A system includes a support, a pendular element, an elastic restraint, an image sensor, and a processing system. The elastic restraint couples the pendular element to the support and applies to the pendular element a restraining force that opposes movement of the pendular element in at least a first...http://www.google.de/patents/US7293459?utm_source=gb-gplus-sharePatent US7293459 - Image-based sensing of acceleration
