An apparatus for an imbalance test includes a strain measurement module that measures a strain voltage across terminals of a strain gauge. The strain voltage is representative of an amount of force on the strain gauge. The apparatus includes a test measurement module that measures a test voltage across the terminals of the strain gauge while a test resistor is connected in parallel with a resistor of the strain gauge. The test resistor is connected while the test measurement module measures the test voltage and is disconnected while the strain module measures strain voltage. The apparatus includes an average module that calculates an average strain voltage from two strain voltage measurements. The strain voltages are measured preceding and after the test voltage measurement. The apparatus includes a difference module that determines a difference voltage. The difference voltage is a difference between the average strain voltage and the test voltage.

A portable test instrument for a rivet nut setting tool is disclosed, and the portable test instrument includes a shell body, a circuit module disposed in the shell body, and a strain gauge having a part located in the shell body and electrically connected to the circuit module, and a display device. An end of the strain gauge is exposed to the shell body and used to mount with the rivet nut setting tool. The strain gauge can change a value of a signal transmitted to the circuit module when being forced to deform. The display device is disposed on the shell body and electrically connected to the circuit module, and configured to display data measured by the strain gauge.

A pressing force sensor that includes a sensor element configured with a piezoelectric film, a lead terminal for connection to an external circuit, a wiring conductor which connects pressing force detection electrodes and the lead terminal, and a flexible printed circuit board which withstands solder reflow temperatures. The flexible printed circuit board has the pressing force detection electrodes formed on a first principal surface thereof, and is folded via a folding line while the first principal surface faces inward. The sensor element is deflected by a pressing force applied to a second principal surface which faces outward and is in a first area of the flexible printed circuit board which is on one side with respect to the folding line, and a signal corresponding to the pressing force is thus taken out from the pressing force detection electrodes.

Fully-passive sensor systems that receive an input electromagnetic signal and return an output electromagnetic signal are described. The sensor systems can be used to measure pressure in biological or non-biological systems.

A display apparatus includes a substrate including a first area, a second area, and a bending area, the bending area disposed between the first area and the second area and bending about a bending axis running along a first direction; a first piezoelectric device disposed over the bending area; and a pressure sensor. The first piezoelectric device is configured to contract or expand according to a pressure variation sensed by the pressure sensor.

A force sensor includes a first structure, four strain generation parts, and a second structure. The first structure is formed in such a way that a third axis penetrates therethrough. The four strain generation parts are provided along first and second axes on a reference plane formed by the first and second axes. The second structure is connected to the first structure with the strain generation parts interposed therebetween. The strain generation parts each includes a first beam part extending along the first axis or the second axis, and a second beam part extending in a direction orthogonal to the first beam part and connected to the first beam part at an intermediate part. The strain generation parts are formed in such a way that they are line-symmetric with respect to both the first axis and the second axis when projected in a direction of the third axis.

A digital sensor for pre-warning of multistage breakage-triggered deformation threshold includes first tension rods, second tension rods, a radio-frequency identification (RFID) chip, and a brittle fracture module, where the first tension rods as well as the second tension rods are respectively fixedly connected to two points to be measured on a tension member, and the first tension rods and the second tension rods can move reversely with deformation of the tension members; the RFID chip is fixedly arranged on the first tension rods; the brittle fracture module includes a bottom plate and a plurality of resistors, where two ends of the bottom plate are fixed to the first tension rods and the second tension rods, and the plurality of resistors forming a lumped parallel circuit are parallelly arranged on the bottom plate; the RFID chip is connected to two ends of the lumped parallel circuit.

Systems and methods for evaluating the performance of an athlete using a strain gauge is described. In some embodiments, the measurement system comprises a strain gauge and a central processing device. The strain gauge can include a power source, an inertial measurement unit (“IMU”) comprising a load cell, a microcontroller, and a wireless communication module. The strain gauge can be configured to output strain data at a rate of at least 1 kHz and the central processing device can be configured to receive the strain data transmitted from the wireless communication module.

A device for measuring mechanical changes includes at least one first resistor which is designed to convert a mechanical change into a change of its resistance value and at least one operational amplifier, wherein the at least first resistor and the operational amplifier are connected such that the at least first resistor serves as input resistance for the operational amplifier and the operational amplifier provides or can provide a measurement result at an output. The first resistor is for example a strain gauge that can be secured to a component.

A sensor includes a plurality of piezoresistive elements and a plurality of electrical connection terminals. The plurality of piezoresistive elements are fabricated on a first side of a substrate. A second side of the substrate is configured to be coupled to an object where a physical disturbance is to be detected. A plurality of electrical connection terminals are coupled to the first side of the substrate.