Displacement measurement is the measurement of changes in directed distance (displacement). Devices measuring displacement are based on displacement sensors, which can be contacting or non-contacting.[1] Some displacement sensors are based on displacement transducers,[2] devices which convert displacement into another form of energy.[3]
Displacement sensors can be used to indirectly measure a number of other quantities, including deformation, distortion, thermal expansion, thickness (normally through the combination of two sensors), vibration, spindle motion, fluid level, strain and mechanical shock.[1]
Displacement sensors exist that can measure displacement on the order of nanometers or smaller.[1]
Application
Displacement receivers can be used to study and observe the stress waves passing through a material after it is struck.[4] This can be used to assess fire damage to reinforced concrete.[4]
Displacement transducers are often used to measure vibration.[5]
Types
Optical displacement sensors exist, using reflected light to determine distance.[6]
An ultrasonic displacement sensor is a kind of displacement sensor.[6] These measure the distance to targets by emitting low-frequency sound waves and measuring the time they take to return.[6]
Strain gauges can be used as the base for small displacement transducers on the order of 0 to 10 mm.[7]
In music, certain music keyboards can be considered to measure displacement in the sense that they respond to displacement, rather than velocity (as is more commonly the case).[citation needed]
Examples of displacement-responding sensors include the mechanical action of trackerorgans, as well as the force-sensing resistors found in music keyboards that had polyphonic aftertouch capability. Polyphonic aftertouch is no longer a feature of presently manufactured keyboards, but certain older models such as the Roland A50 featured a pressure sensing resistor, similar in principle-of-operation to a carbon microphone, in each key.[citation needed]
References
^ abcLeach, Richard (2014-01-01), Leach, Richard (ed.), "Chapter 5 - Displacement Measurement", Fundamental Principles of Engineering Nanometrology (Second Edition), Micro and Nano Technologies, Oxford: William Andrew Publishing, pp. 95–132, ISBN978-1-4557-7753-2, retrieved 2024-12-04, At the heart of all instruments that measure a change in length, or coordinates, are displacement sensors. ... Displacement sensors can be contacting or non-contacting, and often can be configured to measure velocity and acceleration.
^Mendelson, Yitzhak (2012-01-01), Enderle, John D.; Bronzino, Joseph D. (eds.), "Chapter 10 - Biomedical Sensors", Introduction to Biomedical Engineering (Third Edition), Biomedical Engineering, Boston: Academic Press, pp. 609–666, ISBN978-0-12-374979-6, retrieved 2024-12-04, Displacement transducers are typically used to measure physical changes in the position of an object or medium.
