fixture_config.toml

# OpenFixture Configuration File
# TOML format for fixture generation parameters
#
# This file allows you to define project-specific fixture parameters
# Command-line arguments will override these settings
#
# Last Updated: February 15, 2026

# ============================================================================
# BOARD PARAMETERS
# ============================================================================
[board]
# PCB thickness in millimeters
# Standard values: 0.8, 1.0, 1.6, 2.0, 2.4
thickness_mm = 1.6

# Test point layer selection
# Options: "F.Cu" (front/top), "B.Cu" (back/bottom), "both" (both sides)
test_layer = "F.Cu"

# Override board revision (optional)
# If not set, reads from PCB file title block
# revision = "rev_01"

# ============================================================================
# TEST POINT DETECTION
# ============================================================================
[test_points]
# Pad types to include as test points
# SMD: Surface mount pads (designed test points)
# PTH: Plated through-hole pads (connector pins, component leads)
#      Note: PTH pads are only detected from components on the OPPOSITE side
#      Example: Testing from bottom → Only uses PTH from top-side components
#      Reason: Component body blocks access, pins accessible from other side
include_smd_pads = true
include_pth_pads = true

# Pad filtering
# - Pads with solder paste mask are excluded (unless on force_layer)
# - Pads on ignore_layer (Eco1.User) are excluded
# - Pads on force_layer (Eco2.User) are always included
# - Test Point symbols (TP*) from schematic are automatically included

# ============================================================================
# MATERIAL PARAMETERS
# ============================================================================
[material]
# Material thickness in millimeters
# Common acrylic: 2.45, 3.0, 4.0
# Common plywood: 3.0, 5.0
thickness_mm = 3.0

# Laser kerf compensation (handled in OpenSCAD)
# Typical: 0.1-0.2mm for acrylic
# kerf_mm = 0.125

# ============================================================================
# HARDWARE PARAMETERS
# ============================================================================
[hardware]
# Screw specifications (M3 recommended)
screw_diameter_mm = 3.0
screw_length_mm = 16.0

# Hex nut dimensions (M3 typical values)
nut_thickness_mm = 2.4
nut_flat_to_flat_mm = 5.45
nut_corner_to_corner_mm = 6.10

# Washer thickness (optional, for smoother hinge operation)
washer_thickness_mm = 1.0

# Pivot hole diameter (tight fit for alignment)
# Default: screw_diameter - 0.1
# For bushing: 5.12
pivot_diameter_mm = 2.9

# PCB support border width
# Ledge that holds PCB in place
border_mm = 0.8

# Pogo pin specifications
# Uncompressed length: Measured from receptacle base to pin tip (fully extended)
# 
# Common pogo pin series:
# - P75-A2/B1: 16.5mm (budget-friendly, $0.16-0.22/pin, 10k-50k cycles)
# - P75-E2: 24.0mm (crown tip, general purpose, good for 0402-0805 pads)
# - Fixtest 100: 29.6mm (professional grade, ~$3.50/point, 100k+ cycles)
#
# Select based on your application:
# - Prototype/low-volume: P75 series (16-24mm)
# - Production/high-volume: Fixtest 100 (29.6mm)
#
pogo_uncompressed_length_mm = 16.0  # Default for P75-A2/B1

# Examples for other pogo pin models:
# pogo_uncompressed_length_mm = 24.0   # For P75-E2 (crown tip, 24mm)
# pogo_uncompressed_length_mm = 29.6   # For Fixtest S 100.00-L receptacle
# pogo_uncompressed_length_mm = 20.0   # For P75-D2 (flat tip, 20mm)

# Advanced pogo pin parameters (handled automatically by OpenSCAD)
# pogo_compression_mm = 1.0-1.5  # Target compression (optimal contact force)
# pogo_diameter_mm = 1.02        # Pin barrel diameter (P75 series standard)
# pogo_receptacle_diameter_mm = 1.5  # Receptacle hole diameter

# ============================================================================
# LAYER CONFIGURATION
# ============================================================================
[layers]
# Force include layer - pads on this layer are always test points
# Default: Eco2.User
force_layer = "Eco2.User"

# Ignore layer - pads on this layer are never test points
# Default: Eco1.User
ignore_layer = "Eco1.User"

# ============================================================================
# BRANDING / LOGO
# ============================================================================
[logo]
# Enable logo on fixture top plate
enable = true

# Logo file path (DXF format recommended for laser cutting)
# Absolute path or relative to OpenFixture support directory
# Default: "./osh_logo.dxf" (Open Source Hardware logo)
file = "./osh_logo.dxf"

# Logo scale factors (X, Y, Z)
# Adjust to fit your logo size
# Default OSH logo uses: 0.15, 0.15, 1.0
scale_x = 0.15
scale_y = 0.15
scale_z = 1.0

# Logo position offset (X, Y, Z)
# Translation applied after scaling
# Default OSH logo uses: -72, -66, 0 (centers the logo)
offset_x = -72.0
offset_y = -66.0
offset_z = 0.0

# Examples:
# Company logo (larger): scale_x=0.25, scale_y=0.25, offset_x=-100, offset_y=-80
# Project badge (small): scale_x=0.1, scale_y=0.1, offset_x=-50, offset_y=-50
# Disable logo: enable = false

# ============================================================================
# OUTPUT SETTINGS
# ============================================================================
[output]
# Output directory (relative to project)
directory = "fixture"

# Generate additional files
export_test_cut = true       # Small test piece for material verification
export_3d_preview = true     # PNG rendering of assembled fixture
export_validation = true     # Track overlay for test point verification

# ============================================================================
# ADVANCED SETTINGS
# ============================================================================
[advanced]
# Enable verbose logging (creates detailed log file)
verbose_logging = false

# Coordinate correction offsets (fine-tune alignment)
# Usually not needed, but can compensate for systematic errors
tp_correction_offset_x = 0.0
tp_correction_offset_y = 0.0

# Minimum angle for pogo pin contact (degrees)
# Closer to 90° is better for reliable contact
min_pogo_contact_angle = 89.5

# ============================================================================
# EXAMPLE CONFIGURATIONS
# ============================================================================
# Copy and modify these values in the active sections above to match your needs
#
# Standard: 1.6mm PCB + 3mm acrylic + M3x16 screws
# Thin PCB: 0.8mm PCB + 2.45mm acrylic + M3x14 screws  
# Heavy-duty: 2.0mm PCB + 5mm plywood + M3x20 screws + 1.5mm border

# ============================================================================
# NOTES
# ============================================================================
#
# Material Thickness:
#   - Measure actual material with calipers
#   - Laser-cut materials can vary ±0.1mm
#   - Use test cut to verify fit
#
# Screw Length:
#   - Measure threaded length only (not head)
#   - Must be: screw_length >= material_thickness + pcb_thickness + nut_thickness + 3mm
#   - Excess length improves clamping but requires more clearance
#
# Nut Dimensions:
#   - Measure with calipers (varies by manufacturer)
#   - Flat-to-flat: Across parallel sides
#   - Corner-to-corner: Across diagonal
#   - Undersized holes can be carefully drilled out
#
# Pogo Pins:
#   - Uncompressed length: From receptacle top to pin tip (fully extended)
#   - Target compression: 1.0-1.5mm typical for good contact force
#   - Spring force: 50-100g per pin recommended (too many = hard to close fixture)
#   
#   P75 Series (Budget-Friendly):
#     • Barrel diameter: 1.02mm (0.040")
#     • Length options: 16.5-33.3mm (A2/B1/D2/D3/E2/F1/G2 variants)
#     • Price: $0.16-0.22 per pin
#     • Cycle life: 10,000-50,000 cycles
#     • Best for: Prototypes, low-volume testing
#     • Tip styles:
#       - P75-A2 (16.5mm, sharp point): Very small pads <0.5mm
#       - P75-B1 (16.5mm, rounded): Through-hole connector pins
#       - P75-E2 (24mm, crown): General purpose, 0402-0805 pads
#       - P75-D2/D3 (20-22mm, flat): Large pads, high current >1A
#     • Source: https://www.digole.com/index.php?categoryID=115
#   
#   Fixtest Series 100 (Professional Grade):
#     • Receptacle length: 29.6mm (S 100.00-L)
#     • Material: Beryllium copper, gold plated contacts
#     • Price: ~$3.50 per test point (receptacle + probe)
#     • Cycle life: 100,000+ cycles
#     • Current rating: 3A continuous
#     • Operating temp: -40°C to +125°C
#     • Best for: Production testing, high-volume, automated test
#     • Source: https://www.tme.eu/ (TME.eu - Fixtest series 100)
#   
#   Two-Part System:
#     1. Receptacle (holder): Press-fit or solder into fixture plate
#     2. Probe pin (plunger): Spring-loaded, replaceable wear component
#     Keep spare probe pins - tips wear from repeated contact and arcing
#
# Test Points:
#   Selection algorithm (in order of precedence):
#     1. Force layer (Eco2.User): ALWAYS included, overrides all rules
#     2. Ignore layer (Eco1.User): ALWAYS excluded
#     3. Paste mask: Pads with paste mask are excluded
#     4. Pad type filtering (configurable):
#        • SMD pads: Include if include_smd_pads=true
#        • PTH pads: Include if include_pth_pads=true
#          - PTH Opposite Side Rule: Only PTH from opposite side components
#          - Example: Test from bottom → Only PTH from top components
#          - Reason: Component body blocks same-side access
#     5. Layer: Must be on selected test layer (F.Cu or B.Cu)
#   
#   Minimum pad size: 0.5mm diameter for reliable probing
#   Verify with track.dxf overlay: Import into KiCAD to check alignment
#   Design tip: Remove solder mask AND paste mask from test pads