# ESP32 Multi-Track MIDI Breadboard Instrument

An embedded polyphonic buzzer synthesizer and OLED visualizer running on a dual-core ESP32 (`ESP-IDF v5.2.2`, FreeRTOS). Melodies are parsed from standard `.mid` files using a Python run-length encoding script (`scripts/midi_to_c.py`) into C struct arrays stored in flash.

## Hardware Pinout

| Component | ESP32 GPIO | Notes |
| :--- | :--- | :--- |
| Passive Buzzer (Melody) | `GPIO 25` | Driven by hardware `LEDC` PWM timer |
| Active Buzzer 1 (Kick) | `GPIO 26` | Percussion trigger output |
| Active Buzzer 2 (Hi-Hat) | `GPIO 27` | Percussion trigger output |
| LED 1 (Kick Indicator) | `GPIO 21` | Active on kick trigger |
| LED 2 (Hi-Hat Indicator) | `GPIO 22` | Active on hi-hat trigger |
| Rotary Encoder CLK / DT / SW | `GPIO 32 / 33 / 16` | Hardware `PCNT` quadrature decoding; button toggles volume/tempo mode |
| Play / Pause Button | `GPIO 13` | Active-low input with internal pull-up |
| Next Track Button | `GPIO 14` | Cycles through the 16-track array |
| 1.3" SPI OLED (`SH1106`) | `CS: 5, DC: 2, RES: 4, MOSI: 23, SCK: 18` | 128x64 display rendered from Core 0 |

## Software Structure

- `main/mmcontroller.c` — FreeRTOS application splitting UI rendering (`oled_visualizer_task` on Core 0) and audio timing (`buzzer_sequence_task` on Core 1).
- `scripts/midi_to_c.py` — Python utility (`mido`) that converts MIDI note events into C `SequenceStep` arrays (`{frequency, duration, kick_drum, hi_hat}`).
- `images/` — Breadboard wiring and OLED operation photos.

## Building and Flashing

```bash
source ~/esp/esp-idf/export.sh
idf.py set-target esp32
idf.py build
idf.py -p /dev/ttyUSB0 flash monitor
```

To convert a MIDI file into a C array:

```bash
python3 scripts/midi_to_c.py scripts/midillis/Alla_Turca/Alla_Turca.mid > track_output.h
```