Make your own musical fun with a Retro Stylophone
The 555 timer IC is one of the most under-rated and yet widely-used analog ICs on the market, and quite frankly needs no introduction. Part of the 555's repertoire is that of a signal generator, and thus can be used to make music.
Xaver Schrems does just that with their Stylophone, a nod to 20th-century electronic music-making. They have devised a 555-based circuit along with an analog amplifier, which uses a custom PCB to emulate a typical organ from the era, as shown below:
Different 555 periods are activated with a stylus via the piano key-style pads on the PCB - a demonstration of which is replayed in the following video:
All the required circuitry and notes are provided, so for more information on how to make your stylophone, visit the detailed project page.