cycles per second, by the number of seconds to
  //// get the total number of cycles to produce
  for (long i = 0; i < numCycles; i++) { // for the calculated length of time...
    digitalWrite(targetPin, HIGH); // write the buzzer pin high to push out the diaphram
    delayMicroseconds(delayValue); // wait for the calculated delay value
    digitalWrite(targetPin, LOW); // write the buzzer pin low to pull back the diaphram
    delayMicroseconds(delayValue); // wait again or the calculated delay value
  }
  digitalWrite(13, LOW);

}

That is it for the sketch. Uploading it to my Arduino Nano:

(carefully) Test it:

4) Put everything (safely) in the *cool side of the coffee maker.

At this point, I just needed to cautiously put everything inside the bottom portion of the coffee maker. The space directly under the heating plate gets too hot. I just put everything to the right of it. I used a watertight plastic box to safely house both the power converter and the Arduino.

If everything worked, after 4 minutes from when I switched it on, the Super Mario Bros. theme should start playing:

Conclusion

There are definitely better mods for coffee makers than this. This one just happens to be kinda fun. However, I don’t plan on giving up my nano to this project. I’ll use it for a while and see if I like it. When I revisit this project, I’ll bring the esp8266 into play and see what else we can do.

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