A displacement receiver is a device that responds to or is sensitive to directed distance (displacement).

Examples of displacement receivers include carbon microphone

Carbon microphone

The carbon microphone, also known as a carbon button microphone or a carbon transmitter, is a sound-to-electrical signal transducer consisting of two metal plates separated by granules of carbon. One plate faces outward and acts as a diaphragm...

s, strain gauge

Strain gauge

A strain gauge is a device used to measure the strain of an object. Invented by Edward E. Simmons and Arthur C. Ruge in 1938, the most common type of strain gauge consists of an insulating flexible backing which supports a metallic foil pattern. The gauge is attached to the object by a suitable...

s, and pressure sensor

Pressure sensor

A pressure sensor measures pressure, typically of gases or liquids. Pressure is an expression of the force required to stop a fluid from expanding, and is usually stated in terms of force per unit area. A pressure sensor usually acts as a transducer; it generates a signal as a function of the...

s or force sensors, which, to within an appropriate scale factor, respond to distance.

In music, certain music keyboards can be considered displacement receivers in the sense that they respond to displacement, rather than velocity (as is more commonly the case).

Examples of displacement-responding sensors include the mechanical action of tracker

Tracker action

Tracker action is a term used in reference to pipe organs and steam calliopes to indicate a mechanical linkage between keys or pedals pressed by the organist and the valve that allows air to flow into pipe of the corresponding note...

 organs

Pipe organ

The pipe organ is a musical instrument that produces sound by driving pressurized air through pipes selected via a keyboard. Because each organ pipe produces a single pitch, the pipes are provided in sets called ranks, each of which has a common timbre and volume throughout the keyboard compass...

, as well as the force-sensing resistors found in music keyboards

Musical keyboard

A musical keyboard is the set of adjacent depressible levers or keys on a musical instrument, particularly the piano. Keyboards typically contain keys for playing the twelve notes of the Western musical scale, with a combination of larger, longer keys and smaller, shorter keys that repeats at the...

 that had polyphonic aftertouch capability. Polyphonic aftertouch is no longer a feature of presently manufactured keyboards, but certain older models such as the Roland

Roland Corporation

is a Japanese manufacturer of electronic musical instruments, electronic equipment and software. It was founded by Ikutaro Kakehashi in Osaka on April 18, 1972, with ¥33 million in capital. In 2005 Roland's headquarters relocated to Hamamatsu in Shizuoka Prefecture. Today it has factories in Japan,...

A50 featured a pressure sensing resistor, similar in principle-of-operation to a carbon microphone, in each key.