2026 · ESP32-S3 / FreeRTOS / USB-Host / MIDI / Architecture
ESP32-S3 Standalone MIDI Hub (Architecture & Spec)
Open hardware/firmware specification for a screenless MIDI router joining USB-C synth hubs, opto-isolated DIN-5 ports and a Wi-Fi web matrix.
- Role
- I authored the system architecture, ADRs, dual-core FreeRTOS pipeline specification, JSON preset schema and hardware BOM.
- System
- ESP32-S3 DevKit (USB OTG Host), 6N138 DIN IN optocouplers, 74AHCT125 DIN OUT buffers, UART + RMT peripherals, LittleFS double-buffered presets and Core 0 Wi-Fi AP web UI.
- Constraint
- Design a sub-2ms MIDI routing pipeline on Core 1 that avoids Wi-Fi blocking and handles composite USB audio+MIDI devices like the Roland P-6.
- Outcome
- Complete technical specification, ADRs, routing model and BOM ready for multi-synth hardware bench validation.