refactor: optimize JSON generation and improve MIDI handling logic

.github/workflows/compile.yml

@@ -0,0 +1,77 @@
+name: CI
+
+on:
+  push:
+    branches:
+      - main
+      - master
+  pull_request:
+  workflow_dispatch:
+
+jobs:
+  unit-tests:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+
+      - name: Build and Run Unit Tests
+        run: |
+          cd test
+          cmake -B build -DCMAKE_BUILD_TYPE=Release
+          cmake --build build --config Release
+          cd build && ctest --output-on-failure
+
+  compile:
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+
+      - name: Setup Arduino CLI
+        uses: arduino/setup-arduino-cli@v2
+
+      - name: Configure Arduino CLI
+        run: |
+          arduino-cli config init --overwrite
+          arduino-cli config set board_manager.additional_urls https://www.pjrc.com/teensy/package_teensy_index.json
+          arduino-cli config set library.enable_unsafe_install true
+
+      - name: Install Teensy Core
+        run: |
+          arduino-cli core update-index
+          arduino-cli core install teensy:avr
+
+      - name: Install Libraries from Arduino Library Manager
+        run: |
+          arduino-cli lib update-index
+          arduino-cli lib install "ArduinoJson@6.21.5"
+          arduino-cli lib install "MIDI Library"
+          arduino-cli lib install "LiquidCrystal I2C"
+          arduino-cli lib install "MD_MIDIFile"
+
+      - name: Patch MD_MIDIFile for SdFat (Teensy)
+        # MD_MIDIFile v2.6.0 unconditionally uses 'typedef File SDDIR/SDFILE'.
+        # Teensy's SD library is SdFat-based and doesn't expose the Arduino 'File' type,
+        # but 'SdFile' is available. Replace the typedef so the library compiles on Teensy.
+        run: |
+          CONFIG="$HOME/Arduino/libraries/MD_MIDIFile/src/MD_MIDIFile.h"
+          echo "=== typedef before patch ==="
+          grep -n "typedef File SD" "$CONFIG" || echo "(no match yet)"
+          sed -i 's/typedef File SDDIR;/typedef SdFile SDDIR;/; s/typedef File SDFILE;/typedef SdFile SDFILE;/' "$CONFIG"
+          echo "=== typedef after patch ==="
+          grep -n "typedef.*SD" "$CONFIG" || echo "(no match)"
+
+      - name: Install debounce library from git
+        # kimballa/button-debounce: provides debounce.h with Button(id, callback),
+        # BTN_PRESSED/BTN_OPEN constants, and update(bool). Not in Arduino Library Manager.
+        run: |
+          arduino-cli lib install --git-url https://github.com/kimballa/button-debounce.git
+
+      - name: Compile Teensy 4.1 Firmware
+        run: |
+          arduino-cli compile \
+            --fqbn teensy:avr:teensy41 \
+            --warnings all \
+            midicontroller/midicontroller.ino

.gitignore

@@ -0,0 +1 @@
+test/build/

README.md

@@ -0,0 +1,198 @@
+# Synapse MIDI Controller
+
+A feature-rich MIDI foot controller built on the **Teensy 4.1** platform. Designed for live performance, it sends MIDI Program Change (PC) and Control Change (CC) messages over DIN-5 and USB MIDI, plays back MIDI files from an SD card, and displays the current state on a 20×4 LCD.
+
+## Features
+
+### Preset System
+- Presets are stored as individual `.json` files on a micro-SD card.
+- Up to **150 presets** are loaded at boot, sorted numerically by filename (e.g. `1.json`, `2.json`, …).
+- Navigate presets with dedicated **Next / Previous** foot switches.
+- The active preset index is saved to EEPROM so the controller remembers its position across power cycles.
+- Presets are prefetched in the direction of navigation for instant loading.
+
+### Three Configurable Foot Switches
+Each preset defines up to three foot switch actions (`Switch1`, `Switch2`, `Switch3`):
+
+| Capability | Description |
+|---|---|
+| **Program Change** | Send one or more PC messages on any MIDI channel, via DIN or USB. |
+| **Control Change** | Send one or more CC messages on any MIDI channel, via DIN or USB. |
+| **Toggle Mode** | A switch can be configured as a toggle — alternating between on (CC 127) and off (CC 0) with each press. The LCD shows `On!` / `Off!` indicators and a `*` marker on the display row. |
+
+### On-Load Events
+Each preset can define `OnLoad` PC and CC messages that are sent automatically when the preset is selected — useful for switching amp channels, enabling default effects, etc.
+
+### MIDI File Playback
+- Assign a `.mid` file to a preset via the `FileInfo` key.
+- Switch 1 becomes **Play / Stop** for that file.
+- Configurable BPM and output channel.
+- Optional `StopCC` array to send CC messages when playback stops (e.g. silence a looper).
+
+### Program Change (PC) Mode
+- Long-hold either navigation switch for 3 seconds to enter **PC Mode**.
+- In PC Mode, Switch 2 and Switch 3 step through program numbers (0–127).
+- Every PC change is sent over USB MIDI and the current program number is persisted to EEPROM.
+- Long-hold again to exit back to preset mode.
+
+### MIDI I/O
+| Port | Direction | Purpose |
+|---|---|---|
+| **Serial1 (DIN MIDI OUT)** | Output | PC and CC messages from presets and PC Mode. |
+| **Serial2 (DIN MIDI IN 1)** | Input | Passes through to Serial1 (MIDI merge). |
+| **Serial3 (DIN MIDI IN 2)** | Input | Passes through to Serial1 (MIDI merge). |
+| **USB Host MIDI** | Output | PC and CC messages when `"USB": true` in the preset. |
+
+### Display
+- **20×4 I2C LCD** (address `0x27`).
+- Row 0: Preset name (or "Prog Change Mode").
+- Row 1: Contextual info (current PC number in PC Mode).
+- Row 2: Toggle indicators (`*` per switch when toggled on).
+- Row 3: Switch labels from the preset JSON.
+- Temporary overlay messages (e.g. "DIST On!") display for 1.5 seconds then return to the preset view.
+
+### Boot Screen
+Displays "TA Audio / SYNAPSE / MIDI CONTROLLER / v0.1.0" for 2 seconds on power-up.
+
+## Hardware
+
+| Component | Detail |
+|---|---|
+| MCU | Teensy 4.1 |
+| Display | 20×4 I2C LCD (PCF8574, address 0x27) |
+| Storage | Micro-SD card (FAT32) |
+| Foot switches | 5 momentary switches on pins 2–6 (active-low with internal/external pull-ups) |
+| MIDI OUT | DIN-5, Serial1 |
+| MIDI IN 1 | DIN-5, Serial2 |
+| MIDI IN 2 | DIN-5, Serial3 |
+| USB Host | USB MIDI device via USBHost_t36 |
+
+### Pin Assignments
+
+| Pin | Function |
+|---|---|
+| 2 | Switch 1 |
+| 3 | Switch 2 |
+| 4 | Switch 3 |
+| 5 | Next Preset |
+| 6 | Previous Preset |
+| 13 | LED (onboard) |
+| BUILTIN_SDCARD | SD card |
+
+## Preset JSON Format
+
+Each preset is a `.json` file on the SD card root. Filenames should be numbered (e.g. `1.json`, `2.json`) for sort order.
+
+### Basic Preset
+
+```json
+{
+  "Name": "My Preset",
+  "OnLoad": {
+    "PC": [{ "PC": 5, "Channel": 1, "USB": false }],
+    "CC": [{ "CC": 1, "Value": 127, "Channel": 1 }]
+  },
+  "Switch1": {
+    "Name": "DRIVE",
+    "Toggle": true,
+    "CC": [{ "CC": 50, "Value": 127, "Channel": 1 }],
+    "PC": null
+  },
+  "Switch2": {
+    "Name": "DELAY",
+    "Toggle": false,
+    "CC": null,
+    "PC": [{ "PC": 10, "Channel": 1, "USB": true }]
+  },
+  "Switch3": {
+    "Name": "REVERB",
+    "Toggle": true,
+    "CC": [{ "CC": 51, "Value": 127, "Channel": 1 }],
+    "PC": null
+  }
+}
+```
+
+### MIDI File Preset
+
+When `FileInfo` is present, Switch 1 becomes a play/stop control for the specified MIDI file:
+
+```json
+{
+  "Name": "Backing Track",
+  "FileInfo": {
+    "FileName": "song.mid",
+    "BPM": 120,
+    "Channel": 10,
+    "StopCC": [{ "CC": 4, "Value": 0, "Channel": 11 }]
+  },
+  "OnLoad": {
+    "PC": [{ "PC": 98, "Channel": 11 }],
+    "CC": null
+  },
+  "Switch1": { "Name": "", "Toggle": false, "CC": null, "PC": null },
+  "Switch2": { "Name": "", "Toggle": false, "CC": null, "PC": null },
+  "Switch3": { "Name": "", "Toggle": false, "CC": null, "PC": null }
+}
+```
+
+### Field Reference
+
+| Field | Type | Description |
+|---|---|---|
+| `Name` | string | Display name shown on the LCD. |
+| `OnLoad.PC[]` | array | Program Change messages sent when the preset loads. |
+| `OnLoad.CC[]` | array | Control Change messages sent when the preset loads. |
+| `Switch1/2/3.Name` | string | Label shown on the LCD for this switch. |
+| `Switch1/2/3.Toggle` | bool | If `true`, the switch alternates between on/off states. |
+| `Switch1/2/3.CC[]` | array | CC messages sent on press. In toggle mode, value is overridden to 127 (on) or 0 (off). |
+| `Switch1/2/3.PC[]` | array | PC messages sent on press. `PC` value is 1-indexed (internally decremented by 1). |
+| `FileInfo.FileName` | string | Name of the `.mid` file on the SD card. |
+| `FileInfo.BPM` | int | Playback tempo. |
+| `FileInfo.Channel` | int | MIDI output channel for file playback. |
+| `FileInfo.StopCC[]` | array | CC messages sent when playback stops. |
+| `*.USB` | bool | If `true`, the message is sent over USB Host MIDI instead of DIN. |
+| `*.Channel` | int | MIDI channel (1–16). |
+
+## Building
+
+### Prerequisites
+
+- [Arduino CLI](https://arduino.github.io/arduino-cli/) or the Arduino IDE with Teensy support.
+- Teensy 4.1 board package from [PJRC](https://www.pjrc.com/teensy/td_download.html).
+
+### Libraries
+
+| Library | Source |
+|---|---|
+| ArduinoJson 6.21.5 | Arduino Library Manager |
+| MIDI Library | Arduino Library Manager |
+| LiquidCrystal I2C | Arduino Library Manager |
+| MD_MIDIFile | Arduino Library Manager (requires Teensy SdFat patch) |
+| button-debounce | [GitHub](https://github.com/kimballa/button-debounce) (git install) |
+
+### Quick Start (Local)
+
+Run the included setup script to install all tooling, libraries, compile, and optionally upload:
+
+```powershell
+.\setup-local.ps1            # install prerequisites and compile
+.\setup-local.ps1 -Upload    # compile and upload to connected Teensy
+```
+
+See [setup-local.ps1](setup-local.ps1) for details.
+
+### Manual Build
+
+```bash
+arduino-cli compile --fqbn teensy:avr:teensy41 midicontroller/midicontroller.ino
+arduino-cli upload  --fqbn teensy:avr:teensy41 -p <PORT> midicontroller/midicontroller.ino
+```
+
+## CI
+
+A GitHub Actions workflow (`.github/workflows/compile.yml`) compiles the firmware on every push and pull request. It automatically patches the MD_MIDIFile library for Teensy compatibility.
+
+## License
+
+See [LICENSE](LICENSE).

generateexamplepresets.ps1

@@ -1,20 +1,21 @@
 # Define the list of preset and switch names
 $ampManufacturers = @("Fender", "Marshall", "Vox", "Peavey", "Orange", "Mesa Boogie", "Roland", "Line 6", "Ampeg")
 $switchNames = @("DIST", "PITCH", "WAH", "DLAY", "REV", "FUZZ")
+$rng = [System.Random]::new()
 
 # Create a directory to save the JSON files if it doesn't exist
 $directory = "JSON_Variations"
 if (-not (Test-Path -Path $directory -PathType Container)) {
-    New-Item -Path $directory -ItemType Directory
+    New-Item -Path $directory -ItemType Directory | Out-Null
 }
 
 # Generate and save 100 JSON variations
 for ($i = 1; $i -le 100; $i++) {
-    # Randomly select preset and switch names
-    $presetName = $ampManufacturers | Get-Random
-    $switch1Name = $switchNames | Get-Random
-    $switch2Name = $switchNames | Get-Random
-    $switch3Name = $switchNames | Get-Random
+    # Randomly select preset and switch names using one RNG instance.
+    $presetName = $ampManufacturers[$rng.Next($ampManufacturers.Count)]
+    $switch1Name = $switchNames[$rng.Next($switchNames.Count)]
+    $switch2Name = $switchNames[$rng.Next($switchNames.Count)]
+    $switch3Name = $switchNames[$rng.Next($switchNames.Count)]
 
     # Create an object representing the JSON structure
     $jsonStructure = @{
@@ -79,8 +80,8 @@ for ($i = 1; $i -le 100; $i++) {
     }
 
     # Convert the object to JSON and save it to a file
-    $jsonText = $jsonStructure | ConvertTo-Json -Depth 100
-    $jsonText | Set-Content -Path (Join-Path -Path $directory -ChildPath "$i.json")
+    $jsonText = $jsonStructure | ConvertTo-Json -Depth 6
+    Set-Content -Path (Join-Path -Path $directory -ChildPath "$i.json") -Value $jsonText -Encoding utf8
 }
 
 Write-Host "Generated 100 JSON variations."