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Assembly Guide

Physical assembly and mounting instructions for your SpoolBuddy station.


Tools Required

  • Phillips screwdriver (small)
  • Soldering iron + solder
  • Wire strippers
  • Double-sided tape or mounting adhesive
  • 3D printer (for enclosure)

Assembly Overview

┌─────────────────────────────────────────────────────────────┐
│                   SpoolBuddy Station                        │
│                                                             │
│   ┌─────────────────────────────────────────────────────┐   │
│   │             CrowPanel 7.0" Display                  │   │
│   │               (Mounted Upright)                     │   │
│   └─────────────────────────────────────────────────────┘   │
│                          │                                   │
│   ┌──────────────────────┴──────────────────────────────┐   │
│   │    ┌────────────────────────────────────────┐       │   │
│   │    │          Scale Platform               │       │   │
│   │    │    ┌──────────────────────────────┐   │       │   │
│   │    │    │      Spool Placement         │   │       │   │
│   │    │    │    ╭──────────╮              │   │       │   │
│   │    │    │    │  NFC     │  ← Antenna   │   │       │   │
│   │    │    │    │  Reader  │    Below     │   │       │   │
│   │    │    │    ╰──────────╯              │   │       │   │
│   │    │    └──────────────────────────────┘   │       │   │
│   │    └────────────────────────────────────────┘       │   │
│   │    ┌─────────────────┴─────────────────┐            │   │
│   │    │         Load Cell (hidden)        │            │   │
│   │    └───────────────────────────────────┘            │   │
│   │    ┌──────────┐           ┌──────────────┐          │   │
│   │    │NAU7802   │           │  Pico + NFC  │          │   │
│   │    └──────────┘           └──────────────┘          │   │
│   └──────────────────────────────────────────────────────┘   │
└─────────────────────────────────────────────────────────────┘

Step 1: Mount the Load Cell

The 5kg load cell is a bar-type single-point sensor. One end is fixed to the base, the other supports the scale platform.

                 Fixed End                    Free End
                    │                            │
                    ▼                            ▼
            ┌───────────────────────────────────────────┐
            │  ●                                    ●   │
            │     ┌─────────────────────────────┐       │
            │     │    Strain Gauge Element     │       │
            │     └─────────────────────────────┘       │
            │  ●                                    ●   │
            └───────────────────────────────────────────┘
                 │                                │
            ┌────┴────┐                    ┌──────┴──────┐
            │  Base   │                    │   Platform  │
            │ (fixed) │                    │  (floats)   │
            └─────────┘                    └─────────────┘

Mounting Steps

  1. Attach to base - Use 2x M4x25 screws on the fixed end. Ensure load cell is level. Tighten firmly.

  2. Attach platform - Use 2x M4x25 screws on the free end. Platform should "float" and only connect via load cell.

  3. Check clearance - Platform should not touch base or sides. Maintain ~2-3mm gap all around.

Critical

The load cell must be the ONLY connection between base and platform for accurate readings.


Step 2: 3D Printed Enclosure

A complete 3D printable enclosure kit is available on MakerWorld:

Download Enclosure from MakerWorld

The enclosure includes:

  • Base plate with load cell mounting points
  • Scale platform (connects to load cell)
  • Electronics bay for NAU7802 and Raspberry Pi Pico
  • PN5180 NFC antenna mount
  • Display frame for CrowPanel 7.0"
Setting Value
Material PETG
Infill 15%
Walls 3
Supports None

Final Checklist

Mechanical

  • Enclosure printed and assembled
  • Load cell securely mounted
  • Platform attached to load cell (free-floating)
  • Platform has clearance (doesn't touch sides)
  • Display mounted stably

Electrical

  • All wiring complete per Wiring Guide
  • No loose connections
  • Wire routing away from moving parts
  • Power cables accessible

Verification

  • Platform moves freely when pressed
  • No binding or rubbing
  • All components secured

Next: Firmware Installation