Smart tangible displays in the everyday world: a haptic door knob

As embedded microprocessor intelligence penetrates ever deeper into the world, it is often accompanied and represented by user interfaces with limited control and display capabilities. One of the possibilities offered by haptic (force and tactile) feedback is a more direct and human mode of bidirectional information transfer: when well designed and situated it can provide an aesthetically satisfying as well as functional handle onto elements of the digital world. The paper describes the design of an experimental platform, "Aladdin", which integrates a haptic display into commonplace manual control, a doorknob. The system's mechatronic design includes a haptic knob with torque and thermal display, a high quality auditory display, and sensing and actuation of other door elements. Low-latency integration of the haptic and auditory displays, crafting of both the haptic and auditory content and retaining a high degree of control over auditory output were emphasized. Scenarios for the door's use are described, and results of preliminary experiments with our prototype are discussed.