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Bringing a product to life through a Form Factor Prototype

In this series of posts on prototyping, we explore how wearable technology is created. Through tried and tested prototyping iterations, we look at how to deliver game-changing wearable technology products from idea to mass production.

Every product is different, but the processes for creating them share many similarities. Choosing appropriate prototyping for a given stage of development is key. Coupling this with deploying a wide range of available prototyping technologies and techniques will rapidly deliver impact, reducing risk in a controlled way and stress-testing the product proposition at each stage.

  1. Feasibility Prototype

  2. Form Factor Prototype

  3. System Prototype

  4. Concept Prototype

  5. Production Prototype

Why a Form Factor Prototype?

Whilst Functional and Feasibility Prototypes are excellent at advancing important elements of a future product, addressing the Form Factor Prototype separately, confirms how the future product should look, feel and be worn. This also sets targets for future miniaturisation of the electronics and battery size optimisation. In combination, this makes the commercial and user proposition much clearer, engaging stakeholders and investors.


Proving that your product idea makes sense can often be crudely split into two categories. Firstly that it works in a way which adds value to users and second that they feel attracted to using it. The latter has all sorts of ramifications in terms of fashion, social conditioning personality type, accessibility and other broad UX dimensions. Form factor considerations go way beyond making a product look nice.

Users need to emotionally engage with a product, it has to represent real value both functionally and fit with their values and the way they live their lives. Separating design and technical development into parallel strands allows the whole proposition to be brought to life, before investing in the final integrated version. Reassuring users that a functional prototype will look nice later is asking a lot of most stakeholders and there really is no excuse for this when we consider the prototyping tools we have at our disposal.

Examples of this prototype in the real world

Form factor exploration, development and testing can start with extremely crude foam models and extend all the way to non-functional, but production realistic versions of the product, with the correct materials and surface finishes. Each stage of form factor development allows certain types of questions to be answered, including materials selection, ergonomics and mechanical factors. We also apply these principles to the sizing of products, where several sizes can be user-tested to find the right choice for a specific demographic or to pin down a fixed product dimension or shape.

User testing and validation

User testing of a Form Factor Prototype can be a joyful process, where discussion and qualitative feedback can be both pragmatic and direct, leading to specific design decisions. However, it is often also generally enlightening in terms of the sense of understanding derived from contact with the real world. Even things like how users respond to the weight of a product in their hand or when attached to their body can highlight things completely unknown prior to such testing. User testing a Form Factor Prototype is not about large data sets, it’s about understanding where users see friction in their use of the eventual product, so taking into consideration demographics and broad use cases is very important in this testing phase.


Cost and value for money discussion

Designing a solid model version of the product is considerably cheaper than a full scale product prototype. Firstly because the CAD design is simpler and more focused on the look and feel, not what happens on the inside, but also because the fabrication process does also not need to pay any attention to the internal dimensions, mechanical factors or complex fabrication techniques. Often a Form Factor Prototype is a one off and so can also have hand finishing applied if appropriate, giving textures and visual effects, otherwise unattainable at prototyping stages.

Physical/Digital/Data nuances

It’s also important to use Form Factor Prototyping for digital touch-points. A user will almost always connect with a wearable product through both the physical device and also a smartphone type interface. These aspects of the user journey are extremely important and should not be left to chance, or added as an afterthought later. Wireframing is a classic tool for this and we use tools like Adobe XD, Invision and Sketch to bring things to life in short timeframes and with versatility for testing and quick changes.


In conclusion, Form Factor Prototypes are an essential part of rapid product development. They free the design from the engineering and allow the user a view of the product, embodied in an extremely realistic prototype. Engineering prototypes can never really tell the whole story, so it is with a Form Factor Prototype that we look to uncover the driving factors that will connect users with the future product. This cost effective and enlightening stage should be recognised and planned into the development journey in almost all cases. If a picture is worth a thousand words, a Form Factor Prototype is worth a thousand pictures!

Article by Dr Jacob Skinner, CEO, Thrive Wearables

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