Clive Sinclair, the inventor and entrepreneur who was instrumental in bringing home computers to the masses, has died at the age of 81.
Sinclair invented the pocket calculator but was best known for popularising the home computer, bringing it to high-street stores at relatively affordable prices.
His daughter, Belinda, said he died at home in London after a long illness.
Sinclair left school at 17 and worked for four years as a technical journalist to raise funds to found Sinclair Radionics.
In the early 1970s, he invented a series of calculators designed to be small and light enough to fit in the pocket at a time when most existing models were the size of an old-fashioned shop till.
“He wanted to make things small and cheap so people could access them,” his daughter said.
His first home computer, the ZX80, named after the year it appeared, revolutionised the market when it appeared in 1980, although it was a far cry from today’s models. It was about one-fifth of the price of other home computers at the time.
It sold 50,000, units while its successor, the ZX81, sold 250,000.
Many games industry veterans got their start typing programs into its touch-based keyboard and became hooked on games such as as 3D Monster Maze and Mazogs.
The ZX80 and ZX81 made him very rich: in 2010 Sinclair told the Guardian: “Within two or three years, we made £14 million profit in a year.”
In 1982, he released the ZX Spectrum 48K. Its rubber keys, strange clashing visuals and tinny sound did not prevent it being pivotal in the development of the gaming industry. Much-loved games – now in colour – that inspired a generation included Jet Set Willy, Horace Goes Skiing, Chuckie Egg, Saboteur, Knight Lore and Lords of Midnight.
Sinclair became a household name as his products flew off the shelves – his company the first in the world to sell more than a million computers – and he was awarded a knighthood in 1983.
But he would also become synonymous with one of his less successful inventions – the Sinclair C5 – which would cost him financially. The C5, a battery-powered electric trike, was launched in January 1985, with Sinclair predicting sales of 100,000 in the first year.
But it flopped, and Sinclair Vehicles found itself in receivership by October of the same year. . The following year, Sinclair sold his computer business to Amstrad.
Belinda Sinclair said: "It was the ideas, the challenge, that he found exciting. He'd come up with an idea and say, 'There's no point in asking if someone wants it, because they can't imagine it.' "
Even his failures – notably a pocket sized TV and a pack to convert a bike to electric power – proved precusors to today's ebikes and practice of watching video streams on phones.
But he did not make personal use of his own inventions. His daughter said he never had a pocket calculator as far as she knew, instead carrying a slide-rule around with him at all times. And he told interviewers he used neither a computer nor email.
Businessman Lord Sugar paid tribute to his "good friend and competitor" on Twitter, writing: "What a guy he kicked started consumer electronics in the UK with his amplifier kits then calculators, watches mini TV and of course the Sinclair ZX. Not to forget his quirky electric car. RIP Friend."
Elon Musk, the Tesla and SpaceX chief, commented on Twitter on an article calling Sir Clive the father of the ZX Spectrum: "RIP, Sir Sinclair. I loved that computer." – Guardian / PA