KiCad Auto Designer

An intelligent PCB layout automation plugin for KiCad 9.0 that automatically places components using connectivity-aware algorithms, creating professional, compact layouts optimized for signal integrity and manufacturability.

Features

• 🔌 Connectivity-Aware Placement: Groups components by electrical function and signal flow

  • Power management subsystem
  • Wireless/RF components isolation
  • Processor and support circuitry
  • Motor control circuits
  • Interface connectors

• 📐 Professional Layout Algorithms:

  • Square-aspect-ratio shelf packing for efficient space utilization
  • 2D local-search compaction for optimal density
  • Force-directed relaxation to eliminate overlaps
  • Intelligent edge placement for connectors and antennas

• 🎯 Smart Component Recognition:

  • Automatic connector detection (USB, UART, JTAG, power jacks)
  • Antenna component identification
  • Reference designator pattern matching
  • Component grouping by electrical relationships

• ⚡ Optimization Features:

  • Minimizes trace lengths between connected components
  • Maintains proper clearances and spacing
  • Automatically creates board edge cuts
  • Centers layout on board for symmetry

Installation

Method 1: Direct Installation

1. Locate your KiCad scripting plugins directory:

   • macOS: ~/Documents/KiCad/9.0/scripting/plugins/
   • Linux: ~/.config/kicad/9.0/scripting/plugins/
   • Windows: %APPDATA%\kicad\9.0\scripting\plugins\

2. Copy kicad_auto_designer.py to the plugins directory

3. Restart KiCad PCB Editor or refresh plugins

Method 2: Symbolic Link (Development)

# macOS/Linux
ln -s /path/to/kicad_auto_designer.py ~/Documents/KiCad/9.0/scripting/plugins/

# Windows (Command Prompt as Administrator)
mklink "%APPDATA%\kicad\9.0\scripting\plugins\kicad_auto_designer.py" "C:\path\to\kicad_auto_designer.py"

Usage

1. Open your PCB file in KiCad PCB Editor
2. Navigate to Tools → External Plugins → KiCad Auto Designer
3. Click Run to execute automatic layout
4. The plugin will:
   • Group components by connectivity and function
   • Pack them into a compact rectangular layout
   • Place connectors and antennas at board edges
   • Create edge cuts boundary
   • Center the entire layout

Before Running

• Ensure all components are imported from schematic
• Set approximate board size (can be adjusted after)
• Save your work (plugin creates a backup state)

After Running

• Review component placement
• Fine-tune specific positions if needed
• Run DRC (Design Rules Check) to verify clearances
• Proceed with routing

How It Works

Layout Algorithm

1. Component Categorization:

   Power Management → Wireless → Processor → Motor Control → Interfaces → Passives
   

2. Packing Strategy:

   • Calculates target width for square-aspect layout
   • Uses Next-Fit Decreasing Height (NFDH) shelf packing
   • Tests component rotations for better fit
   • Compacts rows and columns

3. Optimization Passes:

   • 2D Compaction: 80 iterations of local moves and swaps
   • Force-Directed Relaxation: 20 iterations with 0.05mm minimum spacing
   • Overlap Resolution: Greedy pairwise collision detection

4. Edge Placement:

   • Antenna → Bottom-left corner (isolated)
   • Power connectors → Bottom edge (0° orientation)
   • Data connectors → Right edge (90° orientation)
   • 4mm board margin, 2mm component spacing

5. Finalization:

   • Center layout on board
   • Create rectangular edge cuts with 2mm margin
   • Refresh display

Configuration

Edit these parameters in kicad_auto_designer.py:

# Spacing and margins
min_spacing_nm = int(0.01 * 1_000_000)  # 0.01mm minimum spacing
margin_nm = int(1 * 1_000_000)          # 1mm board margin

# Compaction iterations
max_iterations = 80                      # 2D compaction passes

# Relaxation parameters
relax_iterations = 20                    # Force-directed iterations
min_spacing_relax = 0.05                 # 0.05mm spacing target

# Edge placement
board_margin_mm = 4.0                    # 4mm from edge
edge_spacing_mm = 2.0                    # 2mm between edge components

Component Recognition Patterns

Connectors

• USB: USB, J_USB
• UART: UART, SERIAL, TX, RX
• JTAG: JTAG, SWD, DEBUG
• Power: BARREL, JACK, PWR, VIN
• GPIO: GPIO, HEADER, PIN

Special Components

• Antenna: ANTENNA, ANT, U2
• Wireless: U1, ESP, BLE, WIFI
• Processor: U4, MCU, CPU
• Motor: DRV, MOTOR, U3

Requirements

• KiCad Version: 9.0 or later
• Python: 3.8+ (bundled with KiCad)
• Dependencies:
  • pcbnew (KiCad Python API)
  • wx (GUI dialogs)
  • Standard library: math, random

Known Limitations

• Does not consider existing traces (place components before routing)
• Manual DRC verification recommended after placement
• Complex boards (>100 components) may require multiple runs
• Net-aware optimization is connectivity-based, not electrical rules-aware

Roadmap

• Net-length optimization for matched pairs
• Layer-aware component placement
• Thermal via placement for power components
• Interactive placement with user hints
• Undo/redo support
• Batch processing for multiple boards
• Custom component grouping rules

Contributing

Contributions are welcome! Areas for improvement:

1. Algorithm Enhancements: Better packing, net-aware placement
2. Component Recognition: More patterns, ML-based classification
3. Optimization: Performance improvements for large boards
4. Testing: Test cases for various board types
5. Documentation: Usage examples, video tutorials

License

This project is licensed under the GNU General Public License v3.0 (GPLv3) - see the LICENSE file for details.

Author

Created for professional PCB design automation. For issues, feature requests, or contributions, please use the GitHub issue tracker.

Acknowledgments

• KiCad development team for the excellent Python API
• Shelf packing algorithms from computational geometry literature
• Force-directed layout concepts from graph theory

---

⚡ Happy Auto-Designing! 🚀