The KY-012 active piezo buzzer is a 3-pin module that creates an audible sound at 2.5 kHz without the need for pulse width modulation (PWM) or any additional complex code. The only requirement is to set the signal pin to HIGH. If you’re looking for a simple but effective way to build audio into an Electronics or Arduino project, the KY-012 Active Buzzer Module is a great choice, and is designed to simply produce a single-tone sound when the incoming signal is high. This allows for single-pin operation on an Arduino Board, which is perfect for building a custom alarm or detection system that can send out an audible signal when it receives the electronic high signal from the Arduino controller board.