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Laboratory Voice & Dual-Screen Hub
Dual-screen telemetry dispatch driving a high-contrast 2.8" SPI display at the soldering iron and live WebSocket browser mirrors.
Flagship Architecture
Xiaozhi Smart Electronics Workbench
The Story: When I'm hands-deep in solder fumes holding a 350°C iron and tweezers, I can't touch a keyboard or mouse to look up pinouts. I built this workbench companion so intelligence lives right at eye level, listening through MEMS microphones and rendering compact, high-contrast pinouts on dedicated hardware displays.
| Parameter | Engineering Specification | Design Notes |
|---|---|---|
| Host Compute | Ubuntu Linux x86_64, 4GB RAM | Systemd daemon with Nginx reverse proxy |
| Edge Processor | ESP32-S3 (Xtensa Dual-Core 240MHz) | 512KB SRAM + 8MB PSRAM + 16MB Flash |
| Audio Codec & Mic | INMP441 MEMS I2S + MAX98357A DAC | 24-bit 16kHz DMA stream; 60ms Opus frames |
| LLM Transcription | Groq Whisper Large-v3 Turbo | LPU inference latency < 180ms |
| Synthesis (TTS) | ElevenLabs Streaming PCM (Voice x4eeaCQG3dqOPKBvawgo) | Automatic fallback to Edge-TTS on 401/429 |
| Display Bus | SPI @ 40MHz (ILI9341) + ST7701S 16-bit RGB | Dual-framebuffer zero-tearing direct DMA |
| Agent Tool Protocol | MCP JSON-RPC 2.0 (9 Exposed Endpoints) | Standardized bidirectional tool execution |
| Signal Name | Wire Color | Source Pin | Target Pin | Protocol / Notes |
|---|---|---|---|---|
| 3.3V Power Rail | Red | 3V3 | ILI9341 VCC / Mic VDD | Regulated 3.3V, ≥ 500mA decoupled with 10µF cap |
| Ground Rail | Black | GND | Common Ground | Single point star ground for clean I2S noise floor |
| SPI Clock (SCLK) | Orange | GPIO 18 | ILI9341 CLK | SPI High-speed 40MHz SPI master clock |
| SPI Data (MOSI) | Green | GPIO 23 | ILI9341 MOSI | SPI 320x240 bitmap streaming output |
| SPI Chip Select | Yellow | GPIO 5 | ILI9341 CS | SPI Active-low display enable |
| SPI Data/Command | Cyan | GPIO 21 | ILI9341 D/C | SPI High = Data byte, Low = Command byte |
| I2S Bit Clock (BCLK) | Orange | GPIO 44 | INMP441 SCK & Amp BCLK | I2S 16kHz × 32 bits = 512kHz square wave |
| I2S Word Select (WS) | Green | GPIO 43 | INMP441 WS & Amp LRCK | I2S Left/Right frame synchronization (16kHz) |
| I2S Data In (DIN) | Blue | GPIO 2 | INMP441 SD Out | I2S Low-noise MEMS microphone stream input |
| I2S Data Out (DOUT) | Violet | GPIO 19 | MAX98357A DIN | I2S Streaming PCM audio playback to 3W speaker |
- Native MCP JSON-RPC 2.0 Gateway: 9 operational agent tools exposed directly to Claude and Antigravity IDE (display_on_desk, query_inventory, log_note, read_telemetry).
- Dual-Tier Display Routing: Parses AI responses into compact solder pinout bullets (ILI9341 LCD) and rich interactive Feynman commentary (7" Kiosk).
- Sub-400ms Pipeline: Hardware-accelerated Groq LPU routing coupled with asynchronous non-blocking SQLite persistence.
Raspberry Pi 4B
ESP32-S3/P4
MCP 2.0
ILI9341 SPI
FastAPI
Groq LPU