Expanding the Vocabulary of Multitouch Input using Magnetic Fingerprints

We present magnetic fingerprints; an input technique for mobile touchscreen devices that uses a small magnet attached to a user's fingernail in order to differentiate between a normal touch and a magnetic touch. The polarity of the magnet can be used to create different magnetic fingerprints where this technique takes advantage of the rich vocabulary offered by the use of multitouch input. User studies investigate the accuracy of magnetic fingerprint recognition in relation to magnet size, number of magnetic fingerprints used; and size of the touchscreen. Studies found our technique to be limited to using up to two fingerprints non-simultaneously, while achieving a high classification accuracy (95%) but it nearly triples the number of distinguishable multi touch events. Potential useful applications of this technique are presented.