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The product design life cycle

When you move on to focus on the outward appearance of your device, you must consider its design features. You can iterate over these in the same way as you did with the device’s hardware features.

Same process, different considerations

When you are creating a design for the housing and deployment of your device, you can follow the same process you have been using for hardware and functionality design: the analyse, design, build, test life cycle we explored last week.

The main difference is the things you will take into consideration to guide your design. At the hardware stage you were focused on pure function, simply asking, does this thing do this task? That approach works well for hardware, as it can stop you getting lost in overcomplications. When it comes to design and housing, how you feel about the design is important, and this means the tests are not as clear-cut.

Design considerations

To illustrate these differences in thinking, we’re going to go over the steps for the design life cycle again, this time considering them from a pure design perspective.

We have included some questions to ask yourself at each of the stages. Use them as a jumping-off point to ease you into exploring each stage. If you can confidently answer them all, move on to the next stage. You will find that more questions crop up than the ones we have listed.

Understand the problem

Once again, you should break your process up into smaller problems that can be iterated over to build a solution. In week one we decomposed the smartwatch and discussed the strap as a design feature. One problem for the designers of that strap could be the matter of how it will fasten, and they would apply this process to find a solution.

When analysing the problems, consider what your restrictions are, and whether they are about your budget or your skill level. Knowing your limits and how far you can go with your design is a good place to start. You’ll then have to work within those limits, or find ways to get around them.

When it comes to aesthetic design, consider what your particular user persona would want to see in a particular feature, and how you can best meet those expectations. Get inspiration from other devices. Including some familiar elements in your design will make users feel confident when they see it, as they will recognise those features.

  • What challenges will you have to face (in budget, knowledge, or access)?
  • What is the simplest solution you can think of? Will it work? Why? Why not?
  • What does the user want to see in this feature?

Design a solution

Next, you start designing. Drawings are your friend here; sketching something out is a quick way to see if you understand how the design will be put together. Designs as they appear in your head can be misleading, and just a simple sketch will help you visualise the design and start to notice any gaps in your thinking.

Feel free to look at other designs; services such as Thingiverse have thousands of designs for you to browse and get inspiration from. You don’t need to reinvent the wheel, especially if you are not intending to sell your product.

  • What impression are you trying to give?
  • Can you tell what this device is just by looking at it?
  • How will you make this? How long will it take?
  • What materials should you use?

Build the solution

Start with prototyping materials (more on this in the next few steps) and try to build something quickly. Physically making your design is the best way to see what works and what you need to improve.

  • What challenges did you face when making this build?
  • Does everything work the way you thought it would?
  • What could you improve on in the next run?
  • What do you like about this version (this one is important)?

Test the solution

Once you have completed your first build, test it against your initial criteria. Think carefully about how the design makes you feel. If you are proud of it, try to identify the things you particularly like. If you think it is ugly, explore why you feel that way. Always look for good things or positive changes you could make; there is little benefit in focusing on the negatives.

  • Has your build succeeded in fulfilling the tasks?
  • How do you feel, looking at your design?
  • Is it durable? What could cause the design to break?
  • Can any weaknesses be removed?


You should repeat this process a few times, both while you are prototyping and while you are working on creating a complete product. Iteration in the prototyping stage is particularly important, as you will be learning lots of valuable lessons about the feasibility of your designs.

Design thinking

  • What makes a design good?
  • How do you know when to stop prototyping?

Share your thoughts on these questions in the comments section.

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This article is from the free online course:

Design and Prototype Embedded Computer Systems

Raspberry Pi Foundation