1. import krister.Ess.*;
   
   AudioChannel myChannel;
   SineWave myWave;
   int frequency = 5000;
   int amplitude =50;
   int duration=5000; // 5 secs
   int timer =0;
   
   void setup() {
   size(500,250);
   background(0);
   frameRate(10);
   
   // start up Ess
   Ess.start(this);
   
   // create a new AudioChannel
   myChannel=new AudioChannel();
   myChannel.sampleRate(44100);
   
   // generate 3 seconds of a soft triangle wave
   
   // play
   //myChannel.play();
   }
   void draw() {
   // set the size to 5 seconds
   myChannel.initChannel(myChannel.frames(duration));
   
   myWave=new SineWave(frequency,0.5);
   myWave.generate(myChannel,0,myChannel.frames(3000));
   
   myChannel.play();
   stroke(255);
   beginShape();
   for(int j=0;j<myChannel.buffer.length;j++)
   {
   vertex((float)j/10,height/2+amplitude*myChannel.buffer[j]);
   }
   background(0);
   endShape();
   //print(amplitude);
   if(frameCount%10==0)
   {
   timer++;
   }
   // timer++;
   // println("time elapsed: "+timer+" ");
   //println("duration: " +duration);
   fill(0,200f,0);
   text("duration: "+ duration,15,30);
   text("frquency: "+ frequency,400,30);
   
   fill(220,0,0);
   text("elapsed time: "+ timer +" (s)",15,45);
   text("amplitude: "+ amplitude,400,45);
   if(timer*1000>= duration)
   {
   stop();
   }
   }
   // we are done, clean up Ess
   
   public void stop() {
   Ess.stop();
   super.stop();
   }
   void keyPressed()
   {
   if (key=='f')
   {
   if(mousePressed==true)
   {
   if (mouseButton==LEFT)
   frequency+=1000;
   else if(mouseButton==RIGHT)
   frequency-=1000;
   }
   }
   else if(key=='d')
   {
   if(mousePressed==true)
   {
   if (mouseButton==LEFT)
   duration+=1000;
   else if(mouseButton==RIGHT)
   duration-=1000;
   }
   }
   else if(key=='a')
   {
   if(mousePressed==true)
   {
   if (mouseButton==LEFT)
   amplitude+=10;
   else if(mouseButton==RIGHT)
   amplitude-=10;
   }
   }
     
   }

      Note: Ess library is needed for the code to work!!