About light
Trying to switch light ON/OFF  from sound feedback and connect light with the sound and the movements in a real-time processing effects, we used arduino to power the light spot’s cable via computer messages.
I hooked a 500W/ 220V light spot to arduino board by using a 9DV/10A relay. The tutorial for interfacing 220V light with arduino’s board 5V was taken from:http://www.glacialwanderer.com/hobbyrobotics/?p=9

Pockets for FM-transmitters
Those are old generation mobile pockets of a good size for the fm-transmitters. It is easier to be carried on the dancer’s costume.