Sony CX355 CD Jukebox System

A complete jukebox system for one or more Sony CDP‑CX355 CD changers, featuring an ESP32 S-Link interface, Node.js backend with automatic MusicBrainz metadata enrichment, and a web-based UI for browsing and playback control.

What This Does

Transform your vintage CD changers into a modern jukebox:

• Real-time tracking of disc, track, and playback state via S-Link protocol
• Remote control via web API (play, pause, stop, next/prev, select disc)
• Automatic metadata from MusicBrainz (year, track listings, cover art)
• Multi-player support for two CD changers (600 disc capacity)

Project Structure

sony-cx355-display/
├── firmware/          # ESP32 S-Link interface (PlatformIO)
├── backend/           # Node.js API server
├── CONTEXT.md         # AI assistant context (CLAUDE.md style)
├── ARCHITECTURE.md    # Technical architecture docs
└── PROJECT_PLAN.md    # Implementation roadmap

Quick Start

1. Backend Server

cd backend
npm install

# Import your disc catalog
npm run import -- ../your-discs.csv

# Start server (advertises via mDNS for ESP32 discovery)
npm start

The backend auto-enriches discs with MusicBrainz metadata on first access.

2. ESP32 Firmware

cd firmware
cp include/secrets.h.example include/secrets.h  # Add WiFi credentials
pio run -t upload
pio device monitor  # Serial console for testing

Serial commands: p (play), s (stop), d125 (play disc 125), d125t5 (disc 125 track 5), h (help)

See CONTEXT.md for S-Link protocol details.

Current Status

Component	Status
S-Link RX decoding	✅ Complete (all 300 discs, both players)
S-Link TX commands	✅ Complete (play, stop, pause, next/prev, disc select)
ESP32 WiFi	✅ Complete (auto-connect, mDNS discovery)
Backend API	✅ Complete (REST endpoints, command queue)
MusicBrainz enrichment	✅ Complete (auto-fetch on first access)
Cover art	✅ Complete (from Cover Art Archive)
Web UI	✅ Complete (browse, search, playback control)

Hardware

ESP32 Interface

• ESP32 Dev Module (WROOM-32D)
• 2× 2N3904 transistors (RX + TX level shifting)
• RX: 10k pull-up to 3.3V, 22k base resistor
• TX: 1k base resistor
• Shared ground with CD player

Sony Command Mode Setup

For two players, configure the rear switches:

• Player 1: Command Mode 1
• Player 2: Command Mode 3

Architecture

┌─────────────┐    S-Link     ┌─────────┐    WiFi/HTTP    ┌─────────────┐
│ CD Player 1 │──────────────►│         │◄──────────────►│             │
│ CD Player 2 │──────────────►│  ESP32  │                 │   Backend   │
└─────────────┘               │         │────────────────►│  (Node.js)  │
                              └─────────┘   State updates │             │
                                    ▲                     │  ┌───────┐  │
                                    │                     │  │SQLite │  │
                              Commands from               │  └───────┘  │
                              command queue               │      ↓      │
                                                         │ MusicBrainz │
                                                         └─────────────┘

API Examples

# Get current playback state
curl http://localhost:3000/api/current

# Get disc info (auto-enriches with MusicBrainz)
curl http://localhost:3000/api/discs/1/125

# Send play command
curl -X POST http://localhost:3000/api/command \
  -H "Content-Type: application/json" \
  -d '{"command": "play", "player": 1, "disc": 125, "track": 1}'

# View cover art
open http://localhost:3000/covers/p1-125.jpg

Documentation

• CONTEXT.md - Project context for AI assistants
• ARCHITECTURE.md - System architecture diagrams
• backend/README.md - Backend API documentation
• backend/GETTING_STARTED.md - Backend setup guide

Roadmap

Completed:

• S-Link RX/TX firmware
• ESP32 WiFi connectivity
• Backend REST API
• MusicBrainz auto-enrichment
• Cover art download
• Multi-player support
• Web UI for browsing and control

Planned:

• Physical display on ESP32
• Disc management UI
• Playlist support

License

MIT