nov 4
This morning I got the output of a bend sensor (previously graphed) to pair with the frequency of a sine wave (courtesy of the Minim library). This was surprisingly simple.
I'm still using an inexact resistor value for the bend sensor. Its output is quite noisy though the input can be easily smoothed by using a piece of code similar to what I previously wrote for Gadgets.
For the Arduino side, I used something like this (he doesn't declare A0):
void setup() {
int analog_pin1 = 1;
// initialize the serial communication:
Serial.begin(9600);
}
void loop() {
// send the value of analog input 0:
Serial.println(analogRead(analog_pin1));
// wait a bit for the analog-to-digital converter
// to stabilize after the last reading:
delay(10);
}
For the processing end of things, I ended up splicing two pieces of code together. I figured out how to set up a sine wave using the polyphony example sketch (from the Minim library)
I didn't end up saving this version of things but it wasn't too different from the dual sine audio out which I just got working tonight (11-04-11 ~8:30PM). :
// [Dual] Graphing sketch (modified to graph two inputs and output two sine waves (using Minim)
// This program takes ASCII-encoded strings
// from the serial port at 9600 baud and graphs them. It expects values in the
// range 0 to 1023 [in a comma separated list (example: "10, 20, 30")], followed by a newline, or newline and carriage return
// Created 20 Apr 2005
// Updated 18 Jan 2008
// by Tom Igoe
// This example code is in the public domain.
import ddf.minim.*;
import ddf.minim.signals.*;
//import controlP5.*;
import processing.serial.*;
Minim minim;
AudioOutput out;
SineWave sine1;
SineWave sine2;
//TriangleWave tri;
//ControlP5 gui;
//public float triAmp = 0.5;
//public float triPan = 0;
//public float triFreq = 880;
//public float triFreq2 = 1;
float sin1Amp = 0.5; //these floats were public. I'm not sure why that was necessary. It was probably for the controlP5 GUI.
float sin1Pan = 0.5;
float sin1Freq = 440;
float sin2Amp = 0.5;
float sin2Pan = 0.5;
float sin2Freq = 330;
int sin1Glide = 50; //ms
int sin2Glide = 50; //ms
Serial myPort; // The serial port
int xPos = 1; // horizontal position of the graph
int x_size = 1000;
int y_size = 500;
int switcher = 0;
void setup () {
// set the window size:
size (x_size, y_size); // this line also had ", P3D" as a parameter of size. We're just using 2 dimensions right now.
minim = new Minim(this);
// get a stereo line out from Minim with a 2048 sample buffer, default sample rate is 44100, bit depth is 16
out = minim.getLineOut(Minim.STEREO, 8000);
// create a sine wave Oscillator, set to 440 Hz, at 0.5 amplitude, sample rate 44100 to match the line out
sine1 = new SineWave(440, 0.5, out.sampleRate());
sine2 = new SineWave(330, 0.5, out.sampleRate());
// set the portamento speed on the oscillator to 200 milliseconds
sine1.portamento(sin1Glide);
sine2.portamento(sin2Glide);
// add the oscillator to the line out
out.addSignal(sine1);
out.addSignal(sine2);
// create a triangle wave Oscillator
//tri = new TriangleWave(880, 0.5, out.sampleRate());
//tri.portamento(200);
//out.addSignal(tri);
// List all the available serial ports
println(Serial.list());
// I know that the first port in the serial list on my mac
// is always my Arduino, so I open Serial.list()[0].
// Open whatever port is the one you're using.
myPort = new Serial(this, Serial.list()[0], 9600);
// don't generate a serialEvent() unless you get a newline character:
myPort.bufferUntil('\n');
// set inital background:
background(0);
}
void draw () {
// everything happens in the serialEvent()
}
void serialEvent (Serial myPort) {
// get the ASCII string:
String inString = myPort.readStringUntil('\n');
if (inString != null) {
// trim off any whitespace:
inString = trim(inString);
int incomingValues[] = int(split(inString, ",")); // convert to an array of ints ***taken from serialEvent.pde line 8 in http://web.media.mit.edu/~plusea/downloads/code/p_rSkin_11x11.zip ***
//float inByte = float(inString);
sine1.setFreq(incomingValues[0]); //This updates the pitch of the sine wave every time the graph is drawn.
sine2.setFreq(incomingValues[1]);
//scale the output into the bounds of the box.
float graphline1 = map(incomingValues[0], 0, 1023, 0, height);
float graphline2 = map(incomingValues[1], 0, 1023, 0, height);
// draw the line:
switcher += 1;
if(switcher % 2 == 1){
stroke(0,0,255);
line(xPos, height, xPos, (height - graphline1));
}
else{
stroke(0, 255, 0);
line(xPos, height, xPos, (height - graphline2));
}
// at the edge of the screen, go back to the beginning:
if (xPos >= width) {
xPos = 0;
background(0);
}
else {
// increment the horizontal position:
xPos++;
}
}
}
This code is quite buggy. It works some of the time if I fidget with the sensors a bit (though I'm not entirely sure this is causing it).
As I don't know how to do transparency with processing (probably more trouble than it's worth) I interleaved the two inputs which made a pretty graph (file attached).
![[paper clip]](/courses/source/wiki_images/paper_clip_tilt.png)
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