A displacement sensor having a rectangular shaped elastic member. A piezoelectric element is attached to a first main face of the elastic member. The piezoelectric element has a rectangular-shaped piezoelectric sheet and electrodes on both main faces of the piezoelectric sheet. The piezoelectric sheet is made of poly-L-lactic acid and is at least uniaxially-stretched. The piezoelectric element is attached so that the uniaxial-stretching direction of the piezoelectric sheet is 45 relative to a long-side direction of the elastic member. When the elastic member is bent along the long-side direction, the piezoelectric sheet is stretched along the long-side direction, and the piezoelectric element generates voltage of predetermined level.

A muscle activity observation apparatus that includes a sensor module and a detection module. The sensor module includes a piezoelectric sensor. Moreover, the piezoelectric sensor has an output that changes in accordance with a tremor of a tendon or a muscle, and an output that changes in accordance with contraction and relaxation of the tendon or the muscle. A detector of the detection module detects an activity state of the tendon or the muscle using a tremor signal and a contraction-relaxation signal output from the piezoelectric sensor.

A displacement sensor having a rectangular shaped elastic member. A piezoelectric element is attached to a first main face of the elastic member. The piezoelectric element has a rectangular-shaped piezoelectric sheet and electrodes on both main faces of the piezoelectric sheet. The piezoelectric sheet is made of poly-L-lactic acid and is at least uniaxially-stretched. The piezoelectric element is attached so that the uniaxial-stretching direction of the piezoelectric sheet is 45 relative to a long-side direction of the elastic member. When the elastic member is bent along the long-side direction, the piezoelectric sheet is stretched along the long-side direction, and the piezoelectric element generates voltage of predetermined level.

A displacement sensor having a rectangular shaped elastic member. A piezoelectric element is attached to a first main face of the elastic member. The piezoelectric element has a rectangular-shaped piezoelectric sheet and electrodes on both main faces of the piezoelectric sheet. The piezoelectric sheet is made of poly-L-lactic acid and is at least uniaxially-stretched. The piezoelectric element is attached so that the uniaxial-stretching direction of the piezoelectric sheet is 45 relative to a long-side direction of the elastic member. When the elastic member is bent along the long-side direction, the piezoelectric sheet is stretched along the long-side direction, and the piezoelectric element generates voltage of predetermined level.

A displacement sensor having a rectangular shaped elastic member. A piezoelectric element is attached to a first main face of the elastic member. The piezoelectric element has a rectangular-shaped piezoelectric sheet and electrodes on both main faces of the piezoelectric sheet. The piezoelectric sheet is made of poly-L-lactic acid and is at least uniaxially-stretched. The piezoelectric element is attached so that the uniaxial-stretching direction of the piezoelectric sheet is 45 relative to a long-side direction of the elastic member. When the elastic member is bent along the long-side direction, the piezoelectric sheet is stretched along the long-side direction, and the piezoelectric element generates voltage of predetermined level.

A method for dynamic error compensation of a position sensor and a position sensor are disclosed. In the method, a calculated speed of a moving target for a current determined position is compared to a calculated running average of the speed of the moving target over a certain number of determined positions and if the calculated speed of the moving target for the current position is within a first window around the calculated running average of the speed of the moving target over the certain number of determined positions the dynamic angle error is not re-calculated for the current determined position, and/or if the calculated speed of the moving target for the current determined position exceeds a second window the previously calculated running average is deleted and the calculation of the running average of the speed of the moving target over a certain number of determined positions is restarted.

A system for operating a physical measuring chain includes a plurality of physical measuring components at a measuring location. Each of the physical measuring components includes at least one physical sensor, at least one physical transmission means and at least one physical evaluation unit. An identification code is detected of each physical measuring component, and a data network transmits detected identification codes to a data processing unit located remote from the measuring location. The data processing unit includes at least one software and measuring component data. The software reads out measuring component data for transmitted identification codes and thereby generates a digital measuring chain including at least one digital sensor, at least one digital transmission means and at least one digital evaluation unit and the data network transmits the digital measuring chain to a computer unit at the measuring location.

A passive magneto-electric transducer includes a piezoelectric layer and magnetic structures attached thereto with high permeability material. Strain can be generated between the structures on the piezoelectric layer when subjected to an external magnetic field. The piezoelectric layer is configured to generate charges as a response to its mechanical strain from the forces of the magnetic structures. At least one pair of electrodes is positioned to collect charges of opposite sign, generated by the piezoelectric layer, so that a signal can be provided by the transducer without external electrical power sources.