An electronic device is disclosed, the device comprising a first portion, a hinge element disposed between the first portion and the second portion so that the first portion is rotatable with respect to the second portion, and a non-extensible element disposed between the first portion and the second portion, wherein the non-extensible element comprises a movable portion configured so that a rotation of the first portion with respect to the second portion causes motion of the movable portion with respect to the first portion. The electronic device further comprises a sensor arrangement disposed on the first portion, the sensor arrangement being configured to detect the motion of the movable portion, at least one processor, and at least one memory comprising computer program code configured to calculate an angle of fold between the first and second portion based on the motion of the movable portion as detected by the sensor arrangement.