Designing a printed circuit board (PCB) from scratch is one of the most rewarding steps in learning embedded systems and hardware engineering. In this project, I developed an STM32-based PCB design using KiCad (version 9), taking the idea from schematic design all the way to preparing files for manufacturing and assembly.

This post documents the full journey — from selecting the right components, to schematic capture, PCB layout, routing, and final preparation for fabrication. Unlike prebuilt Arduino boards, this project gave me complete control over the design, helping me understand the real-world workflow of hardware design.



🔧 Project Overview

The goal of this project was to design a custom microcontroller development board based on the STM32F103C8T6, a widely used ARM Cortex-M3 microcontroller.

The board includes all necessary supporting circuitry for stable operation, debugging, and communication interfaces, making it a professional alternative to hobby-grade boards.



📐 Schematic Design


The first step was creating the schematic diagram in KiCad. I carefully selected each component and designed the supporting circuitry to ensure reliable performance.

Key Components Used:

  • Microcontroller: STM32F103C8T6

  • Voltage Regulator: AMS1117-3.3

  • Crystal Oscillator: 16 MHz (ECS-160-20-33B-TR)

  • Capacitors:

    • 100 nF (C0805C104K5RACTU) for decoupling

    • 10 µF (C0805C106K5RACTU)

    • 22 µF (C0805C226K5RACTU)

  • Resistors:

    • 1.5 kΩ (CR06031K50K)

    • 10 kΩ (CR060310K00K)

  • USB Connector: USB Micro-B (1012009-0001)

  • Switch: SPDT Tactile Switch (B3F-1022)

All parts were verified against the JLCPCB library, ensuring that they were available for manufacturing and assembly.



📏 PCB Layout


After completing the schematic, I moved on to the PCB layout phase. Since this was a two-layer board, I defined clear design rules based on JLCPCB’s manufacturing capabilities.

Layout Highlights:

  • Compact placement: Microcontroller and crystal kept close to minimize trace delay.

  • Ground plane: Designed a solid ground plane for noise reduction and stable operation.

  • Power routing: Wide traces used for VCC and GND paths.

The KiCad 3D Viewer was used to visualize the board before finalizing. This helped identify clearance issues and refine the layout.



🖇 Routing Strategy

Routing is a critical step in ensuring signal integrity and reliable communication. I followed best practices for sensitive signals:

  • USB Differential Pair: Routed USB_D+ and USB_D– as matched-length differential traces.

  • Debugging Interface: SWDIO and SWCLK connected to a standard debug header for programming.

  • I²C Bus: SDA and SCL routed with pull-up resistors to 3.3V.

  • Decoupling: Placed capacitors close to VCC pins of the microcontroller.

Clearance rules were applied to avoid crosstalk, and trace widths were adjusted according to current requirements.


📂 Downloads 

📂 Schematic File ,PCB Design File : Download Here


🏭 Manufacturing Preparation

Finally, the project files were prepared for JLCPCB manufacturing and assembly. By using parts from their library, I ensured compatibility and reduced risks of sourcing issues.

This experience also helped me understand how professional hardware teams transition from design → prototyping → production.



💡 Skills Gained

Through this project, I strengthened my skills in:

  • KiCad PCB Design (v9)

  • Schematic Capture & Component Selection

  • PCB Layout Optimization & 3D Visualization

  • Routing Critical Signals (USB, I²C, SWD)

  • Preparing Manufacturing Files (Gerber, BOM, Pick & Place)



✅ Project Outcome

This project gave me hands-on experience in end-to-end PCB design. Unlike simply using Arduino or ready-made modules, I now have the confidence to design custom boards tailored to specific applications.

The STM32-based board I designed can be used for embedded development, IoT applications, and learning low-level microcontroller programming.

This experience also set the foundation for tackling more complex, multi-layer designs in the future and contributing to professional hardware engineering projects.