The miniature pressure transducer or MPT is cleverly designed to minimize sensor size while maintaining usable bandwidth. A foil strain gauge is coupled to a flat support plate, which is then mounted to the edges of a dome-like cover. When pressure is applied to the MPT, the support plate deforms, elongating the strain gauge (Burdea 1996).

While FSRs come in packages with a diameter as small as 7.1 mm, the necessity of a tail that is relatively fragile and bulky limits their usefulness when volume intrusion must be minimized. Precision Measurement currently manufactures two sizes of MPT that may be suitable for musical applications. One has a diameter of 2.7 mm and is 0.5 mm thick. The other has 1.5 mm diameter and is 0.3 mm thick. Thus these sensors may also be able to be integrated into acoustic instruments for measurement or control augmentation with relatively little effect on normal playing.

Because the MPT is based on the output of a strain gauge, it should be connected to a Wheatstone bridge circuit. The deformation of the gauge causes an increase in electrical resistance, which can be measured as a voltage by an operational amplifier (Burdea 1996).

• G. Burdea, Force and Touch Feedback for Virtual Reality. New York, NY: Wiley, 1996.
• Precision Measurement Co., 2005, Pressure Transducers – Miniature Series. http://www.pmctransducers.com/tranducers.html