Our goal was to develop a computer system trained to sense a user's emotional st ate via the recognition of physiological signals. In the course of developing a n exploratory pilot study toward this end, we encountered and addressed unique a nd context-dependent interface design and synchronization challenges. We used social science methods to induce a state of frustration in users, collected the physiological data, and developed an effective strategy for coupling these data with real-world events. Compressed Postscript . PDF . Full list of tech reports