A pen which includes a marking device, the pen being operative to mark a visible path onto a surface. The marking device is electronically controllable to change an attribute of the path, such as line width or color. The marking device is actuated in response to a compression force sensed by a switc...http://www.google.fr/patents/US7413363?utm_source=gb-gplus-shareBrevet US7413363 - Electronically controllable pen comprising a force switch
Electronically controllable pen comprising a force switch
