We created a musical instrument that focuses on manipulating MIDI files.

The basic idea of the instrument is to enable users to play musical variations of songs in almost infinite combinations of tempo, attack, decay and release.

Three potentiometers correlate to three transformations based on ASDR, which stands for attack, sustain, decay and release. We altered the attack decay and release which allowed a person using the device to create the variations.

• Attack time is the time taken for initial run-up of level from nil to peak, beginning when the key is first pressed. We mapped 1024 values of the potentiometer to 0 – 1.5s.
• Decay time is the time taken for the subsequent run down from the attack level to the designated sustain level. We mapped 1024 values of the potentiometer to 0-1.5s.
• Sustain level is the level during the main sequence of the sound’s duration, until the key is released. We kept this constant at 1.5
• Release time is the time taken for the level to decay from the sustain level to zero after the key is released. We mapped 1024 values of the potentiometer to 0-1.5s.

• We hooked up arduino and processing using firmata and then used a minim library. The FSR correlated to a tempo transformation.With this setup, we are able to transform any musical file into a remixed, completely different song.
• Video – > 
• https://drive.google.com/a/berkeley.edu/file/d/0ByHw8c_nutT2YzFRYV9YWUo4Tk0/view?usp=sharing

Code:

For this lab, I built a pinwheel powered by the dc motor. While making the pinwheel wasn’t very hard, a lot of thought and effort went into controlling its stability and speed on the motor’s spindle. After a very few spins, the spindle makes the hole in the pinwheel bigger causing the pinwheel paper to lose contact with the motor which further results in loss of control over the motion of the pinwheel and the speed.

To circumvent the problem, I used a twist tie to harness the motion of the spindle and transfer it onto the pinwheel. The arrangement is depicted in the photo attached. I then hosted the pinwheel and motor on a candy holder to allow for the pinwheel to get enough space to spin. I also placed a sticker on the top of the spindle hole to prevent the paper pinwheel from flying away.

https://drive.google.com/a/berkeley.edu/file/d/0ByHw8c_nutT2LU9EcGRNMWR2b28/view?usp=sharing

Code:

/*
* one pot fades one motor
* modified version of AnalogInput
* by DojoDave <http://www.0j0.org>
* http://www.arduino.cc/en/Tutorial/AnalogInput
* Modified again by dave
*/

int potPin = 0; // select the input pin for the potentiometer
int motorPin = 9; // select the pin for the Motor
int val = 0; // variable to store the value coming from the sensor
void setup() {
pinMode(motorPin, OUTPUT);
Serial.begin(9600);
}
void loop() {
val = analogRead(potPin); // read the value from the sensor, between 0 – 1024
Serial.println(val);
analogWrite(motorPin, val/4); // analogWrite can be between 0-255
}

For the programming part of the lab, I created a visualization which starts with a circle at the corner of the screen and a rectangle in the middle. As force is exerted on the FSR, the circle on the left corner starts travelling diagonally across the screen and the edges of the rectangle start rounding. At a point, the circle hides behind the rectangle as if it were a coin that went into a pot/jar.

This inspired mechanical part of my lab today. I used a pot to make contact with the FSR. Then I used a small ziploc bag full of coins to exert pressure on the FSR. The pressure could be measured by the number of quarters.

Arduino Sketch:

/* FSR testing sketch.

Connect one end of FSR to 5V, the other end to Analog 0.
Then connect one end of a 10K resistor from Analog 0 to ground
Connect LED from pin 11 through a resistor to ground

For more information see www.ladyada.net/learn/sensors/fsr.html */

int fsrAnalogPin = 0; // FSR is connected to analog 0
int LEDpin = 13; // connect Red LED to pin 11 (PWM pin)
int fsrReading; // the analog reading from the FSR resistor divider
int LEDbrightness;

void setup(void) {
Serial.begin(9600); // We’ll send debugging information via the Serial monitor
pinMode(LEDpin, OUTPUT);
}

void loop(void) {
fsrReading = analogRead(fsrAnalogPin);
//Serial.print(“Analog reading = “);
//Serial.println(fsrReading);

// we’ll need to change the range from the analog reading (0-1023) down to the range
// used by analogWrite (0-255) with map!
LEDbrightness = map(fsrReading, 0, 1023, 0, 255);
// LED gets brighter the harder you press
analogWrite(LEDpin, LEDbrightness);

delay(100);
Serial.println(fsrReading);
}

Processing Sketch:

/* PROCESSING SKETCH
* Arduino Ball Paint
* (Arduino Ball, modified 2008)
* ———————-
*
* Draw a ball on the screen whose size is
* determined by serial input from Arduino.
*
* Created 21 September 2016
* Noura Howell
*/
import processing.serial.*;
// Change this to the portname your Arduino board
String portname = “COM3″;
Serial port;
String buf=””;
int cr = 13; // ASCII return == 13
int lf = 10; // ASCII linefeed == 10

int serialVal = 0;

void setup() {
size(700,700);
frameRate(10);
smooth();
background(40,40,40);
//noStroke();
port = new Serial(this, portname, 9600);
}

void draw() {
// erase the screen
background(40, 40, 40);

// draw the ball
fill(255, 255, 255);
//ellipse(150,150,serialVal,serialVal);
ellipse(serialVal,serialVal,150,150);
rect(200, 300, 300, 300, serialVal,serialVal, serialVal, serialVal);
}

// called whenever serial data arrives
void serialEvent(Serial p) {
int c = port.read();
if (c != lf && c != cr) {
buf += char(c);
}
if (c == lf) {
serialVal = int(buf);
println(“val=”+serialVal);
buf = “”;
}
}