[Dan] achieves that by using a normal piezo disk. These disks are used as speakers and buzzers in everything from smoke detectors to greeting cards, so they’re common and cheap. [Dan] cut his ...

However, [Billy] figured out a way to build them on the cheap. The build starts with a common piezoelectric buzzer. It’s torn down and the extraneous circuitry inside is removed. The piezo ...

Piezoelectric crystals are a class of materials that exhibit a unique property called piezoelectricity. These crystals generate an electrical charge when subjected to mechanical stress or strain, and ...