Arduino is a great way for today’s novices to start to ... Digital (pwm) pin D3 drives the piezo-buzzer through a PNP transistor, and the analog pin A0 takes care of the 10K trimpot. Analog pin A4 is ...

It runs on mains power and uses a 100dB piezo buzzer for ear-splitting effectiveness to alert [Adam] whenever the freezer is at 32°F/0°C or above. If the Arduino loses sight of the DHT22 ...

Although piezoelectric buzzers generate sound waves when you apply an ac voltage, you can use them in the opposite way: You obtain the maximum ac peak voltage that the piezoelectric buzzer generates ...

Tapping a piezo buzzer gives an interesting waveform, with a voltage spike followed by an envelope, and then a negative rebound voltage. It’s something [Igor Brichkov] is using, to make a simple ...