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16. System Integration

Design and document the system integration for your final project

System Integration

  1. This week’s goal is to carry out system integration for the final project. First, I sorted out all the electronic modules needed, and then designed the casing that can accommodate the entire electronic part. This is the overall architecture overview of my final project——FacePunch.

System_integration.jpg

  1. Here is my materials list.
Name Quantity Unit Price (USD)
PCB 1 $2.10
XIAO-ESP32-C3 1 $3.78
Game Button 3 $0.18 (each)
WS2812 RGB LED 3 $0.14 (each)
DF MP3 Module 1 $6.30
4Ω 3W Speaker 1 $0.42
Dupont-to-Spade Cable 15 $0.07 (each)
3D Printed Structure 1 $2.80
4mm Plywood Board 1 $1.40

Bill_of_Materials.jpg

System Integration - Circuit

  • PCB board design:To meet the requirements of the final project, I designed a new expansion board based on the XIAO-ESP32-C3. Pins D0, D2, and D4 are connected to the buttons, D1, D3, and D5 are connected to the WS2812 RGB lights. Pins D6 and D7 are connected to RX and TX respectively, and a power interface is designed for each module.
    final_schematic.jpg
    final_pcb_1.jpg
    final_pcb_2.jpg

  • I soldered a female header for the MP3 module, replacing the use of wires. This allows it to be placed close to the microcontroller, saving a significant amount of space and making the wiring neater.
    MP3.jpg

  • I’m extremely lucky. We View Adafruit website that showed this trick of including a neopixel inside the button ,My supervisor helped me find gaming buttons that can perfectly combine RGB lights and button functions. All I need to do is solder three pins for the lights.
    RGB_BUTTON.jpg

System Integration —— Structure

  • During the structural design process, I took the following points into consideration:
  • The size and shape of components (microcontroller, buttons, speaker).
  • The method of fixing components inside the housing.

  • Access to components for setup and maintenance.

  • I think the most challenging part of product structural design is how to reasonably combine the laser-cut top cover and the 3D-printed bottom structure. In the first version of the design, I used two layers of wooden boards for the top, hoping to fit them into the 3D bottom structure. However, this structure requires glue to bond the two layers of wooden boards, which may not be the best choice. 3D_structure_2.jpg
    3D_structure_01_

  • This is the second version. The wooden board（Just one layer of wooden board is enough） is completely embedded in the 3D-printed box, so that the cutting burn marks around the wooden board are not visible. This was a suggestion given to me by my supervisor, and I also think it’s a great idea.
    3D_structure.png

  • To ensure that the sound of the speaker is not blocked, I designed some holes in the structure. By using the free plugin Voronoi Sketch Generator in Fusion 360, this effect can be achieved quickly.
    Structure_fusion.jpg

  • I also designed a border for the PCB at the bottom of the 3D printed structure to prevent it from moving.
    bottom_fusion.jpg

  • There is a trick you need to know. On the PCB design website, you can export the DXF file of the PCB board structure. Then insert the DXF file into Fusion, and you can quickly view the dimensions and the positions of the holes. It’s advisable to delete the unnecessary lines in advance. Otherwise, it will definitely make Fusion 360 run very slowly. PCB_dxf.jpg

  • Finally, leaving a hole for the charging data cable is also very important. structure_hole.jpg