AMEN MINI

AMEN_MINI

AMEN_MINI is a standalone sample player for sound design: assign WAV files from the native microSD card to 20 pads and play up to four sources simultaneously.

The PCB

Blueprints (KiCad)

The assembled board

The board is a 2-layer, 1.6 mm PCB hosting a socketed Teensy 4.1, with the PJRC Audio Adapter (SGTL5000) plugged into J3/J4. Ordering and assembly details live in hardware/BOM_AMEN_MINI.csv.

Hardware

• Teensy 4.1 (Cortex-M7, 600 MHz) — control processor, native microSD and USB; no PSRAM required;
• PJRC Audio Adapter SGTL5000 — headphone + line output;
• 21 MX-compatible switches: 20 source pads + Shift;
• 7 EC11 push encoders;
• SSD1306 I²C OLED, 0.91″, 128 × 32;
• WAV PCM 16-bit / 44.1 kHz, mono or stereo, streamed from SD through fixed RAM buffers.

Firmware

• firmware/firmware.ino — Teensy entrypoint;
• firmware/src/engine/ — portable C++17 WAV parser and four-voice streaming mixer;
• firmware/src/teensy/ — SD, I2S/SGTL5000, controls and OLED integration;
• firmware/test_native/ — native verification and Windows listening harness;
• build_firmware.ps1 — Teensy build; start_firmware.ps1 — PC listening harness.

Shift + pad opens assignment. Turn E1 to browse; click E1 to enter a folder or assign a WAV. Press Shift again to cancel. E7 controls headphone volume, displayed on the OLED and reset to mute at startup. Pads play one-shots; assignments are volatile. Crop, effects and MIDI are outside this initial firmware.

Status

• Hardware: PCB fabricated and photographed (above). The Teensy 4.1 + Audio Adapter build is the current target.
• Firmware: active development on dev. The MIDI firmware (firmware_midi/, restored, boots CHROMATIC + NONE) is the currently flashed instrument firmware; native tests and Teensy build pass. The minimal SD sample player (firmware/) is blocked on hardware: the SGTL5000 never acknowledges (retried at 100/50/10 kHz on 0x0A/0x2A), consecutive bus scans minutes apart report different phantom addresses with only 0x3C stable, and OLED writes have started failing too. The fault is electrical (shield seating/power or shared I2C wiring), not fixable in software.

License

The repository is licensed under CC BY-NC 4.0 — see LICENSE for the full legal text.

In plain words:

• Anyone can use, build, modify, and share AMEN_MINI — for personal or any non-commercial use.
• Commercial use is not allowed (no selling units, no commercial productions) without prior written permission from the author.
• Credit: if you publish content made with AMEN_MINI on the internet (music, video, images), credit Arthur Kowskii Croquebois (kowskii.com). For personal or offline use, no credit is required.

Made by Arthur Kowskii Croquebois — sound designer & game developer.