UPDATE: this is an older guide designed for boards like the Arduino Uno and Adafruit METRO 328. It relies on assembly language code that’s specific to 8-bit AVR microcontrollers and will not work with boards based on other chips (ESP32, RP2040, SAMD, etc.).
Here’s an easy-to-build project that really packs a lot of blinkenlight for the effort: a little pocket-size music visualizer we call “Piccolo.”
Set Piccolo next to the telly or some speakers and you’ll see the lights respond to music and sound — lowest notes toward the left end of the graph, highest notes toward the right.
Technically this would be called a “spectrum analyzer,” but as this is not a precision scientific instrument, we’re more comfortable labeling it a “visualizer.” It’s strictly for show.
This intermediate Arduino project shows a clear progression from input to processing and then output in a package that’s appealing and easy for minds to grasp: music and lights. It’s not abstract or “science-y” unless you choose to peel back the layers…