# Bill of Materials – 3D Printed Fuse Box
## 🔩 Hardware & Fasteners
- **24 × M3 threaded inserts** (5×5 mm)
- **18 × M3 bolts** (10 mm length)
- **4 × M3 bolts** (16 mm length, for securing the lid)
## ⚡ Electrical Components
- **2 × 12V 4-channel relay modules**
- **8 × Automotive blade fuses** (rating depends on load requirements)
- **Up to 9 × Aviation connectors**
- At least **1 × 8-pin connector**
- Remaining connectors as required by configuration
- **16 × Brass female spade connectors** (non-insulated, 6.3 mm)
- **1 × 12V DC power jack (male socket)**
## 🧠 Control & Logic
- **1 × Arduino Uno R4**
- **1 × Arduino Uno R4 I/O Expansion Shield**
- (This is the **screw terminal shield**, often called a *terminal block shield* or *sensor shield*, used for easy wire connections to the Arduino.)
## 🧵 Wiring
- **Dupont jumper wires** (for 5V signal connections)
- **Appropriate gauge wire** (for higher-current 12V connections)
## 🖨️ 3D Printed Parts
- **1 × 12V Fuse Wire Connector (8-slot)**
- [MakerWorld model link](https://makerworld.com/en/models/1904128-12v-fuse-wire-connector#profileId-2041169)
- Designed for standard automotive blade fuses and 6.3 mm spade terminals
### Notes
- The **fuse ratings** should be selected based on the load of each circuit.
- The **aviation connectors** allow modularity—choose pin counts based on your wiring needs.
- The **I/O expansion shield** simplifies wiring by providing screw terminals or headers, reducing the need for soldering directly to the Arduino.