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Helmet Chords

martin.kiechle's picture
Tue, 11/15/2011 - 01:30 — martin.kiechle

Ankita, David, John, Stephen and Martin created an instrument to play chords on wine glasses. In order to have the hands free to play a melody on any conventional instrument along with the chords, we designed an input method for the head so that subtle tilts account for different keys. A video can be watched here: http://vimeo.com/32111887

 
 

Materials

  • 9 wine glasses
  • bicycle helmet
  • 3 servos
  • 3 FSRs
  • 1 potentiometer
  • styrofoam/wood board
  • 3 resistors
  • wires/breadboard
  • old batteries
  • plastic tubes

Arduino code

#include <Servo.h> 

 
Servo servoCh1;   // create servo object to control a servo 
Servo servoCh2;
Servo servoCh3;
 
int DEBUG = 0;
 
int fullAngle = 5; // variable to store the servo position 
int servoDelay = 100;
int potMin = 271, potMax = 436, potRange;
int delayMin = 50, delayMax = 500;
 
int pinFSR_left = 0;  // select the input pin for the sensors
int pinFSR_right = 1;
int pinFSR_front = 2;
int potPinSpeed = 3;
 
// FSRs
int valLeft = 0;
int valRight = 0;
int valFront = 0;
// potentiometer
int valSpeed = 0;
 
 
// jitter thresholds
int jitterThresh = 20;
 
void setup() 
{ 
  if(DEBUG)  Serial.begin(9600);
  servoCh1.attach(7);  
  servoCh2.attach(8); 
  servoCh3.attach(12);
    
  servoCh1.write(0);
  servoCh2.write(0); 
  servoCh3.write(0); 
  
  potRange = potMax - potMin;
} 
 
 
void loop() 
{ 
valLeft = analogRead(pinFSR_left); // read the value from the sensor, 0-1023
valRight = analogRead(pinFSR_right); // read the value from the sensor, 0-1023
valFront = analogRead(pinFSR_front);
valSpeed = analogRead(potPinSpeed);
 
if(DEBUG){
        Serial.print("FSR1 ");
        Serial.println(valLeft);
        Serial.print("FSR2 ");
        Serial.println(valRight);
        Serial.print("FSR3 ");
        Serial.println(valFront);
        Serial.print("POT ");
        Serial.println(valSpeed);
                remapVal();
        delay(1000);
}
        else{
        if(valFront > jitterThresh){
        playChord(2);
                }
        else{
         if(valLeft > jitterThresh)
        playChord(0);
        
         if(valRight > jitterThresh)
        playChord(1);
        }
        }
}
 
void playChord(int servo)
{
moveServo(servo, fullAngle);
delay(servoDelay);
moveServo(servo, 0);
 
delay(remapVal());
}
 
void moveServo(int num, int angle){
switch(num){
case 0: servoCh1.write(angle); break;
case 1: servoCh2.write(angle); break;
case 2: servoCh3.write(angle); break;
}
}
 
int remapVal(){
int inVal;
float relPos;
 
inVal = (valSpeed > potMax) ? potMax : valSpeed;
inVal = (valSpeed < potMin) ? potMin : valSpeed;
 
relPos = (float)(inVal - potMin) / (float)potRange;
return delayMin + (delayMax - delayMin) * relPos;
}
 
 
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