ESP32-S3 Music Sequencer Doubles as a Slap Bracelet

Every so often a project comes along that is less about the specification sheet and more about the fact that somebody committed completely to a bit. [3DSage]'s wearable ESP32-S3 music sequencer, featured on Hackaday on August 15, is one of those — a translucent, Y2K-styled sequencer that converts into a slap bracelet.

• Built on an ESP32-S3 with a built-in display, powered by a 666 mWh 3.7V lithium cell
• Note input via an array of brass rods, played stylophone-style
• Translucent PETG case printed hot and slow, then clear-enamel coated
• Band is a measuring-tape core wrapped in clear tape, giving it slap-bracelet action

What Hardware Is Inside?

The core is an ESP32-S3 board with an integrated display — the same class of part behind a lot of the compact projects we have covered lately, including the EITWatch gesture-sensing smartwatch. Control comes from a rotary encoder as the primary input plus a secondary button, and audio exits through a phono jack with automatic speaker/headphone switching.

Note entry is the charming part. Rather than buttons, the build uses an array of brass rods played with a stylus in the manner of a stylophone — a 1960s instrument choice that pairs oddly well with the deliberate early-2000s visual styling.

How Was the Translucent Case Made?

This is where the build gets genuinely instructive. The case is 3D printed in PETG with the maker's summarized rule of thumb: hot, slow, and don't cross the streams. For a case to read as truly translucent rather than cloudy, every layer has to line up with the one above it, which means tight tuning of temperature, speed, and travel moves. A clear enamel coat afterward fills in the remaining surface scatter.

The wearability trick is equally low-tech and equally satisfying: a measuring-tape core wrapped in clear tape, which gives the band its snap-to-wrist behavior. It is the kind of solution that costs almost nothing and works better than a designed-from-scratch hinge would have.

Why Projects Like This Matter

There is a real engineering lesson buried in the aesthetics. Getting optically clear PETG prints is a genuinely difficult calibration problem, and documenting the parameters that achieve it is more broadly useful than the sequencer itself. The build video runs roughly nine minutes on construction before moving to a demonstration, which makes it a usable reference for anyone chasing transparent enclosures.

It also sits in a growing category of ESP32-S3 wearables and handhelds that treat the microcontroller as a complete computing platform rather than a sensor node — a shift visible across our mini computer and maker coverage, from e-paper displays to local LLM experiments on the same silicon.

Sources: Hackaday — August 15, 2026; 3DSage on YouTube — August 2026.