Inventors are often perceived as eccentric, original thinkers inspired by dreams: but many of the 700 inventors at an international fair in Geneva showed skill, pragmatism and good business sense.
"I can have an idea anytime, anywhere, when I wake up or in a restaurant. There's no rule, ideas come without warning," 53 year-old Mircea Tudor explained.
But that inspiration has translated into the company he runs in his native Romania, which employs 75 people and expects to generate a 20-million-dollar turnover this year.
Last year he won first prize at the International Exhibition of Inventions in Geneva, with a mobile truck scanner he designed to speed up and ease customs checks at borders. It is now marketed as far away as India.
"I invent during the night, when I'm alone and I have left the office," Tudor told AFP.
"During the day there are always daily problems that need to be managed, it's not simple running a business with 75 employees."
Impeccably turned out in a sharp suit, Tudor is a far cry from the scruffy old image of Professor Branestawm made popular by children's books decades ago -- or the temperamental Professor Calculus in Tintin comics.
Tudor said he had always been a something of a problem solver.
But his brand of thinking was honed as a qualified engineer on Romanian railways from the 1980s, when he maintained Western equipment imported behind the Iron Curtain in a bid to keep the trains running.
"It was still the communist period, we didn't have access to technical information or spare parts," he explained.
"I was obliged to invent in order to replace the original parts that were no longer available, that was my formative period as an inventor, a good training ground."
In the early 1990s, Tudor set up his own company and he developed his first invention by 1995.
Now equipped with cutting edge laboratories, the firm makes its own prototypes.
"Inventors are no better endowed with qualifications than others," said David Taji, president of the jury at the inventor's fair.
"But the majority have a practical mind and are handy, and many are self-taught."
Claude Fournier, a former army engineer, was displaying his first patented invention in Geneva, a lightweight shopping trolley that can be slung over the shoulder when folded.
"An inventor is someone who dreams a little, but who likes to follow through to the end and turn his ideas into something concrete," the 67-year-old explained.
"This isn't high tech, but it has a practical side, I invented it by trying to imagine how I could provide some relief for elderly people who go shopping in big cities."
"Making a useful invention, that's the most satisfying thing," he added.
Nevertheless, he said, along the way inventors would often have to make a patent application, set up a company, find suppliers and cope with "quite a few" hurdles.
He ploughed his life savings into his new venture and is pinning his hopes on finding a foreign producer in order to at least recoup his costs.
French engineer Janick Simeray said inventors had to master several jobs at once in order to make a living.
"You need to very well versed in technical and legal matters and have reasonable knowledge of the commercial and marketing side," he explained.
Simeray has patented 120 inventions and reinvests his profits in research. This year he was displaying an electromagnetic plinth that can levitate small household objects.
Explore further: Google teams with Oxford to teach machines to think