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Subscale Satellite Documentation

AER813 Capstone project - subscale satellite test apparatus documentation site.

Project Structure

  • docs/ - Zensical documentation source (Markdown)
  • docs/electrical/ - Electrical systems documentation
  • docs/electrical/diagrams/ - D2 diagram source files + rendered SVGs
  • docs/project/ - BOM, procurement tracking

Diagram Workflow

D2 Diagrams

Source .d2 files live in docs/electrical/diagrams/. Rendered SVGs are committed alongside them.

To render all diagrams: 

cd docs/electrical/diagrams
for f in *.d2; do d2 --layout elk --theme 0 "$f" "${f%.d2}.svg"; done

D2 gotchas learned the hard way: - # starts a comment - always quote labels containing # (e.g., d1: "TMC2209 #1") - () defines shapes - always quote labels containing parentheses - -> in labels gets parsed as connections - quote or rephrase - Don't add child nodes to containers after the container block closes - Always use --layout elk for best results on block diagrams

Skills

Diagram generation skills are saved at: - /Users/zeul/.claude/skills/d2-diagrams/SKILL.md - D2 syntax reference and generation guide - /Users/zeul/.claude/skills/aer813-capstone/references/chart-making.md - SVG style guide (PDR color palette)

Serving

.venv/bin/zensical serve

Port 8813 by default.

Google Sheet BOM

  • Spreadsheet ID: 1E1N-070xhcGK5FVkjd1sBZlGc8as569FgII3UE0jsTo
  • Subscale Satellite BOM tab (rows 4-24 original, 27-40 additional wiring/discrete)
  • Testing Apparatus BOM tab (rows 4-17 original, 19-26 additional wiring/discrete)

Key Component Reference

GEO-DUDe (12V System)

  • 12V 600W PSU, 50A max
  • 120V AC via 3-wire 15A slip ring
  • Two independent identical 5-DOF arms, 5 servos per arm, 10 PWM servos total (3 voltage rails: 12V, 7.4V, 5V)
  • PCA9685 I2C PWM driver (all 10 servo signals): Ch 0-4 Arm 1, Ch 5-9 Arm 2, Ch 14 MACE ESC
  • 10 limit switches (one per joint per arm), connected to Pi GPIO with internal pull-ups
  • 3 buck converters (7.4V elbow, 5V Pi, 5V servo)
  • 1 merged fuse board (perfboard, 10 fuses total: 8A base x2, 8A shoulder x2, 5A elbow x2, 3A wrist rot x2, 3A wrist pan x2)
  • 40A toggle switch for manual servo power control (Jtron Waterproof DC12V 40A/24V 20A, replaces relay + transistor driver)
  • 30A inline blade fuse on 12V trunk
  • 6A slow-blow AC fuse on mains hot (must be AC-rated, not blade fuse)
  • Trunk wiring: 2x 16 AWG parallel (~24A capacity, 30A fuse)
  • Realistic load ~17A through toggle switch, stall worst-case ~42A
  • Cyrico blade fuse block used for buck converter inputs and fan

Gimbal (24V System)

  • 24V 480W PSU, 20A max
  • 4x TMC2209 stepper drivers (UART addressed, breadboard for logic/signal)
  • 4x NEMA 17 stepper motors (yaw, pitch, roll, belt)
  • ESP32 DOIT DevKit V1 (powered separately via 5V USB)
  • 12A main DC fuse, 14 AWG trunk
  • WiFi link to Raspberry Pi
  • Power wiring (VMOT, GND, motor outputs) via Wago lever connectors, NOT through breadboard (2A per motor exceeds breadboard contact rating)
  • Need to buy: screw terminals for breadboard (plug into breadboard, accept wire via screw)
  • TMC2209 drivers handle overcurrent protection (2A RMS limit), no per-motor fusing needed