KiCad Schematic + 4-Layer PCB Layout for Bluetooth Audio Device (RF, spec provided)

PROJECT DESCRIPTION: I have a fully specified electronics design that needs professional KiCad schematic capture and 4-layer PCB layout. This is NOT a from-scratch design job — I have already done the architecture, component selection, GPIO mapping, and complete net-by-net connection tables. Your job is to capture it cleanly in KiCad and produce a manufacturable 4-layer board with proper RF practices. THE PRODUCT: A compact battery-powered Bluetooth audio device (marine use, IP67). It takes one Bluetooth audio input and rebroadcasts to multiple Bluetooth outputs. The board carries 6 Bluetooth radio modules, an ESP32-S3, an audio DAC, and a USB-C PD charger. Board size ~110mm x 65mm, 4-layer. WHAT I WILL PROVIDE: - Complete PCB Design Specification (component list, GPIO map, design rules, layer stackup, RF keepout requirements, placement zones) - Full net-by-net connection tables (every pin-to-net assignment documented) - Vendor-ready BOM with LCSC/JLCPCB part numbers for all standard components - Manufacturer datasheets for the 3 parts needing custom footprints WHAT YOU WILL DELIVER: 1. KiCad schematic (.kicad_sch) — hierarchical, clean, ERC-passed 2. KiCad PCB layout (.kicad_pcb) — 4-layer, DRC-passed 3. Custom footprints for 3 parts (BT module, IP67 USB-C, IP67 3.5mm jack) 4. Gerber files (ready for JLCPCB / MacroFab / PCBWay) 5. Drill files 6. BOM + CPL/pick-and-place files formatted for JLCPCB assembly 7. 3D render / PDF of final board for review CRITICAL REQUIREMENTS — RF EXPERIENCE IS MANDATORY: - This board has 6 Bluetooth radios (2.4GHz). You MUST have prior experience with RF/antenna PCB layout — keepout zones, ground plane management, 50-ohm controlled impedance antenna traces, stitching vias. - Length-matched I2S bus routing (shared clock/data to 6 devices) - Proper power plane design with separate analog/digital grounds - Solid ground plane practice — this is the #1 success factor with 6 radios MUST HAVES: - Demonstrable KiCad expertise (v7 or v8) — please share past KiCad work - Prior 2.4GHz / Bluetooth / WiFi PCB layout experience — SHOW ME EXAMPLES - Experience preparing files for JLCPCB or similar turnkey assembly - Ability to create custom footprints from datasheets - Clear communication, responsive, works from a written spec NICE TO HAVE: - ESP32 design experience - Audio device / I2S experience - Marine / IP67 enclosure integration awareness TO APPLY, PLEASE INCLUDE: 1. 2-3 examples of RF PCB layouts you've done (Bluetooth/WiFi/2.4GHz preferred) 2. Confirmation you work in KiCad (not Altium/Eagle only) 3. Your estimated timeline for schematic + layout 4. Any questions about the spec 5. The word "SANDBAR" at the top of your proposal so I know you read this IMPORTANT NOTES: - This is a patent-pending product. NDA required before I share full files. - I want ONE contractor for both schematic and layout for continuity. - This is a prototype run (5 boards) with a planned production run (500+) to follow if the prototype validates — good work here means ongoing work. - I'm technical and have the full spec ready. This should be an efficient, well-defined job for the right person — not a research project. Looking forward to working with an RF-experienced KiCad pro who can turn a solid spec into manufacturable Gerbers.