A piezo buzzer is used to generate tones, beeps, and alerts. This giant piezo buzzer can generate a tone between 200Hz and 10KHz with a 3-30V peak to peak square wave. The loudest tones are generated around 3KHz. To use this buzzer, connect one pine to ground and the other through a 100ohm resistor to a microcontroller programmed to output a square wave or a timer IC.

Alternatively, this piezo can also be used to detect knocks or vibration by reading the voltage across the element.