The electronics for this were pretty straightforward. The biggest issue with servo systems is to make sure the servos are powered from their own regulator- this will help isolate any electrical noise generated by the servos that would otherwise cause glitches in the servo movements. 

Holes were drilled in the Aluminum base plate for the speaker and for running wires up the cannon arm. I decided to attach the laser sight pod to the cannon body using a USB port so it would be easy to detach it for painting and shipping. The female port was added to the cannon body using some ProPoxy20 epoxy putty and the same was done with the male end in the laser sight.

The Luxeon LED was added to the inside of the cannon barrel using two standoffs and two SMT  LEDs were attached to the front of the Luxeon LED board. The wires for the LEDs and laser sight were then run along the inside of the cannon and they exited the canon just behind the upper arm end and then ran down the cannon arm. All of the electronics boards were then attached to the base plate using standoffs and a lower base plate was attached to the cannon base plate with three threaded Aluminum rods.