Navigating the design process

This article by LX Innovations outlines the process of electronics design and points out some of the various common pitfalls that can be encountered and ways they can be avoided.

Conceptual development should always be the first stage in any design process and this includes developing a needs analysis and requirements brief, exploring various implementation options, evaluating key technologies and developing a requirements specification and project plan.

These essential services can be provided by LX, a contract electronics design company specialising in the design of embedded systems and wireless technologies. The company has wide experience in a range of different industries and the lessons learned can be used to help designers across the entire process.

The conceptual development phase is used to quantify the feasibility of different options and to explore alternatives as required. To build on any established intellectual property provided by the client or develop entirely new concepts can aid in securing IP in these instances.

Patent research for the client and advice on the technological and legal options available in relation to pre-secured IP is an important activity. The only effective way to approach this situation is to be aware of the IP that has already been secured and to produce client licensed or engineered non-infringing options as appropriate.

While exploring the design concept it is also vital to develop the business case for the product.

In particular, it is important to determine the markets that the client will be targeting. This is significant not only in terms of required certifications (C tick, CE, FCC, etc), but it also affects the way in which a product is designed.

For example, during CE certification the device is subject to relatively aggressive ESD testing. Failure to take this into account in the initial design stages can prove costly.

We have had the experience where a product was designed for Australian markets initially and later the client decided to complete CE certification for the sale of the product in Europe.

Another important part of the conceptual design phase is key technology research. The most appropriate key technologies for each application should be selected, rather than attempting to adapt standard approaches for all products.

In some instances, key technologies are preselected for us by our clients. While this may be beneficial for the client in terms of interoperability with their existing systems, the appropriateness of preselected technology must be carefully considered.

In one instance a client approached us to develop a complex firmware application using a preselected flash-based microcontroller. The device had been chosen based on its market penetration and price, which were critical to the success of the project.

It was evident that fitting all required functionality into the selected device would not be possible despite factoring in an efficient compiler and aggressive optimisation of the code.

In another instance a client requested that we use Bluetooth to implement a low power, remote-control system for a commercial device. In this situation the choice of technology was immediately identified non-ideal and we were able to suggest a much more suitable low-power technology for the application.

Technology must be selected to suit the particular application for which it will be used. This may not always be the most obvious choice, so it is always worth considering different options carefully before the design phase.

The conceptual development phase, while often underestimated, can reduce costs further in the development cycle. It can lower design costs, reduce the need for costly design modifications, lower manufacturing and bill of material (BOM) costs and can even lower support costs if the product is designed with ease of use for the end user in mind.

The end output of the conceptual development phase is a specification for the design, an agreed acceptance test plan and a project plan.

The product design phase includes prototype generation, detailed design, system integration and testing and verification. It is the main phase clients typically consider when approaching the design process for the first time.

The importance of prototyping is often overlooked in the electronics industry. Although beneficial as a test bed for complex products, simpler devices may also benefit from prototyping. The development of rapid, low cost proof-of-concept prototypes can be beneficial on a number of levels.

Such an approach has enabled our clients to secure development grants and significant investment, obtain pre-production sales through demonstrations and has allowed preliminary field testing that shaped later stages of product development through end user feedback.

There are many requirements within the detailed design stage such as user interface, functionality, serviceability, manufacturability, mechanical considerations and environmental considerations.

One factor that is common across nearly all designs is that of bill of material cost optimisation. It is a near-universal requirement to minimise the cost of manufacture while maintaining reliable operation over the required lifetime.

One particular project with which we were recently involved called for an aggressively optimised bill of material and production costs. All possible care was taken during the planning and design phases to ensure that the design would be functional and reliable in the field and the device moved to pre-production manufacturing for testing and certification.

The intended use of the device meant that a simple retractable coiled cable was subject to frequent extension and retraction. Samples were sourced and tested and were effective.

However, during field trials the product was exchanged by the supplier for an inferior one and it failed while in the field.

Thorough testing and verification are fundamental to any design and are crucial to the design of a commercial product that performs to specification. It is beneficial to have a pre-agreed acceptance test plan to ensure all aspects of the specification are met.

Commercial production can be a grey area for clients and is filled with various common pitfalls. The most appropriate manufacturer for a particular product is not always obvious. A key question is whether to manufacture locally or offshore. This can be determined based on the critical success factors of the project.

Where price is decisive (such as in consumer products), offshore manufacturing can offer cost reductions. However, when quality is critical (such as in medical products), Australian manufacturers can often provide a more reliable service.

Test rigs can be extremely useful during manufacturing. In one product, a particular component was selected as an approximate voltage reference. In pre-production prototypes the component proved to be inconsistent.

Rather than increasing the bill of material or changing the design, we designed a device that allowed our manufacturing partner to pre-test and grade devices before assembly. This provided acceptable consistency with minimal effort and expense, while maintaining optimised unit cost.

While commercial production can appear quite daunting initially, it is also just a process. It is important to understand your own needs and to find a manufacturing partner who is able to work with you to meet these needs.

Once a product has been designed, tested and is in a deliverable form, ongoing product and customer support becomes vital.

This support may range from electronic design or firmware revisions to call centre phone support, and we are able to assist clients with the level of involvement that is required in their particular situation.

It is important to understand that ongoing support is not a substitute for conceptual investigation and development. Increased effort in the conceptual stages can often reduce support requirements considerably.

The best support to offer end users is to ensure conceptual development, design and verification is completed thoroughly.

The design process is an exciting process as no two products are the same, nor do they bring the same challenges. However, by understanding common issues that arise, many pitfalls can be avoided.