ActivityMonitor = {
	period : 0,
	seconds : 5,  //one minute = 60 seconds, 20 minutes = 1200 seconds

	init: function () { 
		ActivityMonitor.begin();
		$(document).mousemove(function(e){
			ActivityMonitor.reset_timer();
		});
	},
	
	begin: function () {
		ActivityMonitor.reset_timer();
		setInterval ( "ActivityMonitor.check()", 1000 );
	},

	check: function () {
				ActivityMonitor.period++;
				if ( this.period >= this.seconds ){	
					Posters.highlight_random_poster();
					ActivityMonitor.reset_timer();
				}	 
	},
				
	reset_timer: function() {
		ActivityMonitor.period = 0;
	}
}