Displacement detection device for a portable apparatus

[0045]FIG. 5 is a schematic illustration of a portable apparatus 28 provided with a displacement detection device 30 and with a microprocessor 31 in accordance with one embodiment of the invention. The displacement detection device 30 includes an accelerometer 32 of a linear type, and a processing circuit 34. In particular, the accelerometer 32 and the processing circuit 34 are integrated in a single chip.

[0046] The accelerometer 32 is of a known type. In one embodiment, it is a MEMS device made with the semiconductor technology and has three axes of detection x, y and z so as to generate three acceleration signals Ax, Ay and Az. Each acceleration signal is correlated to the acceleration detected along a respective axis of detection. For example, the accelerometer 32 can be realized as described in “3-axis digital output accelerometer for future automotive applications”, B. Vigna, et al., AMAA 2004.

[0047] The processing circuit 34 receives at input the acceleration signals Ax, Ay and