I'm working on an installation and the values from the proximity sensors (Sharp long- and mid-distance IR sensors) 'flicker' or change very fast (check the video here: http://www.youtube.com/watch?v=yxS_sV3b674). This problem renders the whole project useless, as it was supposed to generate music and change values (cutoff, pitch, etc.). I've bee trying to find the answer for ages, with not much success. Any ideas welcome...

video works now.
hmm strange results.
what is actually the right result ? or what should it look like.
i cant read what this is showing me.
it always jumps from left to right.  that what would be the correct value and what is the error ?

The actual result should be smoother. As I move my hand slowly towards or away the sensors, the values flickr/jump/bounce. The values are represented with the x and y position of the cross. By the way, the sketch:

//use the 'standard firmata' for processing library!

import cc.arduino.*;
import processing.serial.*;
import promidi.*;
PFont font;
Arduino arduino;
MidiIO midiIO;
MidiOut midiOut;
int sensor1;
int sensor2;
int cs1= width/2;
Note note;

void setup(){
size(500,500);
arduino = new Arduino(this, Arduino.list()[1], 57600);
arduino.pinMode(7, Arduino.INPUT);
arduino.pinMode(6, Arduino.INPUT);
arduino.pinMode(5, Arduino.INPUT);
midiIO = MidiIO.getInstance(this);
midiOut = midiIO.getMidiOut(1,"IAC Driver - Bus 1");
midiIO.printDevices();
println(Arduino.list());
}
void draw(){
background(0);
fill(255);
smooth();
rectMode(CENTER);
noStroke();
int cs1 = constrain(sensor1,0,height);
int cs2 = constrain(sensor2,0,500);
rect(cs2,cs1,10,40);
rect(cs2,cs1,40,10);
sensor1 = arduino.analogRead(0);
sensor2 = arduino.analogRead(1);

midiOut.sendController(new Controller(1 sensor1=3*sensor1*sensor1-2*sensor1*sensor1;,sensor1/4));
midiOut.sendController(new Controller(2,sensor2/4));
println(cs2);
delay(10);

if (arduino.digitalRead(7) == Arduino.LOW){
 note = new Note(64,64,1);
 midiOut.sendNote(note);
 fill(255);
 ellipse(width*0.3,height/2,80,80);
 println("HIGH");
}
else {
 noFill();
 stroke(255);
 ellipse(width*0.3,height/2,80,80);
}
}

By the way, just realised that the output of the sensor is digital... Spec sheet here: http://tiny.cc/ma20j

That puts the whole scenario in a new perspective, as I have used the sensor with analog inputs. Should I try it with digital pin?

As  I understand the spec sheet, the output is pure analog. The output-voltage is updatet every x milliseconds, but no digital information.
Of course, software debouncing or analog will cause a retarded reaction.

You can do the smoothing on the Arduino.  See the smoothing tutorial on the Arduino tutorials page

blindfish wrote on Jan 3^rd, 2010, 2:39pm:


Thanks dude, but I'd rather do it in Processing. I know there's a simple way, just cannot find it... Will try the Arduino-stuff...

Good to read this thread, having the same problem with the sharp ir sensor, and its sending my graph a bit haywire with the noise. Links provided should be of help.

Thanks folks!