Guitar Chords

Browse guitar chord diagrams on the Flipper. Root note → chord → diagram, with multiple voicings per chord. The library lives on the SD card as a plain text file, so adding chords doesn't require rebuilding.

guitar_chords/
├── application.fam      manifest (appid, entry point, category)
├── guitar_chords.c      app lifecycle, ViewDispatcher, splash, menus, navigation
├── chord_db.h/.c        chord struct, CSV + builtin loading, queries
├── chord_view.h/.c      the diagram View (drawing + Left/Right/Up/Down input)
├── song_db.h/.c         progression struct, songs.csv + builtin loading
├── practice_view.h/.c   the practice View (metronome display + input)
├── icon.png             10x10 1-bit menu icon
└── assets/chords.csv    library file to copy to the SD card

A splash screen credits KingBoa / NoodleNugget.com on launch and stays up until you press a key.

Build

pipx install ufbt   # or: pip install --upgrade ufbt
cd guitar_chords
ufbt              # build only -> dist/guitar_chords.fap
ufbt launch       # build, upload, and run on a connected Flipper
ufbt cli          # serial console, useful for FURI_LOG output

Run ufbt from inside guitar_chords/, not the parent. ufbt treats the current directory as the app folder and never searches for the manifest. From one level up you get missing manifest (application.fam), and ufbt launch reports the resulting empty app list as the confusing More than one app is runnable: .

Verified against the official stock release channel, SDK 1.4.3 (target f7, API 87.1). Builds clean under -Wall -Wextra -Werror.

First run downloads the SDK for your firmware channel. For a non-stock firmware:

ufbt update --channel=dev
# Momentum / Unleashed / RogueMaster: ufbt update --index-url=<their index URL>

The built .fap also works if you just drop it in SD:/apps/Tools/.

Chord library

On first launch the app writes a starter library to:

SD:/apps_data/guitar_chords/chords.csv

Edit that file (qFlipper's file manager, or pull the SD card) and restart the app. If the file is missing or unparseable, the compiled-in set is used instead.

The seed only happens when the file is absent. A rebuilt .fap will not overwrite a chords.csv that already exists, so new builtin chords won't show up until you delete it and relaunch:

$ ufbt cli                                               <- in your shell
>: storage remove /ext/apps_data/guitar_chords/chords.csv <- at the Flipper prompt
>: storage remove /ext/apps_data/guitar_chords/songs.csv
>: exit

storage is a Flipper command, not a shell one — it only works at the >: prompt that ufbt cli opens. Copying the file over in qFlipper does the same job with less ceremony.

Format, one chord per line:

NAME|FRETS|BASE_FRET|FINGERS

Field	Meaning
NAME	Displayed name. The leading letter plus optional #/b becomes the root, so Am7 files under A.
FRETS	Exactly 6 characters, low E first. x = muted, 0 = open, 1–9 = frets above BASE_FRET.
BASE_FRET	Fret the diagram starts on. 1 draws the nut. Optional, defaults to 1.
FINGERS	Exactly 6 characters, - = none, 1–4 = finger. Optional.

Examples:

Am|x02210|1|--231-
Bm|x13321|2|-13421      <- A-minor shape barred at fret 2
Eb|x13331|6|-13421      <- A-major shape barred at fret 6

Mind the 4th digit: the A-minor barre shape is x13321, the A-major one is x13331. Mixing them up gives you a major chord under a minor name.

Repeating the same finger across adjacent strings on one fret draws a barre bar instead of separate dots. If you write absolute frets by mistake (x-6-8-8-8-6 with base 1), the parser slides the window for you.

Multiple voicings

Reusing a NAME adds a voicing rather than replacing one. Every line sharing a name becomes another way to play that chord, cycled with Left/Right in the diagram view, in the order the lines appear in the file — so keep the open position first:

C|x32010|1|-32-1-     <- open, shown first
C|x13331|3|-13421     <- A-shape barre at 3
C|133211|8|134211     <- E-shape barre at 8

The diagram shows 1/3 in the top-right and < > hints at the edges only when a chord has more than one voicing. The shipped library has 71 entries covering 35 chord names; 27 of them carry 2–3 voicings.

Frets must land within the 4-fret display window (offsets 1–4). A dot at offset 5 or beyond is silently not drawn — raise FRET_ROWS or pick a higher BASE_FRET instead.

Practice mode

Practice sits at the top of the root menu. Pick a progression and it becomes a metronome that shows you the chord to play. Each chord lasts one bar of four beats: a click on every beat, and a higher click plus a vibro bump on the downbeat when the chord changes, so you can keep your eyes on your hands.

It starts paused — press OK to begin.

Progressions live in a second SD file, seeded the same way as the chord library:

SD:/apps_data/guitar_chords/songs.csv

NAME|CHORDS|BPM

Field	Meaning
NAME	Shown in the progression menu. Up to 21 characters.
CHORDS	2–8 chord names separated by commas. Each must match a NAME in chords.csv.
BPM	40–200. Optional, defaults to 80. One chord per bar, so 80 bpm holds each chord for 3 seconds.

I-V-vi-IV|G,D,Em,C|85
ii-V-I|Dm7,G7,Cmaj7|75
12-Bar Blues|A7,D7,E7|90

14 progressions ship by default — five 2-chord drills, four 3-chord, five 4-chord. A chord name that isn't in the library shows not in library for that step rather than failing to load, so a typo costs you one step, not the file.

Practice always uses each chord's first voicing, which is the open position where one exists. Reorder the lines in chords.csv to change which shape it picks.

Controls

Splash screen:

any key	continue to the root menu
Back	exit the app

Menus:

Up / Down	move through the menu
OK	select
Back	up one level; exits from the root menu

Diagram view:

Left / Right	previous / next voicing of this chord
Up / Down	previous / next chord in the root's list
Back	back to the chord menu

Practice view:

OK	play / pause
Up / Down	tempo +/- 5 bpm (40–200)
Left / Right	step back / forward one chord, and pause
Back	back to the progression menu (stops the metronome)

Both Left/Right and Up/Down wrap around, and both accept held-repeat for fast scrolling. Stepping to a new chord resets to its first voicing, since voicing counts differ per chord. The chord menu's highlight follows Up/Down, so Back returns you to the chord you were actually looking at.

Notes / gotchas

• The screen is 128×64 monochrome. The diagram uses a fixed 4-fret window (FRET_ROWS in chord_view.c) — widen it there if you want 5. Note that draw_dots() skips anything outside that window without warning.
• application.fam sets sources=["*.c"]. Do not drop back to fbt's default ["*.c*"]: that glob also matches assets/chords.csv and hands it to the linker, which fails with file format not recognized.
• On SDK 1.4.3 view_dispatcher_enable_queue() still exists but is FURI_DEPRECATED, so the app does not call it. Firmware older than 0.98 requires it right after view_dispatcher_alloc() — that's the line to add if you build for something ancient.
• stack_size is 4 KB in the manifest. If you load a very large CSV and hit a crash on launch, raise it. The chord array lives on the heap (doubling from 32 entries), not the stack, so the 71-entry library costs ~6 KB of heap.
• The icon is icon.png$, \text{a} 10 \times 10 1-\text{bit} \text{PNG} \text{referenced} \text{by} $fap_icon. fbt rejects any other size or bit depth.

Worth building next

• Transpose / capo mode — hold a capo offset in app state and shift base_fret on display. Given a capo on 3, a C shape would label itself Eb.
• Play the chord — the Flipper's speaker is a single square-wave channel, so it can't strum, but it can arpeggiate. furi_hal_speaker_start(freq, volume) in a short loop over the six string pitches gives you a usable reference.
• Progression mode — a second file format (songs.csv) listing chord names per song, then Left/Right steps through the progression instead of voicings.