Hardware Assembly and Mounting

This guide covers the physical assembly of the Mini Pupper v2, including mounting the camera, cooling fan, and 3D printed components.

Prerequisites

Before starting, ensure you have:

Completed Cable Preparation
Mini Pupper v2 robot (assembled base)
3D printed camera mount
3D printed fan mount
M2 and M2.5 screws
Small Phillips screwdriver

Part 1: Camera Mount Installation

Step 1: Prepare the Camera Mount

3D Printed Camera Mount:

Download from camera.zip
Print with PLA or PETG
20-30% infill recommended
Enable supports if needed

Step 2: Attach Camera to Mount

Position the camera module in the mount bracket
- Camera lens should face forward
- PCB sits in the bracket recess
Adjust camera angle
- Typical angle: 10-15° downward
- Allows robot to see ground and forward
- Test angle before securing
Secure the camera
- Use M2 screws (usually 2-4 screws)
- Don’t overtighten - plastic can crack
- Camera should be stable but not stressed

Step 3: Mount Bracket to Robot Head

Position the mount on the Mini Pupper’s head
- Align with mounting holes
- Ensure ribbon cable has clearance
Insert screws (M2 or M2.5)
- Start all screws before tightening
- Tighten in a cross pattern
- Alternate between screws for even pressure
Verify stability
- Mount should be solid with no wobble
- Camera should maintain angle
- Ribbon cable should have slack

Step 4: Test Head Movement

Important: Test before final assembly

Manually move the head through full range of motion
- Pan left and right
- Tilt up and down
- Check for cable interference
Check for issues
- Ribbon cable should move freely
- No pinching or snagging
- No tension on cable connections
Adjust cable routing if needed
- Add slack where necessary
- Secure with tape or small zip ties
- Ensure clearance from servos

Part 2: Cooling Fan Installation

Step 1: Prepare the Fan Mount

3D Printed Fan Mount:

Download from fan.zip
Print with PLA or PETG
20-30% infill recommended
Check fit before final assembly

Step 2: Install Fan in Mount

Check airflow direction
- Fan should blow air ONTO the Raspberry Pi
- Look for arrow on fan housing
- Arrow shows airflow direction
Position fan in mount
- Align screw holes
- Ensure wires exit in correct direction
Secure with screws
- Use screws included with fan (usually M3)
- Tighten evenly
- Don’t overtighten plastic

Step 3: Mount Fan Assembly to Robot

Position the fan mount on the robot body
- Should be above or near the Raspberry Pi
- Ensure airflow path is clear
- Check wire routing to GPIO pins
Attach to mounting points
- Use M2.5 or M3 screws
- Secure firmly but don’t crack plastic
Verify airflow
- No obstructions in front of fan
- Air can flow freely over Raspberry Pi
- Wires don’t block airflow

Part 3: Cable Management

Organize and Secure Cables

Goals:

Prevent snagging on moving parts
Maintain neat appearance
Allow for disassembly if needed
Ensure reliability

Techniques:

Bundle related cables
- Use small zip ties or twist ties
- Don’t overtighten - allow some movement
- Group by function (power, data, etc.)
Route along structural members
- Follow robot frame when possible
- Use existing cable channels
- Avoid crossing open spaces
Secure at stress points
- Near connectors
- At movement joints
- Where cables change direction
Leave service loops
- Extra length near moving parts
- Allows for maintenance
- Prevents tension on connectors

Cable Routing Best Practices

Camera Ribbon Cable:

Gentle curves only (no sharp bends)
2-3cm slack near head joint
Secured to prevent flopping
Away from servo mechanisms

Fan Wires:

Short, direct path to GPIO
Secured to prevent disconnection
Not blocking airflow
Protected from pinching

USB Cables (if used):

Route to accessible location
Secure to prevent pulling
Label for identification

Part 4: Final Assembly Check

Visual Inspection

Check each component:

Functional Tests

Before closing up:

Power on test
- Connect power adapter
- Verify power LED
- Check fan spins
- Wait for boot sequence

Camera test

# SSH into Mini Pupper
ssh ubuntu@<mini-pupper-ip>
   
# List cameras
libcamera-hello --list-cameras
   
# Should show: Available cameras: 1

Movement test
- Robot should stand up after boot
- Manually test head movement
- Check for cable interference
- Listen for unusual servo sounds

Temperature test

# Check CPU temperature
vcgencmd measure_temp
   
# Should be under 60°C at idle
# Fan should keep it under 70°C under load

Part 5: Troubleshooting Assembly Issues

Camera Mount Issues

Problem	Cause	Solution
Mount wobbles	Screws not tight	Tighten screws evenly
Camera angle changes	Mount flexing	Use more screws, reinforce mount
Ribbon cable pinched	Poor routing	Reroute with more slack
Mount cracked	Overtightened	Print new mount, use less force

Fan Mount Issues

Problem	Cause	Solution
Fan vibrates	Loose mounting	Tighten screws, check alignment
Fan noisy	Obstruction	Check for debris, ensure clearance
Poor cooling	Wrong airflow direction	Reverse fan orientation
Mount loose	Wrong screws	Use correct size screws

Cable Management Issues

Problem	Cause	Solution
Cables snagging	Poor routing	Reroute away from moving parts
Ribbon cable damaged	Sharp bend	Replace cable, improve routing
Wires disconnecting	No strain relief	Add zip ties near connectors
Messy appearance	No organization	Bundle and secure cables

Part 6: Maintenance Tips

Regular Checks (Monthly)

Inspect camera mount
- Check for cracks or loosening
- Verify camera angle hasn’t shifted
- Clean lens with microfiber cloth
Check fan operation
- Listen for unusual noises
- Verify fan spins freely
- Clean dust from fan blades
Inspect cables
- Look for wear or damage
- Check connections are secure
- Verify routing hasn’t shifted
Tighten screws
- Vibration can loosen screws over time
- Check all mounting screws
- Don’t overtighten

Cleaning

Camera Lens:

Use microfiber cloth only
Gentle circular motion
Don’t use liquids unless necessary
Compressed air for dust

Fan:

Power off first
Use compressed air
Don’t spin fan manually
Check for obstructions

Cables:

Wipe with dry cloth
Check for fraying
Don’t pull or tug
Replace if damaged

Part 7: Upgrades and Modifications

Optional Enhancements

Better Camera Mount:

Design with adjustable angle
Add vibration dampening
Include cable management clips

Improved Cooling:

Add heatsinks to Raspberry Pi
Use larger fan (40mm)
Add temperature-controlled fan speed

Cable Management:

3D print cable clips
Use spiral cable wrap
Add cable channels to body

Protection:

Add camera lens protector
Use dust covers
Protect exposed connectors

Safety Notes

During Assembly:

Work on stable, flat surface
Keep small parts organized
Don’t force components
Use correct size screwdriver

Electrical Safety:

Power off before working on robot
Don’t touch GPIO pins while powered
Verify connections before powering on
Keep liquids away from electronics

Mechanical Safety:

Watch for pinch points
Keep fingers clear of servos
Don’t overtighten screws on plastic
Wear safety glasses when using compressed air

Next Steps

After completing hardware assembly:

Setup Mini Pupper - Configure software and WiFi
Jupyter Setup - Access the web interface
Test Camera - Verify camera functionality
Test Sensors - Check all hardware