I am trying to build a sketch where a webcam can be triggered on by using the audio: If the webcam records a audio volume of 'x' the webcam turns on. When it reaches this level again it will go off. 

I've already made such a sketch in Max MSP but I want to figure out how to make it in Processing, never worked with the program before so I am a complete stranger.

The code i've found was one which turned a webcam off after a mouseclick;

2. import processing.video.*; 
3. Capture cam; 
4.  
5. void setup() { 
6.   size(640, 480); 
7.   cam = new Capture(this);
8.   cam.start(); 
9. } 
10.  
11. void draw() { 
12.   if (cam.available()) { 
13.     // Reads the new frame
14.     cam.read(); 
15.   } 
16.   image(cam, 0, 0); 
17. } 
18. 
    
19. void mousePressed() {
20.   cam.stop();
21. }