I had reason recently to take a look at the ATmega32U4 microcontroller again.  This is used on the Arduino Leonardo and the Sparkfun Pro Micro and includes built-in USB functionality.  But it also has four hardware timers, so I thought I'd try to get them working with the three-timer Tone library. https://youtu.be/N0GdLr4a9hM Warning! I strongly … Continue reading Arduino Four-tone Multi-tones →