This paper introduces MagPen, a magnetically driven pen
interface that works both on and around mobile devices.
The proposed device is accompanied by a new vocabulary
of gestures and techniques that increase the expressiveness
of the standard capacitive stylus. These techniques are: 1)
detecting the orientation that the stylus is pointing to, 2)
selecting colors using locations beyond screen boundaries,
3) recognizing different spinning gestures associated with
different actions, 4) inferring the pressure being applied to
the pen, and 5) identifying various pens associated with
different operational modes. These techniques are achieved
using commonly available smartphones that sense and
analyze the magnetic field produced by a permanent magnet
embedded in a standard capacitive stylus. This paper
explores how magnets can be used to expand the design
space of current pen interaction, and proposes a new
technology to achieve such results