Aspects of the subject technology relate to a sensor for a downhole tool. The downhole tool can include a collar and a sensor. The sensor can be secured to the collar for measuring one or more operational characteristics of the downhole tool during operation of the downhole tool. The sensor can include a substrate. The sensor can also include a plurality of strain gauges disposed on the substrate. The plurality of strain gauges can be configured to measure axial strains and torsional strains on the collar for measuring the one or more operational characteristics of the downhole tool.

Aspects of the subject technology relate to a sensor for a downhole tool. The downhole tool can include a collar and a sensor. The sensor can be secured to the collar for measuring one or more operational characteristics of the downhole tool during operation of the downhole tool. The sensor can include a substrate. The sensor can also include a plurality of strain gauges disposed on the substrate. The plurality of strain gauges can be configured to measure axial strains and torsional strains on the collar for measuring the one or more operational characteristics of the downhole tool.

A stress distribution measurement device includes: a first magnetostrictive sensor and a second magnetostrictive sensor each including an excitation coil that excites AC magnetism in a measurement target using alternating current, and a detection coil to which alternating current is induced due to the AC magnetism flowing in the measurement target; an excitation circuit that applies a first excitation voltage to the excitation coil of the first magnetostrictive sensor and applies a second excitation voltage to the excitation coil of the second magnetostrictive sensor, the second excitation voltage having a phase or a waveform different from the first excitation voltage; and a detection circuit that includes a first detector that performs synchronous detection of current flowing in the detection coil of the first magnetostrictive sensor based on the first excitation voltage and a second detector that performs synchronous detection of current flowing in the detection coil of the second magnetostrictive sensor based on the second excitation voltage.

A pressure sensitive pad configured to be placed under a mattress and configured to identify presence and absence of a threshold weight on the mattress. The pressure sensitive pad comprises a signal generator, a sensing zone, at least one variable matching resistor, a microcontroller unit (MCU). The signal generator configured to generate an electrical signal. The sensing zone has a sensing resistor with a first resistance which varies depending on a pressure applied on sensing zone. The variable matching resistor is in series with the sensing resistor and the signal generator, the variable matching resistor having a second resistance. The MCU has an analog-to-digital converter (ADC) configured for receiving and measuring a portion of the signal at an electrical junction between the sensing resistor an the at least one variable matching resistor, the MCU being configured to control the second resistance of the at least one variable matching resistor.

A pressure sensitive pad configured to be placed under a mattress and configured to identify presence and absence of a threshold weight on the mattress. The pressure sensitive pad comprises a signal generator, a sensing zone, at least one variable matching resistor, a microcontroller unit (MCU). The signal generator configured to generate an electrical signal. The sensing zone has a sensing resistor with a first resistance which varies depending on a pressure applied on sensing zone. The variable matching resistor is in series with the sensing resistor and the signal generator, the variable matching resistor having a second resistance. The MCU has an analog-to-digital converter (ADC) configured for receiving and measuring a portion of the signal at an electrical junction between the sensing resistor an the at least one variable matching resistor, the MCU being configured to control the second resistance of the at least one variable matching resistor.

A posture detection system for detecting a user's posture according to the embodiments includes a pressure sensor unit, a controller, a feedback mechanism, and a display unit. The pressure sensor unit has a sheet shape or a padded shape and includes plurality of sensors. Each of the sensors is configured to detect a pressure applied from the user. The controller is configured to classify the user's posture based on detection data detected by the pressure sensor unit. The feedback mechanism is configured to provide feedback to the user by vibrating based on a result of the classification. The display unit is configured to perform a display according to the result of the classification.

To improve the output signal quality of a load measurement by means of active magnetization, the invention provides a load measurement method for measuring a mechanical load on a test object (14), comprising: a) generating and applying a magnetic field to the test object (14); b) detecting a magnetic field changed by the test object (14) as a result of a mechanical load on the test object (14) by means of a first magnetic field detection device (20) to generate a first measurement signal (U1, UAB), c) detecting a magnetic field changed by the test object (14) as a result of a mechanical load on the test object (14) by means of a second magnetic field detection device (22) to generate a second measurement signal (U1, UAB), d) computationally determining a third measurement signal (UBT) from the first measurement signal (U1, UAB) and the second measurement signal (U2, UAT), and preferably comprising the steps of e) forming a difference from one (U2, UAT) of the first and the second measurement signals and the computationally determined third measurement signal (UBT) to produce an output signal, f) determining the mechanical load applied to the test object (14) based on the output signal. The invention also provides a corresponding load measurement device for carrying out the load measurement method.

An aspect of some embodiments of the present invention relates to a system configured for detecting connection between a pressure pad and a monitor. The system includes a pressure detection circuit and a presence detection circuit. The pressure detection circuit is configured for sensing whether the pressure on the pad is above or below the threshold pressure. The presence detection circuit is configured for determining whether a connection between the monitor and the pad is intact. The presence detection circuit is configured to establish a high voltage condition that occurs when connection is broken along the presence detection circuit and a low voltage condition when the presence detection circuit is intact.

An aspect of some embodiments of the present invention relates to a system configured for detecting connection between a pressure pad and a monitor. The system includes a pressure detection circuit and a presence detection circuit. The pressure detection circuit is configured for sensing whether the pressure on the pad is above or below the threshold pressure. The presence detection circuit is configured for determining whether a connection between the monitor and the pad is intact. The presence detection circuit is configured to establish a high voltage condition that occurs when connection is broken along the presence detection circuit and a low voltage condition when the presence detection circuit is intact.

Devices, systems and methods for calibrating a deformable sensor are disclosed herein. A calibration device for calibrating a deformable sensor includes a frame, at least one actuator supported by the frame, where the at least one actuator comprises a drive mechanism operatively coupled to a probe portion, and an electronic control unit communicatively coupled to the drive mechanism of the at least one actuator. The electronic control unit is configured to cause the drive mechanism to move the probe portion a predetermined position to form a predetermined contact surface defined by an end of the probe portion of the actuator.