An occlusion for use in a peristaltic pump includes independently movable occlusion fingers. Each transceiver has a directional antenna positioned in a substantially circular array to communicate signals with a plurality of stations in a corresponding sector. The plurality of images are analyzed using at least one second computer connected via a network. The lens is capable of dynamically changing at least one lens property of the lens. The ballast circuit preferably includes a current limit circuit that is inductively coupled to the resonant tank circuit.