Breaking the Box: How We Designed a Non-Rectangular SBC

In embedded hardware design, single-board computers (SBCs) are typically rectangular. This shape simplifies manufacturing, assembly, and electromagnetic compatibility (EMC) layout. However, real-world projects often present structural space constraints and interface distribution requirements that compel us to adopt irregular SBC shapes to accommodate the final product’s industrial design.

This article shares our recent experience designing a custom Android/Linux SBC, addressing housing structural limitations and interface layout conflicts, ultimately leading to an irregularly shaped solution.

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🧩 Project Background

Client Requirements:

• The final product is an embedded smart terminal installed within a non-standard plastic enclosure.

• Components like the screen, buttons, camera, speaker, microphone, USB, serial port, and network port must be exposed from different orientations.

• The internal space of the housing is extremely tight, making it impossible for a traditional rectangular PCB to accommodate all interfaces.

Challenge: Fragmented space and highly restricted interface directions prevent the use of conventional SBC shapes.

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🛠️ Design Considerations

After evaluating multiple solutions, we determined the following principles:

• Interface Priority Distribution: Layout PCB based on the position of interfaces in the housing.

• Centralized Power and Main Control: Concentrate SoC, power management chips, and memory in a core area for better heat dissipation and shielding.

• Avoid Multiple Sub-Boards: To control costs and reduce failure rates associated with excessive FPC connections.

• Puzzle-Like Irregular Shape: Trim the SBC according to the housing contour to fit snugly within the housing.

The final SBC adopts a “T-shaped” structure, with one side housing the main control and memory core area, and the other sides extending modules like USB, audio, and GPIO.

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🧱 Layout and PCB Design Techniques

• Multi-Zone Power Distribution: Separate power lines for different modules to ensure power integrity.

• EMC Handling for Extended Interfaces: Add ground layers and TVS protection to extended interface areas.

• Precise Edge Processing: Mechanical drawings precisely match the plastic housing mold data.

• 3D Modeling for Synchronized Design: Use SolidWorks and Altium for interactive collaboration.

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🧪 Assembly Verification and Prototyping

In the first prototype, we used 3D-printed housing and PCB models for trial assembly, avoiding multiple mold revisions. After soldering all modules, the entire board was installed without stress points, and all interface directions were correct, passing client testing.

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✅ Summary

Although irregularly shaped SBCs increase design complexity, in scenarios with limited space and dispersed interfaces, such designs can:

• Meet product industrial design requirements.

• Improve interface integration and layout flexibility.

• Avoid instability caused by FPC connections in split solutions.

In the future, as more customized smart devices emerge, irregular SBCs may become commonplace. Engineers need to consider structure, heat, signals, and processes comprehensively to ensure system stability.

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If you’re developing a customized SBC, feel free to contact us to discuss more design experiences and case studies!

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