The smart glasses market is rapidly expanding, reaching a valuation of $1 billion in 2022. These devices integrate contextual awareness with AI algorithms, a combination that is expected to make smart glasses an essential everyday tool in the near future. However, achieving unobtrusiveness presents significant design challenges, particularly in integrating the required sensing interfaces into a compact form. CapGlasses tackles one key element of contextual sensing by recognizing facial expressions and head gestures of the wearer, while packaging this capability into a form suitable for smart glasses. Two key innovations can be highlighted here. First, the use of a transparent electrode enables a greater sensing surface without affecting the overall form factor. Second, an active electric field increases the sensitivity of the system while remaining safe for the wearer.