arduino_setup.pde

int leftPin = 0;
int rightPin = 1;

int leftMin = 400;
int leftMax = 600;

int rightMin = 400;
int rightMax = 600;

/*
int leftMin = 600;
int leftMax = 940;

int rightMin = 580;
int rightMax = 930;
*/

void setup() {
  Serial.begin(9600); 
}

void loop() {
  int leftSig = analogRead(leftPin);
  int rightSig = analogRead(rightPin);
  
  leftSig = constrain(leftSig, leftMin, leftMax);
  leftSig = map(leftSig, leftMin, leftMax, 0, 255);
//  Serial.println(leftSig);
  Serial.print(leftSig, BYTE);
  delay(10);

  rightSig = constrain(rightSig, rightMin, rightMax);
  rightSig = map(rightSig, rightMin, rightMax, 0, 255);
//  Serial.println(rightSig);
  Serial.print(rightSig, BYTE);
  delay(10);
  
//  delay(1000 / 10); 
}

csound_photo_theremin.pde

/*
 Csound Photo-Theremin
 By Jacob Joaquin
 csoundblog.com
 
 Uses two photoresistors to control amplitude and pitch of a Csound
 synthesizer, emulating a Theremin.
 
 Code borrows from Processing example Serial Duplex by Tom Igoe.
 Sand instrument adapted from Trapped in Convert by Dr. Richard Boulanger
 */

import processing.serial.*;
import csoundo.*;

Csoundo cs;

Serial myPort;
int byte0 = 0;
int byte1 = 0;

void setup() {
    size(640, 480);
    frameRate(30);
    background(0);
    smooth();
    println(Serial.list());

    // Tom Igoe says:
    // I know that the first port in the serial list on my macfl
    // is always my  FTDI adaptor, so I open Serial.list()[0].
    // In Windows, this usually opens COM1.
    // Open whatever port is the one you're using.
    String portName = Serial.list()[0];
    myPort = new Serial(this, portName, 9600);

    cs = new Csoundo(this, "synth.csd");
    //cs = new Csoundo(this, "trapped_instr.csd");
    cs.run();
}

void draw() {
      noStroke();
      fill(0, 32);
      rect(0, 0, width, height);  
      stroke(255);
      float right = cs.getChn("right");
      float left = 1 - cs.getChn("left");
      line(right * width, 0, right * width, height);
      line(0, left * height, width, left * height);
}

void serialEvent(Serial myPort) {
    byte[] buffer = new byte[2];

    while(myPort.available() > 1) {
        buffer = myPort.readBytes();

        byte0 = convert(buffer[0]);
        byte1 = convert(buffer[1]);

        cs.setChn("left", map(byte0, 0, 255, 0, 1));
        cs.setChn("right", map(byte1, 0, 255, 1, 0));
    }
}

// Converts signed to unsigned
int convert(byte b) {
    if (b < 0) {
        return 127 + (129 - b * -1);
    }

    return b;
}

synth.csd

<CsoundSynthesizer>
<CsInstruments>
sr = 44100
kr = 441
ksmps = 100
nchnls = 1
0dbfs = 1

gi_wave ftgen 1, 0, 8192, 9, 0.5, 1, 0

chn_k "left", 1
chn_k "right", 1
chnset 0, "left"
chnset 0, "right"

instr 1
    idur = p3
    iamp = p4
    
    kamp chnget "left"
    kpitch chnget "right"
    
    kamp portk kamp, 0.05 
    kpitch portk kpitch, 0.05    
    
    a1 oscil iamp * kamp, 100 * 16 ^ kpitch, gi_wave
    
    out a1
endin

</CsInstruments>
<CsScore>
i 1 0 [60 * 60 * 24] 0.707
</CsScore>
</CsoundSynthesizer>

trapped_instr.csd

;============================================================================;
;============================================================================;
;============================================================================;
;                                 Sand Instrument                            ;
;                                  Adapted from                              ;
;                            == TRAPPED IN CONVERT ==                        ;
;                                Richard Boulanger                           ;
;============================================================================;
;============================================================================;
;                                   ORCHESTRA                                ;
;============================================================================;
;============================================================================;
;============================================================================;
;                            written July 1979 in music11                    ;
;                          M.I.T. Experimental Music Studio                  ;
;                            revised June 1986 in Csound                     ;
;                                M.I.T. Media Lab                            ;
;                          revised July 1996 in SHARCsound                   ;
;                                Analog Devices Inc.                         ;
;============================================================================;
;============================================================================;
;============================================================================;

<CsoundSynthesizer>
<CsInstruments>
sr = 44100
kr = 4410
ksmps = 10
nchnls = 2
0dbfs = 1

garvb  init     0
gadel  init     0

chn_k "left", 1
chn_k "right", 1
chnset 0, "left"
chnset 0, "right"

        instr  9                             ; p4 = delay send factor
kamp    chnget "left"
kpitch  chnget "right"
    
kamp    portk  kamp, 0.05
kpitch  portk  kpitch, 0.05

kfreq =  30 * 4 ^ kpitch
ifreq   =      cpspch(p5)                    ; p5 = freq
                                             ; p6 = amp
k2      randh  p8, p9, .1                    ; p7 = reverb send factor
k3      randh  p8 * .98, p9 * .91, .2        ; p8 = rand amp
k4      randh  p8 * 1.2, p9 * .96, .3        ; p9 = rand freq
k5      randh  p8 * .9, p9 * 1.3

;kenv    linen  p6, p3 *.1, p3, p3 * .8
kenv = kamp * p6

a1      oscil  kenv, kfreq + k2, 1, .2
a2      oscil  kenv * .91, (kfreq + .004) + k3, 2, .3
a3      oscil  kenv * .85, (kfreq + .006) + k4, 3, .5
a4      oscil  kenv * .95, (kfreq + .009) + k5, 4, .8

amix    =      (a1 + a2 + a3 + a4)

        outs   (a1 + a3), (a2 + a4)
garvb   =      garvb + (amix * p7)
gadel   =      gadel + (amix * p4)
        endin
        
;============================================================================;
;==================================== SMEAR =================================;
;============================================================================;
        instr  98
asig    delay  gadel, .08
        outs   asig, asig
gadel   =      0
        endin
;============================================================================;
;==================================== SWIRL =================================;
;============================================================================;
       instr   99                            ; p4 = panrate
k1     oscil   .5, p4, 1
k2     =       .5 + k1
k3     =       1 - k2
asig   reverb  garvb, 2.1
       outs    asig * k2, (asig * k3) * (-1)
garvb  =       0
       endin
       
</CsInstruments>
<CsScore>
f1   0  8192  10   1
f2   0  512   10   10  8   0   6   0   4   0   1
f3   0  512   10   10  0   5   5   0   4   3   0   1
f4   0  2048  10   10  0   9   0   0   8   0   7   0  4  0  2  0  1

;i 1 0 [60 * 60 * 24] 0.707
i 9 0   [60 * 60 * 24]     0.4    4.113    0.2    0.2    6.2    320


i98  0      [60 * 60 * 24]
i99  0      [60 * 60 * 24]      0.0618
</CsScore>
</CsoundSynthesizer>