Martin Cooper made history by developing the first mobile handset and also making the first call. But he feels the world has become too obsessed with his invention.
The problem with mobile phones is that people look at them too much. At least, that's according to the man who invented them 50 years ago.
Martin Cooper, an American engineer dubbed the "Father of the cell phone," says the neat little device we all have in our pockets has almost boundless potential and could one day even help conquer disease.
But right now, we can be a little obsessed.
"I am devastated when I see somebody crossing the street and looking at their cell phone. They are out of their minds," the 94-year-old told AFP from his office in Del Mar, California.
"But after a few people get run over by cars, they'll figure it out," he joked.
Cooper wears an Apple Watch and uses a top-end iPhone, flicking intuitively between his email, photos, YouTube and the controls for his hearing aid.
He gets his hands on the latest model every time it is updated and gives it a thorough road test.
But, he confesses, with several million apps available, it can all feel a bit much.
"I will never, ever understand how to use the cell phone the way my grandchildren and great-grandchildren do," he says.
Cooper's iPhone –– which he says he likes to use mostly to speak to people –– is certainly a very long way from the weighty block of wires and circuits that he used to make the very first mobile phone call on April 3, 1973.
At the time he was working for Motorola, leading a team of designers and engineers who were engaged in a sprint to come up with the first properly mobile technology and avoid being squeezed out of an up-and-coming market.
The company had invested millions of dollars in the project, hoping to beat out Bell System, a behemoth that dominated US telecoms for more than a century from its inception in 1877.
Bell's engineers had floated the idea of a cellular phone system just after World War II, and by the late 1960s had taken it as far as putting phones in cars –– partially because of the huge battery they needed.
But for Cooper, that didn't represent real mobility.
At the tail end of 1972, he decided he wanted a device that you could use anywhere.
So with the entire resources of Motorola at his disposal, he pulled together experts on semiconductors, transistors, filters and antennae who worked around the clock for three months.
By the end of March, they had cracked it, unveiling the DynaTAC –– Dynamic Adaptive Total Area Coverage –– phone.
"This phone weighed over a kilo –– about two and a half pounds –– and had a battery life of roughly 25 minutes of talking," he says.
"That was not a problem. This phone was so heavy, you couldn't hold it up for 25 minutes."
That very first phone call didn't have to be long. It just had to work.
And who better for Cooper to call than his rival?
"So here I am standing on Sixth Avenue (in New York)... And it occurred to me I had to call my counterpart at the Bell System... Dr Joel Engel.
"And I said, 'Joel, this is Martin Cooper... I'm talking to you on a handheld cell phone. But a real cell phone, personal, portable, handheld.'
"There was silence on the other end of the line. I think he was gritting his teeth."
How the cell developed
From brick-sized handsets popular with stockbrokers to intensely powerful computers that sit in all our pockets today, mobile phones have been forged by a half-century of innovation.
1973: Hello, moto
After Cooper's historic call, it takes a further 10 years for the first mobile to be marketed.
In 1983, Motorola starts selling the DynaTAC 8000X in the United States for a cool $3,995.
Nicknamed the brick, it weighs just shy of a kilo and measures 33 centimetres.
1992: 'Merry Christmas'
On December 3, 1992, Vodafone employee Richard Jarvis receives the first text message.
His computer wishes him "Merry Christmas".
The message would one day sell at auction in the form of an NFT in 2021 for $150,000.
Finnish brand Nokia begins a string of innovations that pushes the boundaries of mobile.
In 1997 its 6110 model introduced mobile games to the masses with "Snake".
Two years later, the 7110 is the first phone to use wireless networks for browsing, and the same year the 3210 brings predictive writing to the world.
In 2003, Nokia launches its affordable, robust 1100 model, targeting developing countries. It shifts 250 million units, making it the best-selling phone in history.
2001: 3G in Japan
In 2001, Japan is the first country to benefit from a 3G mobile network, allowing high-speed internet access.
It comes hot on the heels of other Japanese innovations including a phone with video-calling capabilities, the Kyocera VP-210 in 1999, and a year later the Sharp SH04, the first with a built-in back camera.
2007: First iPhone
"Today, Apple is going to reinvent the phone," says Steve Jobs as he presents the iPhone to an adoring crowd in 2007.
He promises an iPod, a phone and an "internet communicator" all in one device, which eventually retails for between $499 and $599.
The App store is introduced in 2008.
The same year, the HTC Dream is the first smartphone released with Google's Android operating system.
2009: Rise of the messenger
WhatsApp launches in 2009 and is quickly followed by many other messenger apps –– Viber, WeChat, Telegram, Signal.
These apps, which use the internet rather than traditional networks, become more popular than SMS in 2012.
Stockholm is the first city to offer users very high-speed 4G coverage in 2009.
2011: 'Emoji' fever
Siri arrives in 2011, allowing users of Apple's iPhone 4S to send messages, set appointments, make calls or even search the internet by simply asking your phone.
Google and Amazon develop competing voice assistants in the years after.
In the same year, "emoji" fever seizes the planet when the tiny faces, sketched in 1999 by Shigetaka Kurita, are integrated into the character library of the iPhone.
2019: 5G, foldables
On April 5, 2019, South Korea becomes the first country covered by 5G with the promise of even faster navigation.
In the same year, South Korean firm Samsung and China's Huawei are the first major manufacturers to release foldable screen smartphones, the Galaxy Fold and the Mate X.