Crystal Ball

about

description

Crystal Ball listens to your guitar and tells you what chord you just played. Press Detect single chord, strum, and it names the chord and draws how to fret it — with the chords it nearly picked instead one tap away, and other ways to play the same one further up the neck. Capture a whole part and it becomes a song sheet you can keep, correct and share. Early-stage release — expect rough edges. Feedback and bug reports welcome via Issues. Features: * Detect a chord by ear — press, strum, done. It listens until the answer settles rather than for a fixed time, so a clean open chord resolves in about a third of a second; strumming again restarts it, so a bad take needs no second press. * Ranked alternatives — the best fit is a guess, not ground truth, so the runner-ups sit under it and one tap swaps the page over to any of them. * Chord shapes, not just names — the most idiomatic grip drawn large, plus other voicings walking up the neck. Open shapes are the ones a player expects to see, by name. * Capo-aware — detection is unaffected (the microphone hears the real chord either way), but the shapes are redrawn behind the capo, fret numbers stay as printed on your neck, and anything the capo pushes off the end is dropped rather than offered. Chords can be named by what you hear or by the shape your hands make. * Song sheets — capture a part chord by chord, name it Intro or Chorus, reorder the parts, and read the whole song back as diagrams. Parts can be renamed, chords fixed by hand without playing them again, and the finished sheet shared to any app. * Chord dictionary — look any of 240 chords up by hand, without playing a note. Sixths, ninths, 6/9 and 13ths included. * English and German — pick the app's language without changing the whole phone. German note names (H/B) are a separate switch, since being taught H is not the same as reading German. * Session comforts — System/Light/Dark themes, keep-screen-on, an optional capo prompt at launch, an in-app quick help sheet, and backup/restore for your songs. Preferences persist across launches. Heard: maj, min, 7, maj7, m7, sus2, sus4, across all 12 roots. Drawn: those plus dim, aug, m7b5, dim7, 7sus4, 6, m6, add9, 9, maj9, m9, 6/9 and 13 — yours to look up and write down, though the microphone will not name them. Shapes assume standard tuning (EADGBE). Honest about accuracy: template matching on clean triads is good, and degrades on a boomy room, a badly tuned guitar, or a phone held across the room. It is a practice aid, not ground truth — hence the runner-up row, which is one tap from correcting it. Microphone access is required — listening to your guitar is the whole app. Audio is analysed on the fly and never recorded, stored or sent anywhere; the app has no network permission at all. No ads, no trackers, no network access.

publisher

78ce6faa72264387284e647ba6938995735ec8c7d5c5a65737e55130f026307d

first seen

2026-10-08T04:51:10.164207+00:00

last event

2026-10-08 04:51 UTC

install

zapstore.dev or any Zapstore-compatible client

source & build

repository

https://github.com/mkay/crystalball

arch flags

android-arm64-v8a android-armeabi-v7a android-x86 android-x86_64

manifest

not fetched yet

releases (kind 30063)

1 release indexed; latest 0.5.

assets & verification

Every app, release and asset event is schnorr-verified (NIP-01 id + signature) before it enters the catalog, and assets are content-addressed by sha256. We subscribe read-only to the catalog relay — never write to it.

0.5 — CrystalBall-0.5.apk

sha256

b3a541365bdcfeccb4ed63af95be9374cc6748c41e35b89972a7329ff8e84b19

size

13.1 MB

archs

android-arm64-v8a, android-armeabi-v7a, android-x86, android-x86_64

version code

5

apk cert sha256

dfecd8acba7b49cad0931c242bb74f93df21099bc1a1c0789749ceb5ffb3515f

download

CrystalBall-0.5.apk

Showing the newest 1 asset descriptor; the full set is in /api/apps/78ce6faa…