Tony Fadell: Former Apple iPod 'father'

Mr. Fadell himself says the decision to shift part of Mr. Forstall's responsibilities to Mr. Ive means that Apple's software design is now in "good hands".

And he has even warmer words for his ex-boss, describing his nine years working with Mr. Jobs as one of the most important relationships of his life. He adds that the experience taught him a lesson that he has tried to put into practice at Nest: success is about much more than a good product.

"It's about every touchpoint where the consumer interacts with the brand," he explains. iPod The original iPod featured a small hard disk and rotating wheel, and was only compatible with Mac computers

"Whether that's at learning about the product, buying the product, using it, servicing it, unboxing the product - all of those places are consumer touchpoints and you need to look at those in as much detail as you do the product-user interactions."