Cardputer MIDI — Field Manual

Documentation for a wireless BLE MIDI instrument built on the M5Stack Cardputer ADV.

Read it: https://zsahs84.github.io/cardputer-midi-manual/

Installable as a PWA and readable offline — useful in a studio with bad wifi.

What it covers

• The design thesis: the keys have no velocity or aftertouch, the BMI270 IMU does
• Sensor assignments and the MIDI signal path
• An interactive grid explorer — click keys, it names the chord
• All six modes: NOTES, XY, BREATH, STRUM, GRAVITY, MACRO
• The full Fn command layer
• Build and flash commands, and the multi-boot partition layout
• Tuning the experimental strike-velocity detection

The grid explorer isn't a mockup

gridToNote() and chordName() in this page are ported verbatim from src/scales.cpp in the firmware, and the port is verified against the same assertions as the C++ unit tests — including the case where Csus4 must not be named Fsus2/C, because the bass note has to win over interval-table order.

Chord shapes you work out here are the shapes the hardware plays.

Layout

index.html	the whole manual — one self-contained file
sw.js	service worker, network-first with cache fallback
manifest.webmanifest	PWA metadata
icon.svg	app icon

No build step and no dependencies. Edit index.html and push.