Mechanical sensor

sensors

1. Mechanical Sensor And Its Application Central University O f Jharkhand By farzi faraz

2. What is sensor ? A sensor is a converter that measures a physical quantity and converts it into a signal which can be read by an observer or by an instrument . Example a mercury in glass thermometer .

3. Three terms Transducer a device that converts a primary form of energy into a corresponding signal with a different energy forms. Sensor a device that detect or measures a signal. Actuator a device that generates a signal. real world actuator sensor intelligent feedback system

4. Mechanical Sensor Class of sensors to measure mechanical phenomena. Includes Pressure sensor Force and torque sensor Inertial sensor Flow sensor

5. Mechanical Sensing Techniques Piezoresistivity Piezoelectricity Capacitive techniques Inductive techniques Resonant techniques

6. Piezoresistivity Effect exhibited by various materials that exhibit a change in resistance due to an applied pressure. Strain Gauge Sensors that exhibit a change in resistance as a result of an applied strain are generally termed strain gauges. The strain gauge (SG) is glued to the element whose strain is to be measured When stress is applied, the element and the SG is deformed at the same manner Gauge factor is defined as Indicates how easy the strain can be measured Large GF means large change in resistance for a given strain Strain gauge

7. Piezoelectricity the property of producing an electric charge when subjected to an applied mechanical force. Effect arises because of the charge asymmetry within the crystal structure. Quartz and Rochelle salt are naturally occurring piezoelectric. Applied force Piezoelectric material

8. Capacitive Techniques The displacement measurement due to the change in capacitance. Capacitance There are 3 ways to change capacity variation of plate separation variation of plate area variation of dielectric constant

9. Inductive Techniques Inductance a motion of permeable core changes the inductance AC bridge can be used to detect the change in inductance

10. A resonator is a mechanical structure designed to vibrate at a particular resonant frequency . Resona nt Techniques Block Diagram

11. Pressure Sensor Pressure sensor is use to measure the pressure of fluid and gas in industrial application. Pressure is force per area that fluid exerts on its surroundings Static Pressure The fluid is not moving Dynamic Pressure The fluid is moving Principles Involves Are

12. Pressure sensor Pressure sensor types Absolute pressure sensor sensor measures the pressure relative to perfect vacuum. Gauge pressure sensor sensor measures the pressure relative to atmospheric pressure. Vacuum pressure sensor sensor that measures pressures below atmospheric pressure. Differential pressure sensor sensor measures the difference between two pressures

13. Force and torque sensor T he fundamental operating principles of force and torque sensor instrumentation are closely allied to the piezoelectric and strain gage devices used to measure static and dynamic pressures . Consider a simple sensor that is to be developed to measure a reaction force at the base of a spring, as shown below.

14. Force and torque sensor Torque is a measure of the forces that causes an object to rotate. Reaction torque sensors measure static torque with a stationary or non-rotating transducer. Rotary torque sensors use rotary transducers to measure torque.

15. Inertial Sensor Inertial sensor measures linear acceleration along one or several axis refered to as accelerometer. Sensor that measures angular acceleration along one or several axis are refered to as gyroscope. accelerometer gyroscope

16. Flow Sensor A flow sensor is a device for sensing the rate of flow of material. Material may be solid liquid or gas. Flow rate is measured by weighting the amount of material on a platform of length L

17. Application of different mechanical sensor Central University of Jharkhand

18. Application OF Pressure Sensor Manometer a traditional pressure sensor. Manometers can be used both as a gauge sensor with one side vented to atmosphere and as differential sensors with pressure applied to both legs . Pressure sensor are also use in aneroid barometer and bourdon tube. Microphones are a particular type of MEMS pressure sensor designed to transduce acoustic signals into electrical output. example hearing aid

19. U tube manometer Bourdon tube

20. Pressure sensor application in auto parts sensor Auto parts applications

21. Application of force and torque sensor A force-sensing resistor is a material whose resistance changes when a force or pressure is applied. They are also known as forcesensitive resistor. T orquemeter is a device for measuring and recording the torque on a rotating system, such as an engine, crankshaft, gearbox etc In control systems when motion feedback is employed. In process testing, monitoring and diagnostics applications. In measurement of power transmitted through a rotating device. In controlling complex non-linear mechanical systems .

22. torquemeter Force sensitive resister

23. Application of inertial sensor Accelerometer In industrial application, the design of accelerometer is based on Newton’s Law and Hooke’s Law of Spring Inertial sensors are used for military applications such as inertial guidance and smart ammunition . Accelerometers can be used to measure vibration on cars, machines, buildings, process control systems and safety installations .

24. accelerometer

25. Application of flow sensor flow sensors are based on sensors which measure the transfer of heat caused by the moving medium. This principle is common for microsensors to measure flow . Velocimetry Velocimetry is the measurement of the velocity of fluids. For measuring velocity and length on moving surfaces, laser surface velocimeters are used. velocimeter

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