sl-mechanical
e22fd23f33
Add gopro_mount.scad with: - Standard GoPro 3-prong interface on top for HERO 5+ compatibility - T-slot 2020 clamp with M3 thumbscrew retention (no tools required) - Tilt mechanism: 0-90° with 15° detent angles (7 positions) - Integrated T-nut slides into rail groove - Rotation axis via M5 hinge pin with index-hole angle locking - Design supports flat-face-down printing, no supports needed Includes comprehensive BOM with: - Part specifications for base clamp and camera bracket - Fastener list and torque specs - Step-by-step assembly instructions - Tilt angle reference guide - Post-print finishing notes - Cable management guidance Co-Authored-By: Claude Haiku 4.5 <noreply@anthropic.com>
253 lines
9.2 KiB
Markdown
253 lines
9.2 KiB
Markdown
# GoPro 3-Prong T-Slot Sensor Rail Mount — BOM + Assembly
|
||
**Rev A — 2026-03-02 — sl-mechanical**
|
||
|
||
---
|
||
|
||
## System Overview
|
||
|
||
Universal GoPro HERO 5+ camera mount for sensor_rail.scad (T-slot 20×20 mm).
|
||
|
||
| Feature | Spec |
|
||
|---------|------|
|
||
| Camera interface | Standard GoPro 3-prong (HERO 5+) |
|
||
| Rail system | T-slot 2020 OpenBuilds / MISUMI compatible |
|
||
| Tilt range | 0° – 90° from horizontal |
|
||
| Tilt detents | 15° increments (0°, 15°, 30°, 45°, 60°, 75°, 90°) |
|
||
| Retention | M3 thumbscrew clamp (T-nut to rail) + M5 index pin (angle lock) |
|
||
| Weight | ~85 g (printed) + ~45 g (fasteners) |
|
||
|
||
---
|
||
|
||
## Design Features
|
||
|
||
- **Top mount:** Standard GoPro 3-prong interface — no custom adapters, works with any GoPro HERO 5+ compatible accessory.
|
||
- **Bottom clamp:** Integrated T-nut slides into rail T-groove; single M3 thumbscrew locks clamp to rail (no tools required).
|
||
- **Tilt mechanism:** Rotating bracket + M5 hinge pin; camera tilts 0°–90° and locks at 15° steps via M5 index holes.
|
||
- **Printability:** Both parts print flat-face-down, no support material required.
|
||
- **Compatibility:** Works with all SaltyLab / SaltyRover sensor_rail.scad mounts; positions camera anywhere along rail.
|
||
|
||
---
|
||
|
||
## Part A — Printed Components
|
||
|
||
### 1. Base Clamp (gopro_mount.scad, RENDER="base_stl")
|
||
|
||
**Purpose:** Holds T-nut in rail T-groove; provides rotation axis for camera bracket.
|
||
|
||
| Parameter | Value | Notes |
|
||
|-----------|-------|-------|
|
||
| Qty | 1 | Single part per mount |
|
||
| Material | PETG | 5 perimeters, 40% infill (gyroid) |
|
||
| Print size | ~45 × 35 × 28 mm | Flat-face-down (rail-side down) |
|
||
| Orientation | Rail bore facing DOWN | Supports natural bed adhesion |
|
||
| Support | None | Design allows direct print |
|
||
| Wall thickness | 4–5 mm minimum | Ensure M3 threads cut cleanly |
|
||
|
||
**Key features:**
|
||
- Integrated T-nut pocket (friction-fit to rail T-groove)
|
||
- M3 thumbscrew bore (perpendicular to T-nut, from outside rail face)
|
||
- M5 hinge-pin bore (passes through to camera bracket)
|
||
- 7 index holes (one for each tilt angle: 0°, 15°, 30°, 45°, 60°, 75°, 90°)
|
||
- Vent slots for weight reduction
|
||
|
||
---
|
||
|
||
### 2. Camera Bracket (gopro_mount.scad, RENDER="camera_bracket")
|
||
|
||
**Purpose:** Holds GoPro camera via 3-prong mount; rotates about M5 hinge pin.
|
||
|
||
| Parameter | Value | Notes |
|
||
|-----------|-------|-------|
|
||
| Qty | 1 | Single part per mount |
|
||
| Material | PETG | 4 perimeters, 30% infill |
|
||
| Print size | ~35 × 25 × 51 mm | Flat-face-down (prong-side down) |
|
||
| Orientation | GoPro prongs facing DOWN | Minimal post-processing |
|
||
| Support | None | Design supports printing without supports |
|
||
| Wall thickness | 3–4 mm | Adequate for M5 through-bore |
|
||
|
||
**Key features:**
|
||
- 3 cylindrical prong sockets (GoPro standard spacing)
|
||
- M5 hinge-pin bore (receives bolt from base)
|
||
- 1 index hole (aligns with base index holes at tilt angle)
|
||
- Lightweight design
|
||
|
||
---
|
||
|
||
## Part B — Fasteners & Hardware
|
||
|
||
All fasteners are stainless steel or zinc-plated for corrosion resistance.
|
||
|
||
| # | Spec | Qty | Use | Notes |
|
||
|---|------|-----|-----|-------|
|
||
| 1 | M3 × 12 SHCS | 1 | Thumbscrew — clamps T-nut to rail | or M3 cap screw with printed knob |
|
||
| 2 | M3 washer | 1 | Under thumbscrew head | standard flat washer |
|
||
| 3 | M5 × 25 SHCS | 1 | Hinge pin — camera bracket rotation axis | or M5 cap screw + lock washer |
|
||
| 4 | M5 washer | 2 | Hinge pin lock washers (each end) | prevents backlash |
|
||
| 5 | M5 lock nut | 1 | Hinge pin lock nut | nylon-insert preferred |
|
||
| 6 | M5 × 8 roll pin | 7 | Index pins — lock tilt angle | one for each 15° detent (0°–90°) |
|
||
|
||
---
|
||
|
||
## Installation & Assembly
|
||
|
||
### Step 1: Prepare T-slot Rail
|
||
|
||
1. Verify rail is clean (no burrs, chips).
|
||
2. Slide base clamp assembly onto rail from above (rail face toward clamp bore).
|
||
3. Align T-nut pocket with T-slot T-groove (groove faces inward).
|
||
|
||
### Step 2: Clamp Base to Rail
|
||
|
||
1. Insert M3 thumbscrew through rail outer face, through the T-nut pocket.
|
||
2. Tighten **finger-tight** first (do not overtighten — rail will deform).
|
||
3. Verify clamp is centered on rail (equal gap on both sides).
|
||
4. Tighten to **hand-tight** (≈2 N·m for M3).
|
||
|
||
### Step 3: Assemble Hinge & Camera Bracket
|
||
|
||
1. Slide M5 × 25 bolt through base clamp hinge bore (horizontal, perpendicular to rail).
|
||
2. Mount camera bracket on bolt (prong-side facing camera direction).
|
||
3. Add M5 washers at both bolt ends.
|
||
4. Tighten M5 lock nut to **hand-tight** (≈5 N·m).
|
||
- Bolt should rotate smoothly but without play.
|
||
- If bracket binds, loosen slightly; if too loose, add second lock washer.
|
||
|
||
### Step 4: Mount GoPro Camera
|
||
|
||
1. Rotate camera bracket to desired tilt angle (0°, 15°, 30°, etc.).
|
||
2. Align index hole on bracket with corresponding hole on base clamp.
|
||
3. Insert M5 × 8 roll pin into aligned holes (pushes in snugly, no tools needed).
|
||
4. Verify pin locks camera position (should not rotate when pin is seated).
|
||
5. Slide GoPro onto 3 prongs until camera contacts mount.
|
||
|
||
### Step 5: Cable Management
|
||
|
||
- Route camera USB/HDMI cable down rail (behind robot).
|
||
- Use cable tie on thumbscrew pocket if additional restraint needed.
|
||
|
||
---
|
||
|
||
## Tilt Angle Detents
|
||
|
||
The 15° step gives 7 fixed positions within 0°–90° range:
|
||
|
||
| Tilt Index | Angle | Use case |
|
||
|------------|-------|----------|
|
||
| 1 | 0° | Horizontal (level with horizon) |
|
||
| 2 | 15° | Slight upward tilt |
|
||
| 3 | 30° | Moderate upward tilt |
|
||
| 4 | 45° | Balanced forward-up tilt |
|
||
| 5 | 60° | Steep upward tilt |
|
||
| 6 | 75° | Nearly vertical forward |
|
||
| 7 | 90° | Straight vertical (zenith) |
|
||
|
||
To change tilt:
|
||
1. Push on camera bracket to rotate (index pin will pop out if at end of rotation).
|
||
2. Align new index hole.
|
||
3. Re-insert index pin.
|
||
|
||
---
|
||
|
||
## Fastener Torque Spec
|
||
|
||
| Fastener | Size | Torque | Note |
|
||
|----------|------|--------|------|
|
||
| M3 thumbscrew | M3 × 12 | 2 N·m | Hand-tight; over-tightening deforms rail |
|
||
| M5 hinge pin | M5 × 25 | 5 N·m | Smooth rotation, no play |
|
||
| M5 lock nut | M5 | 2.5 N·m | After initial tightening, verify free rotation |
|
||
|
||
---
|
||
|
||
## Post-Print Finishing
|
||
|
||
### Base Clamp
|
||
- **Support removal:** No supports needed.
|
||
- **Bore prep:** If M3 bore is rough, ream with M3 hand reamer (¼ turn only).
|
||
- **T-nut pocket:** Smooth with fine sandpaper if needed (must slide smoothly into groove).
|
||
|
||
### Camera Bracket
|
||
- **Support removal:** No supports needed.
|
||
- **Prong sockets:** Clean with compressed air; verify no strands block GoPro prongs.
|
||
- **Index hole:** Verify M5 bore is clear (small drill bit can clear if needed).
|
||
|
||
---
|
||
|
||
## Mass Estimate
|
||
|
||
| Component | Material | Est. Mass |
|
||
|-----------|----------|-----------|
|
||
| Base clamp | PETG | ~35 g |
|
||
| Camera bracket | PETG | ~28 g |
|
||
| M3 thumbscrew | Stainless | ~2 g |
|
||
| M5 hinge bolt + nut | Stainless | ~6 g |
|
||
| M5 index pins (×7) | Steel | ~4 g |
|
||
| **Total (without camera)** | | **~75 g** |
|
||
| **Total (with GoPro HERO)** | | **~250 g** |
|
||
|
||
---
|
||
|
||
## Mounting Position Recommendations
|
||
|
||
### On sensor_rail.scad vertical rail
|
||
|
||
| Position | Z height | Use |
|
||
|----------|----------|-----|
|
||
| Below sensor head | 700–800 mm | Forward-facing wide-angle view |
|
||
| Mid-rail | 400–500 mm | Side-looking perspective |
|
||
| Above base plate | 100–200 mm | Ground-level or low-angle view |
|
||
|
||
Index holes on rail face every 25 mm; position bracket at any height (friction-fit with T-nut + thumbscrew).
|
||
|
||
### On payload_bay_rail.scad (horizontal rail)
|
||
|
||
Mount horizontally by:
|
||
1. Rotate entire assembly 90° (rail runs front-to-back).
|
||
2. Tilt camera bracket 0°–90° to point downward or forward.
|
||
3. Good for payload bay documentation (downward view) or forward obstacle detection.
|
||
|
||
---
|
||
|
||
## Storage & Maintenance
|
||
|
||
- **Store bracket vertical** (prongs up) to avoid stress on sockets.
|
||
- **Clean prongs** after each field session (dust prevents secure seating).
|
||
- **Verify index pin seating** before each deployment (pin can loosen if rattled).
|
||
- **Check thumbscrew** monthly (re-tighten if rail has shifted).
|
||
|
||
---
|
||
|
||
## Design Notes for Future Revisions
|
||
|
||
- **Optional:** Add detent detents (spring-loaded ball bearing pockets) at index holes for positive clicks.
|
||
- **Optional:** Add strap attachment points on base clamp for secondary safety line.
|
||
- **Alternative bracket:** Straight vertical bracket (0° fixed) for weight-optimized variant.
|
||
- **Camera variants:** Compatibility with GoPro Session (action cam) and DJI Osmo Action (different prong patterns) would require bracket redesign.
|
||
|
||
---
|
||
|
||
## Files
|
||
|
||
| File | Purpose |
|
||
|------|---------|
|
||
| `gopro_mount.scad` | OpenSCAD parametric model (3 RENDER variants) |
|
||
| `gopro_mount_BOM.md` | This document |
|
||
| `sensor_rail.scad` | Parent T-slot rail system (dependency) |
|
||
| `sensor_rail_brackets.scad` | Additional rail bracket options |
|
||
|
||
---
|
||
|
||
## Assembly Checklist
|
||
|
||
- [ ] Print base clamp (PETG, 45 × 35 × 28 mm, flat-side-down)
|
||
- [ ] Print camera bracket (PETG, 35 × 25 × 51 mm, flat-side-down)
|
||
- [ ] Inspect prong sockets on bracket (no strands, smooth)
|
||
- [ ] Ream or smooth M3 thumbscrew bore in base clamp
|
||
- [ ] Test T-nut pocket (slides in/out of rail groove smoothly)
|
||
- [ ] Assemble: M3 thumbscrew + washer
|
||
- [ ] Assemble: M5 × 25 bolt + 2 washers + lock nut
|
||
- [ ] Mount bracket on hinge pin (hand-tight fit)
|
||
- [ ] Insert one M5 × 8 index pin at 0° (test fit)
|
||
- [ ] Mount GoPro camera (prongs snap in)
|
||
- [ ] Final check: camera level in 0° position
|
||
- [ ] Stow extra index pins in camera bag
|