US Patent 9898091 Virtual reality system with head-mounted display, camera and hand-held controllers

A virtual-reality system includes a head-mounted display (HMD), a forward-looking camera coupled to the HMD and a hand-held controller communicatively coupleable to the HMD. The hand-held controller includes a first user-input key, a grip, and an outward-facing surface coupled to the grip. The outward-facing surface includes a plurality of illumination sources which provide light that is detectable by the camera for sensing a position of the controller based on a user motion.