week15. System integration

Assignment

Individual assignment

• Design and document the system integration for your final project

Individual Assignment

For this week’s assignment, I worked on integrating the PCB and 3D-printed enclosure for my final project. This process included the following steps:

1. PCB Design

To enable system integration, I designed a custom PCB using Fusion 360 tailored to the final project.
The board includes headers for connecting sensors, power input, and communication pins.

Design Process

1. Circuit Schematic Design
   I first created a circuit schematic in Fusion 360 and placed key components such as:

• ESP32-C3 microcontroller
• 24GHz motion detection / Doppler radar sensor module
• Transistors
• Resistors and capacitors
• Pin headers for external motor connection

2. PCB Layout
   After completing the schematic, I moved on to the PCB layout.

• I routed the traces carefully to avoid interference.
• I added mounting holes to match the design of the enclosure.

3. Exporting PNG Files
   To fabricate the PCB using a CNC milling machine, I exported the following files:

• traces.png: for milling copper traces
• millholes.png: for drilling component holes
• outline.png: for cutting the board outline

TIP

• All traces were verified using Design Rule Check (DRC).

2. Enclosure Design

I modified the 3D model created in week02 to accommodate the PCB.

3. Integration of PCB and Internal frame

• Import the 3D model of the PCB into the Fusion 360 enclosure design and align it for a perfect fit to the internal frame.
• Adjusted mounting holes and support structures based on the PCB dimensions and connector positions.

4. PCB Fabrication and Assembly

Based on the PCB data designed in Fusion 360, I physically fabricated the board using a CNC milling machine.

PCB Milling

• Equipment used: CNC router (e.g., Genmitsu PROVerXL 4030)
• Bits used: 0.1mm V-bit (for traces), 0.7mm end mill (for holes and outline)
• Fabrication steps:
  1. Milled copper traces using traces.png
  2. Drilled component holes using millholes.png
  3. Cut the PCB outline using outline.png

• Mounted components:

  • ESP32-C3 microcontroller
  • 24GHz radar sensor (NJR4265RJ1C1)
  • Resistors and capacitors (SMD and through-hole)
  • Transistors
  • Pin headers (for motor control)

• Soldering method:

  • Through-hole components were soldered manually

  • SMD components were soldered using tweezers and a temperature-controlled soldering iron

  • Insulation tape was applied to the bottom of the ESP32-C3 module before mounting to prevent the underside pads from contacting other conductive surfaces

    

• Inspection:

  • Performed continuity checks and confirmed power voltage
    

Final Assembly Photos

5. 3D Printing of Enclosure and Internal Frame & PCB Integration

After completing the PCB, I printed the designed enclosure and internal frame using a 3D printer, and integrated the PCB.

3D Printing

• Printer used: Bambu Lab P1S
• Filament: PLA (white/green), nozzle diameter: 0.4mm
• Print settings:
  • Layer height: 0.2mm
  • Infill: 15%
  • Supports: auto-generated where needed

Integration Process

• Secured the PCB to the internal frame using screws and confirmed the positions of pin headers and sensors
• Inserted the frame into the enclosure and checked for fit and clearance
• Finalized alignment of external connectors and power input before closing the enclosure

6. Sticker Creation and Decoration

To add character to the enclosure's appearance, I used the Silhouette Curio 2 to create and apply a sticker of Golgo 13's iconic eyebrows.

Sticker Creation Steps

• Design preparation: Prepare an image of Golgo 13’s eyebrows

• Editing in Silhouette Studio:

  1. Launch Silhouette Studio and import the image
  2. Use the tracing tool to convert the image into a path ([Trace Area] → [High Threshold Trace])
  3. Remove unwanted borders and noise, keeping only the eyebrow path
  4. Adjust the size and orientation as needed
     

• Cutting Setup:

  • Equipment: Silhouette Curio 2
  • Material: Black vinyl sheet
  • Settings: Adjust cutting pressure, blade depth, and speed based on test cuts

• Cutting Execution: Accurately cut the eyebrows from the vinyl and weed out unnecessary areas
  

• Transfer and Application:

  • Use transfer tape to position the sticker carefully on the front of the enclosure
  • Remove air bubbles, press firmly, and peel off the transfer tape
    

Result

• Adding the sticker emphasized the unique identity of the Golgo 13 Machine
• It enhanced the visual impact and made it a standout feature for presentations and exhibitions

Evidence of System Integration

• The PCB is properly positioned and securely mounted inside the custom-designed enclosure.

3D file Download
PCB file Download
Sticker file Download

Reflection

This integration step was crucial in transforming the electronics and mechanical design into a cohesive, functional system.
I was able to validate dimensions, refine the layout, and ensure that the design both looked and functioned like a finished product.

Related Links

• My Final Project Page