Electronics Hardware Prototyping Basics: Building and Testing Prototypes

3 weeks ago by Sam Holland

Early efforts at launching new electronic hardware products were long and complicated. However, with recent advances in microcontrollers and manufacturing techniques, such as 3D printing and injection moulding, engineers and designers can now take products to market faster than ever.

Developing a prototype is a critical aspect of electronics hardware design, and one whose phases need to be followed closely, step by step. Accordingly, the following defines what a prototype is, before going on to discuss the stages involved in developing one.

 

What is a Prototype?

A prototype is a preliminary model of a product from which newer models are developed. For electronic products, a prototype is the first version that is introduced to a small number of people for testing. Note, however, that prototypes may or may not be designed with the same materials, nor on the same scale, as the final products. 

 

Some Benefits of Developing Electronic Hardware Prototypes

Time and resources are some of the most essential metrics in industrial production. Below are some of the key benefits of prototyping to the overall production process:

  • The early detection and mitigation of design errors and product defects

  • The provision of continuous, real-time feedback in the interest of optimising product design

  • General assistance in determining the machinery requirements for production

  • The procurement of a proof of concept to obtain funding from investors and other project stakeholders

  • Minimisation of resource wastage,s particularly by determining material and labour requirements for full-scale production

 

Electronic prototype hooked up on a work table.

A circuit board hooked up on a work table. Image Credit: Pixabay.

 

Electronic hardware prototypes can also be of several types. These include:

Proof of Concept Prototypes

A proof of concept prototype demonstrates to all parties involved in a project that a new product design will work as intended. Before human and capital resources are committed, designers and electrical engineers will usually demonstrate a working model (on a pilot scale) to project managers and investors. This is to show that the target product is both technically and economically viable.

While a proof of concept prototype usually lacks the full functionality of a final product, it facilitates the changes that will need to be made before large-scale manufacturing is underway. And again, this leads to a reduction in production costs. 

 

Functional Prototypes

Unlike proof of concept prototypes, functional prototypes have the same appearance—and contain all the features and capabilities of—the final products (although they may be built with cheaper materials).

To further reduce production costs before they reach the end users, moreover, functional prototypes are produced on a small scale. Then, only after the prototypes have been tested extensively, will the project stakeholders decide whether to pursue full-scale production or otherwise.

 

Virtual Prototypes

As the name suggests, virtual prototypes show the finished product in a visual form. Engineers may use computer-aided design/manufacturing (aka CAD/CAM) tools, circuit modelling or 3D modelling software to design, simulate, and of course test the system-level design of a product. The prototype is then revealed to project stakeholders and manufacturers, alongside further product designers who may suggest ways to improve the design.

 

What Are the Steps of Electronic Hardware Prototyping?

 

Below are some essential steps involved in electronics hardware prototyping:

Schematic Design

The first stage of building a prototype is in creating the schematic circuit diagram. The schematic is a system-level representation of the product that shows how the components will be interconnected in the final product. Schematics can be created using electronics design software such as PCB Web or KiCad EDA. After the design is finished, it is taken to a manufacturer to produce the bare PCB into which the vital components will be integrated. (Note: while producing such a board in-house may be viable for large companies, it is often expensive for startups, engineers, and hobbyists.)

 

Component Placement and Routing

After obtaining the bare PCB, the next step is to determine the precise location of every component on the board. Component placement is a technical and highly-sensitive process that must satisfy both electrical and physical dimension rules. Using PCB design software for component placement saves time, minimises design errors, and prevents costly production runs of defective products.

It’s immediately following such placement that engineers need to create a layout with conductive tracings. These are used to link the various circuit components (resistors, capacitors, MOSFETs, etc.) that are embedded in the board.  

 

Testing and Verification

Having by now correctly placed and routed the circuit components, engineers are left to verify the final design against the original schematic for congruency. PCB design software can test for physical dimensions (e.g., wire widths, spacings between conductive tracings, etc.), as well as electrical design rules (e.g., creepage and clearance). Additionally, engineers may perform quality checks, such as those needed to ensure that signal and power traces are kept separate, there is adequate grounding, and so on).

 

Engineer testing computer.

An engineer (Intel's Russ Brown) tests a laptop for functionality. Image Credit: Wikimedia Commons.

 

Debugging

Debugging is a quality assurance (or QA) technique for finding and eliminating errors or defects in the prototype that the PCB manufacturer may have missed during the hardware part production.

 

Programming

This stage involves programming a microcontroller, which is integrated into the board to add functionality and control to the product. Typically, this is achieved using a low-level language, such as C.

 

Industrial Design

During the final stage of production, the finished electronics are built into a suitable enclosure, such as one made of metal or thermoplastic. Modern products use advanced manufacturing techniques such as 3D printing (for low-volume production) or injection moulding (for high-volume production). Electrical engineers will partner with industrial or materials engineers for this phase of the project.

 

Are There Any Drawbacks to Using Prototypes?

The main drawback to developing electronics hardware prototypes is cost constraints. The Entrepreneur states that production costs for developing prototypes in the U.S. could cost anywhere between $10,000 to $100,000.

Smaller companies, startups, and one-person businesses often lack adequate funding to implement preliminary designs of physical products before going to market. Nonetheless, prototyping is a great way to develop products that have the essential qualities, functionality, and durability to thrive in a competitive market.

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