function setBrightness(addr, intensity) {
	    if(addr<0 || addr>=maxDevices)
			return;
	 	if (typeof intensity == 'undefined') return; 
		
		intensity = constrain(intensity, 0, 15); 
	    	
		spiTransfer(addr, OP_INTENSITY,intensity);

	}
function setBrightness(addr, intensity) {
	    if(addr<0 || addr>=maxDevices)
			return;
	 	if (typeof intensity == 'undefined') return; 
		
		intensity = constrain(intensity, 0, 15); 
	    	
		spiTransfer(addr, OP_INTENSITY,intensity);

	}
function setBrightness ( addr , intensity ) { if ( addr < 0 || addr >= maxDevices ) return ; if ( typeof intensity == 'undefined' ) return ; intensity = constrain ( intensity , 0 , 15 ) ; spiTransfer ( addr , OP_INTENSITY , intensity ) ; }
sets the brightness of the LEDs, 0 to 15
sets the brightness of the LEDs 0 to 15