Hi,

I'm new to scripting but trying to complete an interactive installation in a stairwell.
I have two .pde that work separately and I'm trying to combine them into one .pde.  I'd like the first code (boxes) to run until an ultrasonic rangefinder triggers a reset (max/msp output a2_0<50)...at which point the second code (class Walkers) will fade in quickly, play for 6 seconds and fade back to the boxes.  
Here's my awkward attempt that gives me only a background color.  Can you please tell me where to start looking for a solution?  Am I waaayyy off?
Thanks!

//walkers derived from "randomwalkers"original code: http://www.codetree.org/artwork/art.php?id=176.  Author: ninoscript
//boxes derived from processing.org "FOV" example
import com.cycling74.io.*;
import com.cycling74.net.*;
import com.cycling74.util.*;
import maxlink.*;
import com.cycling74.msp.*;
import com.cycling74.max.*;
import com.cycling74.mxjedit.*;
MaxLink link = new MaxLink(this,"maxlink");
public float a0_0, a1_0, a1_5, a2_0, a2_5, camx1, camy1, camx2, camy2;

float box1 = 0.0;
float box2 = 0.0;
float box3 = 0.0;

int walkersNumber = 100;
Walker[] walkers = new Walker[walkersNumber];

void setup() {
   link.declareInlet("a0_0"); //ardBT#1 vibration sensor
   link.declareInlet("a1_0"); //ardBT#2 photoresistor
   link.declareInlet("a1_5"); //RESERVED
   link.declareInlet("a2_0");  //USB Arduino rangefinder
   link.declareInlet("a2_5"); //USB Arduino photoresistor
   link.declareInlet("camx1");  //lower landing camera
   link.declareInlet("camy1");  //lower landing camera
    link.declareInlet("camx2");  //upper landing camera
   link.declareInlet("camy2");  //upper landing camera
   
 size(1030, 2550, P3D);
 frameRate(30);
    if (a2_0 < 50) {
     frameRate(camx1/10);
     }
noStroke();

      if (a2_0 < 50) {
         for(int i=0; i<walkersNumber; i++){
         walkers[i] = new Walker(i);
        }
      }
}

void draw()
{
//lights();
 background(a2_5);//photoresistor from arduino usb#1
     if (a2_0 < 50) {
     background(51);
     }
 float cameraY = height/2.0;
 float fov = camy1/float(width) * PI/2; //float fov = camy/float(width) * PI/2
 float cameraZ = cameraY / tan(fov / 1.0);
 float aspect = float(width)/float(height);
 perspective(fov, aspect, cameraZ/5.0, cameraZ*5.0);
 
//BACK BOX
 box1 = 5;
 box2 = 50;
 box3 = 1000;
translate(width/2, 1400, 0);
rotateX(-camy1/3000);// rotateX(-PI/3 + camx/float(height) * PI);
rotateY(camx1/float(height)+45);//(PI/1 + camy/float(height) * PI/2);
 fill(255);
   //if (a2_0 < 50) {
  // fill(232,0,0);
   //  }
 box(box1,box2,box3);

///SIDE BOXES
  translate(-box3/2, 0, box3*.5);
  fill(255);
    //  if (a2_0 < 50) {
    //  fill(232,0,0);}
  box(box3,box2, 5);
 translate(0, 0, -box3);
 box(box3,box2,5);


      if (a2_0 < 50) {
        for(int i=0; i<walkersNumber; i++){
        walkers[i].walk();
        walkers[i].render();
        }
      }
}    
       
class Walker {
   int x, y, _color;
 
   Walker(int color_) {
     x = int(random(width));
     y = 0;
     _color = color_;
     }
 
   void render() {
     float rcolor = random(20, 50);
     stroke(0);
     stroke (rcolor*2,0,0);
    fill(camx1/3, 0, 0);
    // strokeWeight(2);
     ellipse (x,y,camx1/18,camx1/18);
     }

   void walk() {
     float vx = random(5)-2;
     float vy = random(5)-.5;
     x += vx;
     y += vy;
     x = constrain(x,0,width-1);
     y = constrain(y,0,height-1);
     }
     
}