# Assembly Instructions

Step-by-step guide to physically build your MARPY robot. Once assembled, continue to the [Wiring Guide](wiring.md) to connect everything electrically.

## What You'll Need

- All parts from the [Bill of Materials](bom.md)
- 3D printed parts (Download the STLs from [MakerWorld](https://makerworld.com/en/models/2655868-marpy#profileId-2936800))
- Basic tools: screwdriver, hex key (Allen wrench)

<img src="images/marpy_parts.jpeg" height="350" alt="All parts laid out"/>

## Step 1: Attach Motors to Motor Mounts

| Hardware | Qty |
|----------|-----|
| Motor mounts (3D printed) | 2 |
| M3x24 screws | 4 |
| M3 nuts | 4 |

1. Slide each DC motor into its 3D-printed motor mount bracket.
2. Secure each motor with 2 screws and nuts.

<p>
<img src="images/motor_mounts_assembly1.jpeg" height="250" alt="Motor mount parts"/>
<img src="images/motor_mounts_assembly3.jpeg" height="250" alt="Motor secured in mount"/>
<img src="images/motor_mounts_assembly2.jpeg" height="250" alt="Both motors with mounts"/>
</p>

## Step 2: Assemble the On/Off Switch

| Hardware | Qty |
|----------|-----|
| On/off switch | 1 |
| Switch mount (3D printed) | 1 |

1. Press-fit the on/off switch into the 3D-printed switch mount.

<img src="images/on_off_switch_assembly.jpeg" height="250" alt="On/off switch in mount"/>

## Step 3: Assemble the Caster Wheel

| Hardware | Qty |
|----------|-----|
| Caster wheel | 1 |
| M3x12 standoffs (female-male) | 4 |
| M3 shims | 4 |
| M3 nuts | 4 |

1. Attach the caster wheel to its mounting plate using screws and nuts.
2. Screw the standoffs into the caster plate, these will later connect to the base plate.

<p>
<img src="images/caster_wheel_aseembly1.jpeg" height="250" alt="Caster wheel assembled"/>
<img src="images/caster_wheel_aseembly2.jpeg" height="250" alt="Caster wheel with standoffs"/>
</p>

## Step 4: Assemble the Lower Chassis

<img src="images/lower_chassis_parts.jpeg" height="350" alt="Lower chassis parts laid out"/>

### Step 4.1: Mount Motors to Base Plate

| Hardware | Qty |
|----------|-----|
| M3x20 screws | 2 |
| M3x16 screws | 2 |
| M3 nuts | 2 |

1. Slide the motor mount brackets into the base plate slots from the bottom.
2. Secure each motor mount with the M3x16 screws and nuts.
3. Insert the M3x20 screws facing **upwards** through the base plate - no nuts needed, these will thread into the standoffs later.

<p>
<img src="images/motors_to_bottom_assembly1.jpeg" height="250" alt="Motor mounted to base plate"/>
<img src="images/motors_to_bottom_assembly2.jpeg" height="250" alt="Both motors mounted"/>
</p>

### Step 4.2: Attach Caster and Switch to Base Plate

| Hardware | Qty |
|----------|-----|
| M3x12 screws | 4 |

1. Screw the caster assembly and on/off switch to the base plate using the M3x12 screws.

<p>
<img src="images/lower_chassis_assembly_bottom_view.jpeg" height="250" alt="Lower chassis bottom view"/>
<img src="images/lower_chassis_assembly_upper_view.jpeg" height="250" alt="Lower chassis top view"/>
</p>

## Step 5: Mount the Electronics

| Hardware | Qty |
|----------|-----|
| L298N motor driver | 1 |
| Battery holder (2S 18650) | 1 |
| Buck converter | 1 |
| M3x8 screws | 8 |
| M3x6 flat head screws (optional) | 2 |

Mount the electronic components onto the base plate. Wiring is covered in the [Wiring Guide](wiring.md) later.

1. Mount the **L298N motor driver** and **LM2596S buck converter** to the base plate using M3x8 screws. Match the orientation shown in the photos.
2. Attach the **battery holder** using M3x6 flat head screws (glue/double-sided tape is also possible)

<p>
<img src="images/lower_chassis_electric_components.jpeg" height="250" alt="Electronics components before mounting"/>
<img src="images/lower_chassis_electric_assembled.jpeg" height="250" alt="Electronics mounted on base plate"/>
</p>

## Step 6: Attach the Wheels

| Hardware | Qty |
|----------|-----|
| TT motor wheels | 2 |

1. Press the yellow TT wheels onto the motor shafts.

<p>
<img src="images/wheels_assembly1.jpeg" height="250" alt="Wheels attached top view"/>
<img src="images/wheels_assembly2.jpeg" height="250" alt="Wheels attached side view"/>
</p>

## Step 7: Mount the ESP32 on Top Plate

| Hardware | Qty |
|----------|-----|
| Top plate (3D printed) | 1 |
| ESP32 DevKit V1 | 1 |
| Screw terminal breakout board | 1 |
| M3x8 screws | 6 |

1. Mount the screw terminal breakout board onto the top plate using M3 screws.
2. Plug the ESP32 DevKit into the breakout board. Keep the USB port accessible for flashing and debugging.

<p>
<img src="images/upper_chassis_components.jpeg" height="250" alt="Top plate components"/>
<img src="images/upper_chassis_assembled.jpeg" height="250" alt="ESP32 mounted on top plate"/>
</p>

## Step 8: Final Assembly

| Hardware | Qty |
|----------|-----|
| M3x40 standoffs | 4 |
| M3x12 screws | 4 |

1. Screw the 4 standoff posts into the base plate corners.

<p>
<img src="images/standoffs_assembly1.jpeg" height="250" alt="Standoffs and screws"/>
<img src="images/standoffs_assembly2.jpeg" height="250" alt="Standoffs installed"/>
</p>

2. Place the top deck assembly on the standoffs and secure with M3x12 screws.

<img src="images/final_preassembly.jpeg" height="350" alt="Both halves before joining"/>

<p>
<img src="images/final_assembly1.jpeg" height="250" alt="Final assembly front view"/>
<img src="images/final_assembly2.jpeg" height="250" alt="Final assembly side view"/>
</p>

## Done!

Next steps:

1. **[Wiring Guide](wiring.md)** - Connect all the electrical components
2. **[Firmware Setup](firmware-setup.md)** - Flash micro-ROS onto the ESP32
3. **[ROS2 Setup](ros2-setup.md)** - Start driving!