Tony Fadell explains early iPhone development process

"The first thing was, we wanted to make an iPod Video product work better. So let's put a big screen on an iPod, remove the wheel, and make the wheel virtual, so you can look at widescreen videos and pictures," Fadell told The Verge in an interview on Wednesday. "Because the click wheel was getting in the way, and we wanted to not make the device bigger, but we wanted to just add a bigger screen, we wanted to try to figure out."

However, the improvement of the iPod wasn't the only thing that Apple had in mind. Initially there was a separate project for the iPhone.

"I don't know if we had the winner product, I think we had the winner design." - Tony Fadell

"Then there was the iPod phone, which would keep the screen small — a lot like that Nokia small screen design. Then we'd just use the wheel as the interface because that's so iconic, " said Fadell. "But what really failed at the end of the day with the iPod Phone was that you couldn't dial a number. Like, 1, 2, 3, like a rotary phone. Everything else was working but the one main thing that didn't work was dialing a regular number — it was so cumbersome."

Working with Steve Jobs on the iPhone

Fadell claims that Steve Jobs was the biggest proponent of the click wheel for dialing numbers on the future iPhone.

"We tried everything. We tried having little buttons on the click wheel so you could click," said Fadell. "There was a Nokia phone where they had a circular pattern for the numbers, in hard buttons, and Steve was like "Go make that work." So we tried that."

The team ultimately had to tell Jobs that it wasn't working out from a user-interface standpoint.

"So we were halfway through, like four weeks or five weeks into it, and we said 'This is not working.'" reminisced Fadell "We pushed this for like another four, five weeks to keep trying, and we're saying, 'This is a waste of time.' But we had to be ready, because that's what he wanted."

One vision, different paths

Fadell recounts taking charge of the division in the early stages of development, when the iOS was just taking form, and Apple was also considering an embedded Linux project.

"There was a Linux-based OS that Jon [Rubinstein] and a couple of other people had started, and then there was the reduced OS X that Avie [Tevanian] had started with Scott [Forstall]. They were competing to see which one was better. He and Jon had that battle," clarified Fadell "I took over and we had a few conditions to make sure it could work on the hardware, since macOS was so big at the time."

"Steve was happy and all that stuff," said Fadell regarding the decision. "It was a couple of weeks from the time I took over the division to the time I was convinced that we would be able to move forward with the [iOS]."

The shipped product

"I don't know if we had the winner product, I think we had the winner design," said Fadell. "It was so immediate, when we passed enough of those hurdles that we knew we had the winning design."

Ten years ago Monday, Steve Jobs unveiled the original iPhone during the keynote address at Macworld 2007. Originally slated to have a plastic display cover, the final product had a first-of-its-kind glass multi-touch display, with a 320-by-480-pixel resolution at 163 pixels per inch, up to 16 gigabytes of flash memory, 802.11g Wi-Fi, a 2-megapixel camera, support for the EDGE 2G wireless network, and Bluetooth 2.0.

The iPhone 7, released in September 2016, is said to be up to 120x faster than the original iPhone, and has a 750x1334-pixel display at 326 pixels per inch, up to 256 gigabytes of storage, 802.11ac Wi-Fi, 12-megapixel cameras, 4G network support, plus Bluetooth 4.2. Other features include Apple Pay, and a Touch ID fingerprint sensor.

Fadell and former Apple engineer Matt Rogers went on to cofound Nest Labs, best known for the company's smart home thermostat. Nest and Apple had a close partnership that fell apart in 2014, when Google acquired the company for $3.2 billion.

Last year, a reorganization within Google placed Fadell in charge of the company's wearable Glass project. Fadell also remained in charge of Nest, which is now technically separate from Google under the firm's new umbrella company known as Alphabet.

Fadell announced that he was leaving Nest in June 2016.