PROJECT SPECIFICATION: CAT

Attribute	Specification
Codename:	Cyber Arm Terminal / The Gauntlet
Role:	Real-Time Deck & Home Assistant Satellite
Architecture:	Tri-Core Distributed System (Teensy 4.1 + XIAO Cluster)
Aesthetic:	Cyberpunk Safari (Muffinland: Sunflower Yellow/Raspberry Red)
User Profile:	Large Bodied Modder (Ergonomics for 325mm forearm)

1. HARDWARE MANIFEST & SEGMENTATION

Location: Distal forearm (closest to hand).
Core Logic:
- Master Host: Teensy 4.1 (600MHz Cortex-M7).
  - Role: Real-time OS, Audio Engine, UI Rendering, JPEG Decoding.
- Vision Node: Seeed Studio XIAO ESP32-S3 Sense.
  - Role: Ventral Camera (Live View), Digital Mic, Voice Wake-Word.
- Comms Node: Seeed Studio XIAO ESP32-C6.
  - Role: Zigbee Gateway, Matter, WiFi 6, BLE 5.3.
Sensors & Vision:
- Ventral Camera: OV2640 (on S3 Sense).
  - Placement: Underside of wrist (Facing palm).
  - Mode: "Live View" (MJPEG Stream to Round LCD).
- Microphone: Digital (on S3 Sense).
- Motion: Bosch BMI270 (6-Axis IMU).
- Environment: BME280 (Temp/Humidity/Pressure).
Illumination:
- Work Light: High-CRI 3W White LED.
- Inspection: 365nm UV LED (Leak detection).
Interface:
- Primary Display: 1.28" Round LCD (GC9A01) – "Gauge" Cluster & Camera Viewfinder.
- Secondary Display: 2.08" OLED (Terminal Output).
Haptics:
- Unit: Nexus 6P Vibration Module (Silent Alerts).

Location: Mid-forearm.
Matrix System:
- Driver: Seeed Studio XIAO RP2350.
  - Role: Dedicated PIO LED Driver (Slave to Teensy).
  - Optimization: 520KB RAM allows for complex multi-layer buffering.
- Display: Custom Fabricated LED Matrix (High Density).
  - Thermal: Bonded to Copper Shield via Silicone Pad.
Controls:
- 3x Toggle Switches (Power / Light / Silent).
- 2x Rotary Encoders (Volume / Scroll).

Location: Proximal forearm (near elbow joint).
Power Systems:
- Main Bank: 7x EVE ICR18650-20P (1S7P Parallel).
  - Capacity: ~24.5Ah (Max Discharge: 30A Fused).
- Management: 1x IP5328P USB-C PD Module.
  - Role: Single-point 18W Fast Charging & System Regulation.
- Step-Down: High-Efficiency Buck Converter (5V Rail).
Audio System:
- Module: MAX98357 I2S Amplifier (Digital Input for Zero Noise).
- Transducer: Salvaged Pixel/iPhone Speaker Module (Enclosed).
- Safety: 4Ω 2W Resistor in series (Physical Limiter to prevent blowout).
Connectivity:
- Hardline: GX12 Aviation Connector (RAV4 OBD / MIDI Out).

The arm is built in three distinct strata, designed for maximum thermal rejection in Georgia heat:

Layer 1: The Foundation (Inner Skin)
- Material: Top Grain Leather ("Skin Top") Inlay.
- Function: Electrical insulation & comfort barrier.
Layer 2: The Thermal Shield (Core)
- Material: 1.0mm Hand-Formed Copper Plate ("Vambrace").
- Fin Stack: Harvested Copper Fins, sweat-soldered to the elbow region.
- Component Mounting:
  - Method: M2.5 Brass Nuts sweat-soldered to the plate.
  - Interface: 1.5mm Silicone Thermal Pads compressed between PCB and Copper.
  - Targets: IP5328P, Buck Converter, RP2350.
- Grounding: "Star Ground" topology. Plate is grounded at one single point to act as a shield, not a conductor.
Layer 3: The Armor (Outer)
- Material: ASA (Acrylonitrile Styrene Acrylate).
- Finish: "Muffinland" color scheme (Yellow/Red); chemically smoothed.
- RF Safety: ASA standoffs lift the ESP32-C6/S3 antennas 5mm off the copper plate; Copper notched below antennas to prevent signal blocking.
- Venting: Aggressive "Gill" vents in Segment C to expose the soldered fins.

Cell Fusing: "Tesla Style" - Individual fuse wire links for each of the 7 cells to the positive bus bar.
Serviceability: All electronics are bolted to soldered brass standoffs (not glued), allowing for field repairs.
Audio Isolation: Analog Audio Ground is isolated from the Noisy Digital/Matrix Ground until the battery terminal to prevent buzzing.

Teensy 4.1: Main Firmware (C++).
- Pipeline: Decodes incoming MJPEG stream from S3 Sense and pushes to GC9A01 via DMA.
ESP32-C6: Runs Zigbee2MQTT / ESPHome bridge.
ESP32-S3 Sense: Runs Camera Stream & Voice Processing.
XIAO RP2350: Runs LED Matrix shaders (PIO/HSTX).