Method and apparatus for measuring acceleration or mechanical forces

A method for measuring acceleration or mechanical forces, said acceleration causing inertial forces,

• said method comprising:
• providing a transducer comprising:
• at least one piezoelectric element having a polarization axis;
• a supporting base;
• two arms or uprights placed on the supporting base, the two arms or uprights being deformable or tiltable in relation to the supporting base by a component of a mechanical or an inertial force acting substantially in a direction perpendicular to the polarization axis of the at least one piezoelectric element;
• each arm or upright of the two arms or uprights comprising a region of relatively reduced thickness acting as a hinge means and being located adjacent to the supporting base;
• and at least two spaced surfaces, the at least one piezoelectric element being mounted in between the at least two spaced surfaces, each of the at least two spaced surfaces being part of one of the two arms or uprights, and the at least two spaced surfaces being arranged so that they are mutually displaceable by the force component;
• providing inertial forces or mechanical forces, said inertial forces being caused by acceleration, said forces having a first component being substantially perpendicular to the polarization axis of the at least one piezoelectric element;
• deforming or tilting the two arms or uprights in relation to the supporting base so as to mutually displace the at least two spaced surfaces and so as to create, in the at least one piezoelectric element, a shearing force substantially parallel to its polarization axis;
• and
• outputting a first electrical signal across a first pair of substantially parallel surfaces of the at least one piezoelectric element, said first output signal representing a measure of said first mechanical or inertial force component.