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PROJECT SPECIFICATION: ANGUS

Attribute Specification
Codename: The Servo-Skull / Machine Spirit
Role: Autonomous Workshop Assistant
Architecture: Remote-Actuated Serial Manipulator (Chain Drive)
Aesthetic: Heavy Industrial / Scavenger (Exposed Metal, Grease, ASA)
User Profile: Workshop Companion (Stationary Base)

1. HARDWARE MANIFEST & SEGMENTATION

Segment A: The Base ("The Foundation")

  • Role: Mass Anchor & Power Plant.
  • Power System (UPS):
    • Unit: Geekworm X728 (Max 5.1V 6A).
    • Reserve: 4x Samsung INR18650-13Q (Parallel).
  • Motion Core (High Torque):
    • Motors: 3x NEMA 17 Steppers (4S42Q-T03240S).
    • Reduction: 5:1 Planetary Gearbox (Required).
    • Drivers: 3x TMC2209 SilentStepSticks.
    • Controller: Arduino UNO / Nano (GRBL Firmware).
    • Output: #25 Steel Sprockets (10T).
  • Homing System (Hard Stops):
    • Sensors: 3x KW12-3 Micro Limit Switches (The classic ones with the metal lever).
    • Placement:
      • Base Pan: Switch mounted on the rear of the turntable.
      • Shoulder: Switch mounted on the Aluminum Core where the arm folds down.
      • Elbow: Switch mounted inside the joint.
    • Function: "Zero" is physically defined by the arm hitting these switches.

Segment B: The Arm ("The Chain-Link Manipulator")

  • Core Structure: Aluminum Flat Bar (20mm x 5mm).
  • Transmission: ANSI #25 Roller Chain.
  • Physics Optimization:
    • Gravity Springs: Passive extension springs (Critical for lifting the head).
    • Chain Tensioners: Spring-loaded "Derailleur" arms.
  • Zero Position (The "Fold"):
    • The "Resting State" is now simply: All joints retracted until they hit their Limit Switches.
    • No complex "Mag-Dock" needed (unless you want extra security). The switches define the park position.

Segment C: The Head ("The End Effector")

  • Mounting: Bolts to Aluminum Core via M2.5 Rubber Silent Blocks.
  • The Stack:
    • Top: WM8960 Audio HAT + Tall GPIO Header.
    • Middle: Raspberry Pi 4 (8GB) + Armor Heatsink.
    • Bottom: Geekworm X825 SSD Shield + Drevo X1 60GB SSD.
  • Senses:
    • Vision: XIAO S3 (Pilot) + Grove Vision AI V2 (Recognition).
    • Audio: 2x External "Sensor Pod" Ears (40mm Drivers in ASA Cups).

2. FABRICATION STRATEGY (The "Click" Method)

  • Switch Mounting:
    • Do not glue the switches. Use M2 bolts. You will need to adjust them slightly to get the perfect "Park" angle.
    • The Limit Switches should be wired as Normally Open (NO) to the Arduino CNC Shield (Pins 9, 10, 11).
  • Chain Drive:
    • Reduction: 20:1 Total (5:1 Gearbox * 4:1 Chain).
    • Sprockets: Steel 10T Driver / ASA 40T Driven.

3. WIRING & PIN MAP

  • Head Stack Conflict:
    • WM8960 Audio: Uses GPIO 18, 19, 20, 21.
    • X728 UPS: Remapped from GPIO 19 -> GPIO 27 (via config.txt).

4. SAFETY & LOGIC PROTOCOLS

  • Startup Sequence (Homing):
    1. ANGUS wakes up.
    2. Motors move slowly in reverse.
    3. Click (Base) -> Stop.
    4. Click (Shoulder) -> Stop.
    5. Click (Elbow) -> Stop.
    6. System sets coordinates to (0,0,0). Ready for work.
  • "Death Rattle" (Power Loss):
    • Hardware: 4700uF Capacitor Bank on 12V Rail.
    • Logic: AC Loss -> X728 Signal -> Arduino drives all motors "Home" (Reverse) until switches click -> System Off.