Some notes on PWM on the Raspberry Pi
I was recently working on a project in which I wanted to drive a simple piezo buzzer attached to a GPIO pin on a Raspberry Pi. I was already using the RPi.GPIO module in my project so that seemed like a logical place to start, but I ran into a few issues. You drive a piezo buzzer by generating a PWM signal with the appropriate frequency. The RPi.GPIO module implements PWM via software, which is tricky on a non-realtime system.