Hardware Design Fundamentals

Hardware Design Fundamentals: A Comprehensive Guide

Hardware design engineers create application specific embedded hardware solutions. Assistance systems, sensors, HMI, motion control, IOT, logistics, data visualization, safety controls, protocols, and interoperable networked technology live in every industry. Creating an electronic brain, merging it with a protective and functional product enclosure, and then connecting those hardware design specifications with your product goals yields technology that can grow out of prototyping to mass production. 

Hardware Scoping

A keen electrical engineer scopes the high-level demands of the product. They ask questions about the goals and priorities of the hardware product, then sketch the initial expectations of the hardware output. They collaborate with the mechanical engineering team to design cohesive solution that adds the most value.

  • Power-What kind of demands for power, and how best to plan to get that power to the circuitry.
  • Number of Functions- The ways the product will be used, and the actions the hardware needs to commit to accommodate daily use.
  • Size of the Board- Narrowing down the printed circuit board size can impact component selection, mass production potential, and routing challenges.
  • HMI- Figuring out whether the hardware will rely on simple I/O light signaling, a more complex Human Machine Interface (HMI), or other ways to operate the product.
  • Work Environment- Anticipating hardware design choices based on exposure to moisture, temperature, impact, chemicals, wear, and other environmental factors.
  • Performance- Plotting the needs of the hardware, whether it manages manual tasks, interoperable networking with other technology, complex data gathering, or other custom functions.
  • Longevity- Evaluating the long-term goals of the hardware product and opportunities to allow updates, part substitutions, and upgrades.
  • Communications/Protocols- Which protocols work best for the application, and how the communications work.
  • I/O- Whether to lean into more cost effective analog signaling or more efficient digital signaling.

Once the targets for use are outlined the hardware designer starts narrowing down the design specifics. 

Schematics Design

The hardware designer creates a pictorial representation of the future printed circuit board (PCB) prototype with a written schematic. Schematics act like a blueprint for the connections, circuitry, and parts.

  • Documentation- Clear titling, date recording, revision number, and other identifiers appear on the schematic for the convenience of client and engineer. This section may also include revision notes and areas for comment. Traceability for the design journal is kept through a shared online folder.
  • 2-D Diagram- Wiring and connections are sketched starting with a hierarchical sheet describing the general path between plug and protection, output, controller, power, connectors. Branches, nodes, pins, and consistent passive parts are noted and consistently attached. These lines portray the connections more than they represent the final length and shape of the placement in the final board.
  • Design Review- The schematic gets a formal review for power consumption and regulation, cost effective design, signal integrity, component orientation, elegant connections, Electrostatic Discharge Protection and other potential risk mitigation steps.
  • Bill of Materials(BOM)- The outline progresses to realistic part numbers for microprocessors, connectors, power modules, sensors, transistors, chips, pins, programmable devices, resistors, capacitors, and other parts. These are noted on the schematic and sourced by suppliers. The parts go through an evaluation to make sure the parts are not at risk of obsolescence and working alternative substitutions are noted.

PCB Layout and Routing

Using the schematic as a guide, the circuit board for the hardware is plotted and tested virtually. This sets the stage for prototyping.

  • Final BOM- The engineering team finalizes the bill of materials. They make their selections based on a best-case choice for quality, cost, availability, and longevity. Distinctions are made and marked for parts with substitutions and parts with no substitutions.
  • 3D Virtual Printed Circuit Board- The electrical engineer builds an accurate representation of the physical PCB in a digital environment. Accurate representations of part placement, part size, grounds, pins, signal tracks, wiring, locations on the different layers of the board, connections, and spacing are all portrayed. 
  • Refined Design- With the BOM and virtual PCB in place, the electrical engineer refines the design for power strength, circuitry footprint, better board spacing, pin to pad geometry, soldering apertures, electromagnetic interference (EMI) mitigation, electromagnetic compatibility (EMC), frequency strength, signal integrity, and heat dissipation.
  • Design Rule Check- The 3D model receives a full evaluation of minimum standards for board quality. These checks look for general anomalies (i.e., short circuits or unconnected pins) and manufacturing specific tolerances (i.e., managing current return for the task). These checks review the PCB for feasibility and Minimum Viable Product (MVP) standards before moving to physical prototype. Test points are added and recorded to improve testing in the prototype phase.

PCB Assembly and Prototyping

Once the PCB Layout and Routing are finalized and approved, the engineering team moves on to prototyping.

  • Fabrication- The virtual PCB model transitions into a physical prototype. Components are placed on a physical board from the BOM. Physical anomalies are mitigated and a last check on part substitutions is made.
  • Testing- Tests are run and rerun on the physical board. Power is supplied and the proposed limits, resistances, signal integrity, performance, and MVP standards established in the early stages match the output of the finished design. Environmental checks are added to the range of tests (i.e., Does the PCB resist signal interference from the work environment?). 

Enclosure Design

Working alongside the PCB layout and prototyping stages, cross-collaboration between the electrical engineering team and the mechanical engineering team creates a custom enclosure for the hardware product. With similar levels of product development, the enclosure allows regular use of the delicate components in the hardware.

  • Protection- The enclosure fits, protects, and limits access to your hardware. The strength of the enclosure matches the Ingress Protection Rating (IP Rating) for exposure to moisture, temperature, impact, chemicals, weather, wear, and other exposures caused by practical use of the hardware product. Engineers also consider safe handling for users and ways the enclosure can limit tampering.
  • Application Specific- The designers anticipate challenges, regulations, and nuances unique to the industry discipline of the hardware. When a customer seeks a hardware solution for Aerospace, Automotive, Consumer Electronics, Rugged Industry, Transportation, Logistics, Security, Surveillance, Medical, or any other specialty, they can confirm the hardware fits the norms of the discipline.
  • Aesthetics- Shape, texture, color, and branding elements are not afterthoughts in hardware design. When you receive your product, it should portray your company’s distinctive identity, capture the attention of users, and communicate the originality of your hardware.
  • Interface- The engineering team considers user interaction, button placement, port accessibility, and ergonomics to create intuitive hardware products. They mitigate fatigue  and engineer comfort into the user experience.
  • Cost Effectiveness- Designs, materials, and enclosure parts need to match quality with practical solutions that support potential mass production. The engineering team seeks assembly processes and materials that work within the margins of the budget while seeking maximum quality.

High volume PCB assembly

With the internal hardware and enclosure assembled, final tests are run on the completed hardware product to confirm it meets the MVP standards set out in the beginning of the project. Once confirmed, it is up to the client to decide how far the manufacturing goes. A hardware project can end with a single prototype or a small batch, but the ideal hardware design engineering team plans for mass production.

  • Modular Design- An ideal hardware engineering team plots for future updates, allows for easy substitutions, and keeps a deep library of scalable designs to cut costs and allow swift delivery. They work with a compatible architecture of parts, boards, and assets that can quickly turnaround upgraded designs and secondary additions to your success. 
  • Single Source- Keeping design and mass production under the same roof grants you maximum intellectual property protection and institutional memory. You stay connected with the same team that realized your hardware product in the first place. Amercian made high volume PCB assembly should only be single source.  
  • PCB Assembly Line- The key to hardware mass production revolves around mass production of printed circuit board assembly. An effective hardware engineering line automates the solder paste stenciling, component pick and place, through hole insertion, reflow heating, quality assurance, inspection, and testing. Swift repeatable assembly supports consistent cost effective construction of your hardware products on a large scale.
  • Box Build- Otherwise known as complete assembly, a fully automated hardware assembly engineering system combines the stages of PCBA, enclosure manufacturing, cabling, subassembly, and all electromechanical components in the final construction of the product and automates the construction of the final hardware product. The product moves to automated testing for everything from weight and dimensional consistency to retests of things like signal integrity and power. The Box Build stage can even extend to automated packaging and palletizing.

Let us partner with you on your Hardware Design. Tell us more about your project, schedule a virtual meeting, or call (262)-622-6104 to learn how DEVELOP LLC can mass produce your hardware solution.