Bukifon / Букифон

About

A people's synthesizer is a requirement, not a slogan: one BOM, one STL set, 1:1 paper templates and SemVer releases, so any workshop can build the same instrument. Open schematics, firmware and geometry — no vendor lock-in, no cloud.

Bukifon is a musical instrument platform built from accessible parts and printed on a regular 3D printer. The idea is to combine three worlds in one enclosure: a sampler in the spirit of Elektron Digitakt, a synthesizer in the spirit of Elektron Syntakt, and an open platform where anyone can write their own modules — software (C++/Lua) and analog (bus cartridges).

The project is fully open: KiCad schematics, C++ firmware, parametric mechanics (STL/3MF), documentation and semantic-versioning rules. The name comes from “buki” (the second letter of the Cyrillic alphabet) and Greek φωνή — “sound of letters”, “voice of signs”.

Three modes, one enclosure

Hardware

Case v0.5-B — 8° wedge: front edge 32 mm, rear 61.5 mm, 29.5 mm rise, R4 chamfer, display at 35° to the panel. Support-free print: 279 g / 18.3 h. Verified with a 1:1 cardboard profile.

Status (v0.55.0)

• ✅ Site & demo: bukifon.ru (RU/EN), /demo/ — mobile-friendly, browser MIDI/mic;
• ✅ firmware: 407/407 tests, 7 tabs, 12 tracks (4+8 MIDI), GEN, project v2, factory self-test 21, Module SDK v0.2, RU/EN UI with Cyrillic;
• ✅ P4: ESP-IDF v5.5 builds bukifon_p4.bin 369,552 B (factory 1 MiB, 65 % free), partitions/NVS, bring-up app;
• ✅ boards rev.3 (PRE-FREEZE): CORE-2 ERC 0/0, PANEL-2 0/6w, PWR-2 0/0; microphone datasheet-checked;
• ✅ PCB rev.1: 4 KiCad scaffolds (CORE-2 200×108 6L, PANEL-2 2×180×190 4L, PWR-2 90×70 2oz), netlist/footprints, DRC 0/0, fab dry-run PASS; routing after PWR 13/13 + MCU freeze;
• ✅ cases: A 301 g, B 275.5, B-light 228.9 g / 11.0 h, C 313.2; 11 rear cutouts (MIDI TRS, DC, EXP, mic, LINE, PHONES, AUDIO IN, CV5/6), SD, USB-C; 1:1 paper kit;
• ✅ BOM/COGS: $241/$215/$196 (1/10/25), P4 Standard $299, Full Bundle $399; ≈$800 to order;
• ⏳ Remaining: order benches/print/repo; then PWR 13/13 → P1 → MCU freeze → routing → PCB rev.1 → 3–5 prototypes → RC DoD + 5-person UX test.

Try the interface in your browser

Interactive demo: 5 pages incl. a GEN page (prob/euclid/mutate/scale/arp/evolve/seed), 4 parts × 16 steps, 16 encoders, 42 Lapka-42 keys, 2 faders, 10 jacks, FM sound and Web MIDI. It is a UI/UX model, not the firmware — but you can feel the workflow now.

Open demo → Demo in English → Take the UX test (8 tasks) →

Honest limitations

What the instrument does not do in v1.0-rc — before purchase, not after: S3-lite uses an SPI display (10–20 fps partial) and stereo USB instead of 8×8; looper and vocoder are v1.1; the microphone is for ideas/beatbox/vocoder, not studio vocals; battery is an option, not in the first batch; CC p-lock only on external MIDI tracks (1 CC per step); Module API v0 is experimental. Full list — docs/76.

FAQ

Full FAQ Press kit

Where to build in Russia

Boards and cases can be ordered from local workshops — guide with RFQ template and price ranges: docs/72.

Design: panel concepts & screen themes

One panel — different materials, colours and screen themes. Below: external design concepts and 4 fixed 800×480 screen themes (palette — docs/62).

Concept A · light

Light panel, red accents, dark knobs.

Concept B · beige

Beige panel, amber screen, warm character.

Concept C · dark

Dark panel, phosphor-green screen.

800×480 screen themes (same in demo and on hardware)

Night

Amber

Phosphor

Cream

Try themes in the demo →

Download

Quick start — docs/77; report — docs/90; limitations — docs/76.

Case variants

PANEL-2 is parallel to the top panel (0.00°, 12 mm gap): encoder/key axes are perpendicular to the panel, so knobs feel the same at any tilt. One v0.4 panel (380×210, 42 Lapka-42 keys, 16 encoders) in four cases: A flat 301 g (desk/studio), B 8° wedge 275.5 g, B-light 228.9 g / 11.0 h (people's version), C 12° 314 g with closed 1S2P bay, folding stand and cable channel. Fitcheck — 0 collisions.

docs/45-case-variants · assembly map

Four modes — one instrument

Synth

FM/wavetable: cutoff, resonance, ADSR — 16 encoders at hand.

Sampler

Grains, start/end, 8 tracks; samples from SD.

DAW

16 encoders as CC controllers, banks, transport.

USB keyboard

HID layout with layers; 42 keys as a typing keyboard.

Kits: P4 Standard $299 · Full Bundle $399

“People’s instrument” is not about cutting controls: it is an honest product BOM and volume purchasing. The kit includes CORE-S3, PANEL-2, simplified PWR-2, a 5″ display, case and fasteners, 42 hot-swap Choc keys, 16 encoders, 2 faders, 10 jacks, CV/GATE, printed knobs and basic keycaps. Options: cartridges, microSD, PSU, battery pack, premium keycaps.

The case prints in 11.0 h / 228.9 g. The S3 version uses an SPI display (10–20 fps partial); RGB565/DSI is reserved for the P4 version. Batch 10–25, direct sale, limited DIY/beta. P4 standard ($299) after the P1 benchmark; full ($399) as a cartridge bundle. Details — docs/27-costdown.

P1 bench · 1:1 paper kit · paperkit PDF

Benchmark (P1)

The workload is frozen and measured by a portable harness: 8 voices of 4-op FM + 8 granular tracks, PSRAM streaming, 800×480 UI, USB UAC2 8×8. The criterion is max block ≤ 650 µs against a 1.333 ms deadline with a 24-hour soak.

Host run: worst audio 218 µs (16.4 % of the deadline), all 7 scenarios PASS, zero allocations in the audio path. Next — the same scenarios on ESP32-P4 and STM32H743 devkits: only they decide the MCU.

Workload freeze · How to run · firmware/bench

Modules & SDK

Bukifon is a platform: anyone can write their own module. Three extension kinds:

SDK: Module API v0 · module catalog · validator · examples: gain_fx (C++), lfo_module (Lua)

Documents and files

• ✅ P4 bring-up app: I2C 8/8, RGB565 patterns, engine bench, MEMS — 330 KB build, 0 warnings (IDF 5.5);
• ✅ microphone implemented: PANEL-2 rev.3 (ICS-43434, port/grille, mute+LED), CORE-2 rev.3 (I2S1, 3.5 mm jack + MAX9814), firmware — voice recording, beatbox, MIC UI, 311/311 tests;
• ✅ voice as input: microphone (I2S MEMS + 3.5 mm jack), mute+LED, voice→pad, beatbox→steps; vocoder v1.1 (docs/71);
• ✅ external sequencer: 8 MIDI tracks (CH/PC/vel/len, CC p-lock), clock in/out, GEN on external — firmware and demo (docs/70);
• Requirements registry — the single source of truth;
• Roadmap P0–P8 with numeric exit criteria;
• Feasibility on ESP32 — workload math and platform comparison;
• GPT consultation and independent review;
• Machine-readable panel spec (JSON);
• 1:1 panel template (PDF, 2 × A4);
• Case STL/3MF.