A shieldable winged needle assembly includes a hub and a cannula projecting distally beyond the hub. This infrared interface is able to communicate with an infrared port on a local computer. According to the invention, each moving electrode, together with an adjacent fixed electrode, forms a capacitance which varies according to the position of the moving mass. In several disclosed examples, a broadcast video provisioning system switches unicast transmissions to broadcast transmissions based on the ranked list, based on this ranking and possibly on the available unicast and broadcast bandwidth.