TITLE:

It’s our AUDIO world! An Interactive Tech Audio Workshop

DESCRIPTION:

This workshop will include an interactive low-fi technology activity called “Paper Piano”. Participants will have the opportunity to build their own paper pianos and learn about circuits, visual mapping and sound! The panel portion of this event will include professional audio performance artists in dialogue about their practice, process, and community. Featured performance by Ali Santana.

https://vimeo.com/781920012

The PaperPiano was made at Princeton University under The Council on Science and Technology. Contributors include Aatish Bhatia, Bernat Guillen Pegueroles, and Sharon Lee De La Cruz.

The Arduino's job, in this case, is to map the different keys (known in the code as the keyReadings) in the paper piano into the musical notes of the pentatonic scale. Surprisingly everyone’s piano was different and mine had some inssues do to the double coat of conductive paint(made with a thin brush first and then with a thicker brush) so the values kept changing

// paper piano: here we divide an octave into the notes of the pentatonic scale

int sensorPin = A0;    // input pin
unsigned int sensorValue = 0;   // variable to store the value coming from the sensor
unsigned int sensorAvg = 0;
int step = 0;
int offset = 2; // if key readings are very close together in value, decrease this to 3 or so

// pentatonic scale- A4-A5
int pianoInput = 11;
int octave = 3; // default is 1. Change to 2 or 4 for higher octaves!
float scale[] = {440*octave, 495*octave, 556.875*octave, 660*octave, 742.5*octave}; // array storing frequencies for pentatonic scale

// REPLACE with readings from the 5 keys
float keyReadings[] = {276, 225, 195, 203, 171};

void setup() {
  // initialize serial communications at 2400 bps:
  Serial.begin(2400);
}

void loop() {

  // read the value from the sensor:
  sensorValue += analogRead(sensorPin);
  step = (step+1)%100;
  if(step == 0){
    sensorAvg = sensorValue/100;
    sensorValue = 0;
    Serial.println(sensorAvg);
  } 
  
  if(sensorAvg < 30){
    noTone(pianoInput);
  }
  else if(sensorAvg < keyReadings[4]+offset){
    tone(pianoInput, scale[4]);
  }
  else if(sensorAvg < keyReadings[3]+offset){
    tone(pianoInput, scale[3]);
  }
  else if(sensorAvg < keyReadings[2]+offset){
    tone(pianoInput, scale[2]);
  }
  else if(sensorAvg < keyReadings[1]+offset){ 
    tone(pianoInput, scale[1]);
  }
  else if(sensorAvg < keyReadings[0]+offset){
    tone(pianoInput, scale[0]);
  }  else{
 noTone(pianoInput);
  }
  
}

A better way to understand how this values are mapped, in Sharon’s word, is imagining a water current traveling in a tub, that would only be stop/ or called in certain points. This points would be the values for the keyReading.