  Magnetic skyrmions are topologically stabilized quasi-particles and are
promising candidates for energy-efficient applications, such as storage but
also logic and sensing. Here we present a new concept for a multi-turn
sensor-counter device based on skyrmions, where the number of sensed rotations
is encoded in the number of nucleated skyrmions. The skyrmion-boundary force in
the confined geometry of the device in combination with the topology-dependent
dynamics leads to the effect of automotion for certain geometries. For our
case, we describe and investigate this effect with micromagnetic simulations
and the coarse-grained Thiele equation in a triangular geometry with an
attached reservoir as part of the sensor-counter device.
