The Many Applications of Piezoelectricity and Crystal Power

Unlike its pseudoscientific cousin of crystal power, the piezoelectric effect is the property that some crystals possess to generate power when they are deformed or stressed. There is also a converse effect that will make crystals deform when a current is passed through them. The ability of crystals to behave this way means that many different applications can be performed especially when precise movement or precise movement sensing is required.

Quartz Clocks

A quartz clock uses a quartz crystal that oscillates from electric current to provide a marker of time. The quartz crystal has an exact natural frequency that is determined by the size and shape of the crystal. The piezoelectric effect is used in both directions (both vibration from current, and current from vibration) to create an exact frequency of electrical current to drive the timing circuit. The same idea is used in computer clocks, which undergo frequency multiplication to reach a higher frequency.
Shock Absorption and Noise Reduction
Vibrations and noise can be used to provide power to systems, and in turn generate small amounts of electricity. Ideas such as dancefloors and high foot traffic areas being set up with crystals to harvest energy have been considered. Also it would be possible to soundproof walls using piezoelectric setups.
Motors
Piezoelectrics can be used to create some high precision motors such as the ones used in Single Lens Reflex Cameras and Inchworm motors than can be used for very precise surgical applications. The vibration of a crystal can be used to drive an actuator and hence very slow but exact motion is possible. The actuators can also be used as fuel injectors for high performance diesel engines.
Ignitors
The electric cigarette lighter runs of the idea of a hammer striking a piezoelectric crystal. This creates a high voltage which is passed over a small gap creating a spark. The same technology is used in the fuse on certain military ordnances such as rocket propelled grenades. A spark can be used to detonate the explosive payload.
Inkjet Printers
Crystal Vibrations are used in inkjet printers to force ink through a small jet and onto the paper. This is not true of all inkjet printers, as Canon’s Bubblejet printer actually relied on heat to force ink through the head and onto the page. The overwhelming majority of modern inkjet printers run on the piezoelectric effect.
Guitar Pickups
A small disk microphone is used to pick up vibrations from an acoustic guitar when playing over loudspeakers. The crystals simply vibrate to create voltages and this can be converted into an electrical signal for amplification.