Adam Fuda, 30, slammed the popular show - featuring the likes of millionaires Peter Jones and Duncan Bannatyne - which he claims often gives companies "terrible valuations" and misses opportunities.
Cambridge University graduate Mr Fuda, whose gyroscope "for grown-ups" took off on a crowd-sourcing website, said: "Dragon's Den used to be the only way that 'Joe Bloggs' felt he could raise money for an idea.
"I'd struggle to count the number of times my friends have said, 'Hey, you should go on Dragon's Den'.
"But the fact is I'd never go on Dragon's Den to seek funding.
"It makes great TV, and I love watching it, but companies often end up with terrible valuations and if it goes wrong, which it frequently does, you get humiliated on national television. A good PR stunt - but not good for raising capital.
"I also doubt the dragons would have the vision to believe in my product."
Mr Fuda said the dragons missed projects such as the Trunki children's case which was rejected as "worthless" on the programme and is now stocked at John Lewis.
The engineer, from Bristol, raised cash for his gravity-defying Precision Gyroscope on the website Kickstarter and reached his funding target in less than 12 hours. The hand-finished device has already pulled in 140,000 dollars (£88,467) from nearly 2,000 backers.
He and his business partner at Manuka Makers, Glenn Turner, expect the art-meets-science product to take pride of place on desktops, workbenches, and lobby coffee tables in more than 100 countries.
"I used to have a gyroscope as a kid, I always loved it as a toy, and now that I'm a grown up I wanted to have a proper machined, engineered version of it," he said.
"I made the first prototype of it for myself and my friends saw it and they loved it and asked if they could have one too."
He added: "You can give it to someone who doesn't know anything about the underlying science and they'll be amazed by it and you can give it to a scientist who understands everything about it and it's equally perplexing."
He said the success of the gadget, made in London from aircraft grade aluminium and solid brass, proves UK manufacturing still has legs.
A gyroscope is a spinning disc used for orientation and is found in compasses, aircraft and even mobile phones. They are commonly used as an educational toys, with play versions developed as early as 1917.
Since Kickstarter's launch in 2009, more than 4.7 million people have pledged over 769 million dollars (£500 million), funding more than 47,000 creative projects. Every project creator sets their funding goal and deadline. If a project hits its funding goal, all backers' credit cards are charged when time expires. If the project falls short, no one is charged.