# SkyLogic AeroAlign - 3D Printable Parts

**Status**: Placeholder documentation for Phase 1 design
**Design Tool**: FreeCAD 0.20+ (open-source parametric CAD)
**Export Format**: STL for 3D printing

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## Overview

This directory will contain all 3D printable parts for the SkyLogic AeroAlign wireless RC telemetry system. Parts are designed to fit within 200mm × 200mm × 200mm build volume (compatible with Ender 3, Prusa Mini, Bambu Lab P1P).

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## Part List

### Sensor Housing (Required)

1. **sensor_housing_top.stl**
   - Dimensions: 38mm × 28mm × 8mm
   - Features: Clip-on IMU holder, LED window, USB-C port access
   - Material: PLA or PETG
   - Infill: 20% cubic
   - Support: None required (designed for support-free printing)
   - Print time: ~45 minutes

2. **sensor_housing_bottom.stl**
   - Dimensions: 38mm × 28mm × 10mm
   - Features: Battery compartment (400mAh LiPo), 4× M2 screw holes
   - Material: PLA or PETG
   - Infill: 20% cubic
   - Support: Minimal (<10% volume)
   - Print time: ~1 hour

### Control Surface Clips (Choose appropriate size)

3. **clip_3mm.stl**
   - For 3mm thick control surfaces (small foam ailerons)
   - Spring clip design, PETG recommended for flexibility
   - Rubber pad inserts: 6mm diameter × 1mm thick

4. **clip_5mm.stl**
   - For 5mm thick control surfaces (standard balsa elevators)
   - Most common size for RC models

5. **clip_8mm.stl**
   - For 8mm thick control surfaces (large rudders, thicker wings)
   - Reinforced jaw design

### Multi-Sensor Expansion (Phase 8)

6. **wing_surface_mount_adjustable.stl**
   - 3-point contact clip for wing root attachment
   - Adjustable height: 10-20mm
   - Dimensions: 120mm × 80mm × 35mm
   - Rubber pad inserts: 6× pads (front, mid, rear)

7. **wing_surface_mount_50mm.stl**, **wing_surface_mount_100mm.stl**, **wing_surface_mount_150mm.stl**
   - Fixed-size wing clips for 50mm, 100mm, 150mm chord wings
   - Faster to print than adjustable version

8. **control_surface_clip_springloaded_3mm.stl**
   - Spring-loaded clip (PETG material required)
   - Grips trailing edge securely without adhesive

9. **hinge_line_mount_universal.stl**
   - L-shaped bracket for hinge line attachment
   - Measures differential directly at pivot point

10. **magnetic_mount_base.stl**
    - Self-adhesive metal plate (3M VHB backing)
    - Dimensions: 20mm × 10mm × 1mm
    - Pairs with sensor_housing_magnetic_top.stl

11. **sensor_housing_magnetic_top.stl**
    - Variant of sensor_housing_top.stl with magnet pockets
    - 2× N52 neodymium magnets (10mm diameter × 2mm thick)

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## Print Settings

### Recommended Settings (FDM)

| Parameter | PLA (Housing) | PETG (Clips) | TPU (Optional) |
|-----------|---------------|--------------|----------------|
| Layer Height | 0.2mm | 0.2mm | 0.25mm |
| Infill | 20% cubic | 30% grid | 40% gyroid |
| Wall Count | 3 | 4 | 3 |
| Top/Bottom Layers | 4 | 5 | 4 |
| Print Speed | 60mm/s | 45mm/s | 30mm/s |
| Nozzle Temp | 205°C | 235°C | 215°C |
| Bed Temp | 60°C | 80°C | 60°C |
| Support | None/Tree | Tree | None |

### Tolerances

- Screw holes: 2.2mm diameter (for M2 screws, accounts for ±0.2mm print variance)
- Clip jaw opening: ±0.3mm clearance for control surfaces
- Snap-fit features: 0.5mm interference for secure assembly

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## Assembly Notes

### Sensor Housing Assembly

1. **Insert Electronics**:
   - ESP32-C3 DevKit in top shell
   - MPU6050 IMU aligned with housing center
   - LiPo battery in bottom shell compartment

2. **Close Housing**:
   - Align top and bottom shells
   - Insert 4× M2×6mm screws through bottom, into top
   - Tighten until snug (do not overtighten, plastic may crack)

3. **Attach Clip**:
   - Choose appropriate clip size (3mm, 5mm, or 8mm)
   - Slide clip onto housing rails
   - Apply rubber pads to clip jaws (prevent surface scratches)

### Magnetic Mount Assembly (Multi-Sensor)

1. **Prepare Base Plate**:
   - Clean model surface with isopropyl alcohol
   - Apply 3M VHB tape to magnetic_mount_base.stl
   - Press firmly onto wing/elevator (wait 24h for full adhesion)

2. **Install Magnets**:
   - Insert 2× N52 magnets into sensor_housing_magnetic_top.stl pockets
   - Ensure correct polarity (N-S attracts base plate magnets)
   - Secure with CA glue if loose

3. **Attach Sensor**:
   - Snap sensor housing onto magnetic base (2-second operation)
   - Magnets hold ~500g force (sufficient for workshop use)

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## Design Files (Source)

**FreeCAD Project Files** (for customization):
- `sensor_housing.FCStd` - Parametric housing design
- `clips_library.FCStd` - Clip variants (3mm, 5mm, 8mm)
- `wing_mounts.FCStd` - Multi-sensor expansion mounts

**To Export STL**:
1. Open `.FCStd` file in FreeCAD
2. Select part in tree view
3. File → Export → Mesh Formats (.stl)
4. Settings: Deviation 0.1mm, Max mesh angle 20°

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## Testing and Validation

### Phase 2 Validation Tasks

- [ ] T058: Print sensor housing on Ender 3 (verify fit and tolerance)
- [ ] T059: Test print on Prusa Mini and Bambu Lab P1P (cross-printer compatibility)
- [ ] T060: Create assembly guide with photos
- [ ] T061: Document print settings for all STL files
- [ ] T062: Weigh assembled nodes (verify <25g per node)

### Durability Testing

- [ ] T080: Drop test from 1 meter onto hard surface (10 times)
- [ ] T123: Test specialized mounts on RC model (foam wing, balsa surfaces)

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## Material Costs

- PLA filament: ~20g per sensor housing = $0.40 @ $20/kg
- PETG filament: ~10g for 6 clips = $0.25 @ $25/kg
- **Total material cost per system**: $0.65 (negligible)

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## Printer Compatibility

Tested on:
- [ ] Creality Ender 3 V2 ($200, 220mm build volume)
- [ ] Prusa Mini+ ($400, 180mm build volume)
- [ ] Bambu Lab P1P ($500, 256mm build volume)
- [ ] Anycubic Kobra ($250, 220mm build volume)

**Minimum Requirements**:
- Build volume: 200mm × 200mm × 200mm
- Layer height: 0.2mm capability
- Filament: PLA or PETG compatible

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## Alternative: 3D Printing Services

If you don't own a 3D printer:
- **3D Hubs / Craftcloud**: Upload STL, get quotes from local printers ($10-20 per set)
- **Shapeways**: Online 3D printing service (higher cost, premium materials)
- **Local Makerspaces**: Many libraries and hackerspaces offer 3D printing for members

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## License

Hardware designs (STL files, FreeCAD sources) are licensed under:
**Creative Commons BY-SA 4.0**

You are free to:
- Share: Copy and redistribute in any medium or format
- Adapt: Remix, transform, and build upon the material

Under the following terms:
- Attribution: Give appropriate credit to SkyLogic AeroAlign project
- ShareAlike: Distribute derivatives under same license

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## Roadmap

**Phase 1 (Current)**: Design sensor housing and basic clips
**Phase 2**: Validate print quality on 3 printer brands
**Phase 8**: Design specialized mounts for 8-sensor expansion

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*SkyLogic AeroAlign - Precision Grounded.*