At its core, a single-board computer (SBC) is exactly what it sounds like: a fully functional computer built on a single printed circuit board (PCB). Instead of requiring separate motherboards, RAM sticks, and storage drives, an SBC integrates the processor, memory, storage, power management, and common communication interfaces into one cohesive unit.
Popular examples include the Raspberry Pi or BeagleBone, as well as AI-focused powerhouses like the NVIDIA Jetson, or System-on-Modules (SOMs) from manufacturers like Toradex and Variscite.
When evaluating these options, it is important to distinguish between hobbyist boards and industrial-grade modules. While a standard Raspberry Pi is excellent for rapid prototyping and maker projects, industrial SBCs and SOMs are engineered for more specific applications. Industrial variants are designed to withstand harsh environments, extreme temperatures, and continuous vibration, and they often come with long-term supply guarantees.
Regardless of the SBC that is ultimately chosen, the core module rarely stands alone in a final commercial product. Off-the-shelf boards have generic outputs, which usually necessitates a custom carrier board. A carrier board hosts the SBC and connects it to application specific hardware components, such as specialized sensors, power supplies, displays, or motor controllers.
The Advantages of Using a COTS SBC
Choosing a commercial off-the-shelf (COTS) single-board computer offers several strategic benefits, particularly in the early stages of a product’s lifecycle:
- Faster Development: COTS SBCs arrive ready to boot. With an operating system like Linux already running and device drivers readily available out of the box, engineering teams can begin software development immediately rather than waiting weeks or months for custom hardware to be fabricated.
- Lower Upfront Engineering Cost: The most expensive and time-consuming aspects of hardware engineering are bypassed completely. There is no need for complex processor PCB design, high-speed DDR memory routing, or intricate power sequencing. Instead, the hardware effort is reduced to designing a simpler carrier card to handle extra peripherals, such as motor drivers, USB/network hubs, battery charging circuits, or specialized data acquisition components. Crucially, this allows engineers to fully validate software and core functionality before committing significant capital to a fully custom processor board.
- Excellent for Proof-of-Concepts: SBCs excel in rapid prototyping by eliminating early hardware bottlenecks. Functional demonstrations can be assembled quickly, easily supporting investor presentations, internal milestones, and early customer evaluations.
- Reduced Technical Risk: COTS boards are proven, mass-produced hardware. This makes hardware debugging significantly easier and reduces the chance of expensive board revisions. Additionally, there is often an extensive software ecosystem developed for the board, providing community support and pre-existing libraries to accelerate development.
When a COTS SBC Is the Right Choice
Given the advantages of development speed and reduced engineering risk, COTS single-board computers shine in scenarios where rapid deployment is paramount. They are an ideal foundation for proof-of-concept projects and Minimum Viable Products (MVPs). An SBC can produce functional prototypes in a fraction of the time required for custom hardware.
Beyond early-stage prototyping, SBCs are the perfect fit for very low production volumes. In these scenarios, the high upfront Non-Recurring Engineering (NRE) costs of designing a custom processor board are unnecessary. They are also a strategic choice for products where time-to-market matters more than the per-unit Bill of Materials (BOM) cost. If beating a competitor to launch is the absolute highest priority, accepting a slightly more expensive off-the-shelf module can be an effective trade-off.
These off-the-shelf boards are equally valuable for building internal tools, specialized research equipment, and automation prototypes. In these use cases, immediate functionality and reliability take precedence over aggressive miniaturization or cost optimization. Even in applications that do not fully utilize the impressive processing power of a modern SBC, having a stable, working system immediately usually outweighs the inefficiency of any unused processing headroom.
If the goal is getting software running next month rather than shipping 10,000 units next year, a COTS SBC is often the right decision.
The Limitations of Commercial SBCs
While single-board computers offer an incredible head start, there is a reason many successful products eventually outgrow them. COTS SBCs are designed as general-purpose hardware intended to serve as many applications as possible, making them inherently optimized for none. As a product matures, scales in production, or requires specialized form factors, the very features that made the SBC appealing during prototyping can become significant liabilities.
One of the most immediate drawbacks is a higher per-unit cost at volume. When purchasing an off-the-shelf board, the cost inevitably includes hardware that may not be needed in a specific application. Some products may only require a basic processor and a few sensor inputs, but purchasing an SBC includes paying for features of the board that won’t be used, such as HDMI ports, USB hubs, Ethernet controllers, audio jacks, extra connectors, and surplus memory/storage. Beyond just the financial cost, these unused interfaces can hinder performance. Application critical interfaces may be forced to share internal buses with unused components, creating unnecessary bottlenecks.
This one-size-fits-all approach also dictates a larger physical footprint. When developing a compact, highly integrated device, squeezing a generic rectangular board into a custom enclosure can be incredibly frustrating. Tall connectors and rigid mechanical constraints often force product designers to make unwanted compromises to the final product’s shape and aesthetics.
Availability and product lifecycle present another major hurdle. Consumer-grade boards can suddenly disappear from the market, undergo unannounced revision changes, or suffer from exceptionally long lead times. Industrial products demand a predictable supply chain that many COTS boards simply cannot provide.
Finally, it is important to remember that opting for an SBC does not entirely eliminate hardware engineering. Most real-world applications cannot rely on the SBC alone; they usually require a custom printed circuit board in the form of a carrier card to add application-specific functionality. While developing this carrier card is certainly cheaper and faster than engineering a full custom processor board from scratch, it is still a mandatory development effort that must be factored into the project timeline and budget.
When a Custom Processor PCB Makes Sense
As a product matures or targets a more demanding market, transitioning away from an off-the-shelf module to a custom processor PCB often becomes the natural path. This fully custom approach makes the most financial sense when moving into medium to high production volumes. At scale, the upfront engineering costs of designing a custom board are quickly offset by the savings of stripping away unused connectors, extra memory, and unnecessary silicon. However, some COTS SBCs, such as the Raspberry Pi, use proprietary CPUs that cannot be used on custom PCBs. This results in significant development effort to port the application software to a new operating environment. Due to this, it is recommended to only use commercial boards that have publicly available CPUs, making the transition from a COTS board to a custom board seamless.
Beyond volume economics, a custom design is frequently the only viable solution for products with strict physical constraints. Custom PCBs can be designed to fit highly compact or unusually shaped enclosures. It also allows for strict thermal management strategies to be implemented that are tailored to the final system mechanical design.
Custom hardware is also a critical requirement for specialized, high-performance applications. Systems requiring high-speed data acquisition rely on heavily optimized signal routing that general-purpose boards may not incorporate. Furthermore, highly regulated or demanding fields, such as medical devices, aerospace, and heavy industrial equipment, demand a level of reliability, environmental tolerance, and rigorous component traceability that can only be achieved when designing the system from the ground up. Lastly, if a product has a long-expected lifecycle, designing a custom PCB provides complete control over component supply chain, protecting the product from unexpected obsolescence for years to come.
The Advantages of a Custom Embedded Processor Board
Designing a custom embedded processor board allows designers to tailor the hardware specifically for a product’s unique requirements. This granular control addresses all of the shortcomings of COTS SBCs:
- Lower Production Costs: At higher production volumes, a custom board yields a significantly lower per-unit Bill of Materials (BOM) cost by including only the minimum required components for the application.
- Optimized Performance: By integrating only the peripherals that are needed for the application, signal routing and power distribution can be made much more efficient. When a PCB is designed for a specific application, all aspects of the board can be designed for maximum efficiency, including high-speed interfaces, memory configurations, power consumption, and thermal performance.
- Unique Physical Design: A custom board can be seamlessly engineered to fit the mechanical requirements of the system. This results in a smaller form factor, a lower profile, and substantially easier mechanical integration.
- Superior Supply Chain Control: A custom design provides unmatched control over a product’s lifecycle and availability. By deliberately selecting processors with guaranteed long-term lifecycle support from trusted industrial-grade suppliers, a robust supply chain management plan can be made. This protects the manufacturing pipeline and mitigates availability issues with critical components.
Choosing the Right Approach
Deciding between an off-the-shelf module and a fully custom design ultimately comes down to balancing immediate development priorities against long-term production goals.
A COTS SBC should be used when the primary objective is speed and design validation. This is the optimal path when needing a prototype up and running quickly, or when actively validating a new concept. It is also the right choice when physical hardware requirements are flexible, anticipated production quantities are low, and getting started on software development immediately outweighs all other concerns.
On the other hand, a custom processor board should be used when wanting to ship mature production units at moderate to high quantities. At this scale, per-unit BOM cost becomes a major factor, and a custom design will protect profit margins. Custom hardware is also the necessary choice if a product has strict size constraints, demands peak performance, or is intended to be a long-term product with a robust supply chain.
Final Thoughts
Neither approach is universally superior for every application, and many products end up going down both paths. The most effective long-term hardware strategy often follows a natural three-step evolution. First, a proof-of-concept unit using a commercial SBC or SOM is built to rapidly validate software and core functionality. Next, a custom carrier board is designed to incorporate application-specific peripherals and verify real-world field performance. Lastly, a fully custom processor PCB is built for production volumes to optimize BOM cost, physical footprint, and supply chain reliability.
Whether you are currently prototyping with an SBC and need a custom carrier board to bridge the gap, or you are ready to transition your product to a complete, custom-designed embedded processor PCB, our team at MJS Designs is available to help. We support customers at every stage of the hardware lifecycle, from initial engineering to final manufacturing, to ensure your product scales successfully and gets to market on time. Contact us today to learn how our team can help you streamline development, reduce risk, and accelerate your path to market.
