Minimal material ear sensor system

The technology involves scaffold structures used for in-ear sensor systems. Such systems that can perform biometric signal detection or act as a human-computer interface. Scaffolding arrangements minimize the amount of material placed in the ear while providing a secure fitting device that can be worn for hours, days or longer in order to provide maximal benefit to the wearer. The scaffolding includes a "C"-shaped arcuate curvature for at least part of the housing. This configuration can act as a natural leaf spring to help maintain the housing in contact with different points along the ear. Sensors are located along various points of the scaffolding for use in different diagnostic situations. Different components of an on-board sensor input and processing system can be distributed along different parts of the scaffolding. Such structures beneficially minimize ambient sound occlusion and avoid the need of an exterior strap or clip worn around the ear.