I had the chance to ask a few questions to John Teel, founder and lead engineer at Predictable Designs about design reviews on new electronic hardware products. He helps companies who are designing and developing new electronic hardware products.

If you are not sure where to start, you can grab his ‘cheat sheet’ (15 steps for developing your electronic product).

Q: In your ‘cheat sheet’, you suggest an independent design review. What insights does such review typically yield?

The insight you will gain from an independent design review may be minor or major, but nonetheless critical.

Sometimes such a review might only alert you to small design errors, but nonetheless being able to fix these errors before prototyping can save you a tremendous amount of money and time on prototyping. It is always much cheaper and easier to fix any issues before you actually pay to produce your first prototypes.

On the other hand, sometimes the insight you’ll gain from an independent design review can be major.

For example, I have reviewed many designs that would never be functional as currently designed. This may be the case if you are new at circuit design and attempting to do it yourself, or it may be the case if you have hired an engineer that doesn’t really know what they are doing.

Many times my reviews have served to alert people that the engineer they have hired is not a good choice and lacks the specific engineering skills needed to design a new electronic product. Not all engineers are created equal.

Q: What would typically be considered in such a review? Design for Manufacturing, Design to Cost…?

Typically I recommend three levels of design reviews.

First is a review of the components selected for production (BOM). This ideally really needs to include a review of the cost for each component so you can optimize your product’s manufacturing cost. Unfortunately, most designers totally neglect cost when choosing components, and most engineers tend to focus solely on the component performance and specifications.

Next you need to also get the schematic design reviewed, and finally, a review of the Printed Circuit Board (PCB) layout is necessary.

Q: You go straight from ‘Create 3D model’ to ‘build looks-like prototype’. Does it sometimes make sense to make incomplete prototypes to test certain assumptions?

Yes, there are times when you may also need to create some simple prototypes to test certain assumptions.

For example, you may want to create a crude prototype of your product from clay so you can quickly get a sense for how the product feels in your hand. That is difficult to get from a 3D computer model, and clay prototypes are much more simple and cheaper than a full 3D printed prototype.

Q: The last step in the development process, in your words, is ‘Evaluate prototype, revise as necessary’. On average, for a product of medium complexity, how many iterations are needed?

On average I would expect to need at least 3 prototype iterations.

This is true for both the product’s enclosure and the electronics. More advanced products may require as many as a dozen prototype iterations in order to get everything just right.

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You may contact John at ‘john (at) predictabledesigns.com’ if you have further questions on this topic, or if you need his help. Thanks for speaking with me John!