How Do Knock Sensors Work? A knock sensor is typically a piezoelectric sensor mounted on the engine block or cylinder head. The sensor is designed to detect the high-frequency vibrations caused by ...

A knock sensor is important to a car's fuel efficiency. Learn more about what a knock sensor is, what it does, where it's located, and how it works.

We have seen piezo elements used in DIY speakers, sonar projects, and even as the sensor for an atomic force microscope, but we have yet to see a piezoelectric transformer in a hack.

A designer and a senior engineer analyze a low-cost alternative for solid-state general-purpose impact sensing uses a standard piezoelectric device (PZT) an a 555 timer.

This cross-section diagram of a Series 208 Quartz Force Sensor from PCB Piezotronics Inc. of Depew, N.Y., shows the basic assembly of a piezoelectric sensor.

The build here costs about $10 and uses an ATtiny45, piezo sensor, PS/2 connector, and a few other minor items. The end result is a switch that'll turn your computer on (or off) with a knock.