Invention that needed no specialist knowledge yet was used by the masses.

The Trunki rideable suitcase for kids just scrapes in to the 10 year window. The inventor appeared on Dragon’s Den in 2006 with it.
I don’t know what qualifications he had though.

Bullet Ball

It was invented before that, I should think.

Terry Pratchett’s books often feature The Luggage, a sentient trunk that moves on dozens of little legs. The author says that it was inspired by the sight of a trunk on lots of little wheels. The first appearance of The Luggage was 1983, so presumably wheeled trunks were invented at least a year or two before that.

Why do you think 1987?

I’m pretty sure I first saw them in 1984, so that fits.

I know that’s a joke, but it has to hold not just your $500 cell phone without dropping it, but all the other shape and sized cell phones as well. Also, it has to connect to them via bluetooth with nothing more than a button. If you’ve ever hooked a paired to a device to a phone, you know it’s a bit different for each phone and kind of a PITA if the device doesn’t have a screen.

I’m not saying it’s an engineering marvel and I’ll grant you that the inventor (and the all the knock offs) probably buy the blue tooth module from another vendor) but it also wasn’t invented in an afternoon.

You have to be careful when discussing the notion of “obvious” when discussing patents, as that term has specific legal meanings that aren’t the same as the generally used definition.

As well, thinking that something is obvious, and proving it to the standard needed to deny a patent are two different things. In general, you’d need to find a publicly accessible disclosure of the idea that is clearly dated to before the filing date of the patent application. That’s surprisingly difficult for a lot of these simple “Everyone has thought of that!” type notions.

Speaking of luggage, here’s a fairly recent innovation:

I saw one a few days ago for the first time. One of our male flight attendants had it. Kinda small for our typical number of days on the road, but doable. He was a fun guy with a youthful attitude. Laughing all the way as he sped off through the slowly plodding crowd in the concourse.

Obviously it takes no great engineering skill to come up with the idea. The specifics of making it strong, durable, light, and cheaply manufacturable, plus the effort to market it effectively, all take real expertise.

And I think that’s really the bottom line for the OP’s question. Ideas can come from anywhere including the apocryphal bored housewife. While any genuinely competitive mass market product is going to need expertise all along the design, manufacture, and sales chain.

Which is also why ideas are pennies the ton whereas actual execution commands a high value.

Sorry, didn’t know they used bluetooth. I figured it was a mechanical toggle. Never mind.

It wasn’t invented within the last 10 years but actress Hedy Lamarr invented the basis for frequency-hopping spread spectrum communications, which today is how WiFi works. She had no formal engineering background but pursued it as a personal hobby.

She was awarded a patent which can be seen here with her real name, Hedy Kiesler Markey:

She donated it without compensation to the U.S. government. It was immediately classified as top secret, so her role was not revealed for many years.

Re: the history of wheeled luggage, this New York Times article indicates both 1970 and 1987 as key dates.

I think of the WaterWheel. Might not be a billion dollars, but it is a very simple idea that is in mass production. (Not the energy generating water wheel, the easy way to transport water in poor communities…

Broken link.

From context of the preceeding post, this refers to Heinlein. In which story did he predict the internet in 1938? His first published story was “Life-line” in 1939, although it may have been written earlier. But there’s nothing in it remotely like the internet.

Lots of people can argue they invented the internet (or their supporters can). William Gibson and Pete Townshend come to mind.

I have a set of those foam/rubber pads that you put between car seats so nothing slips through. They’re in Walmart so I’ll bet they’ve sold a few. They may have been ASOTV. I also bet they were invented by someone who just did prototypes cutting up some foam from the fabric store.

Ah, child rearing…
Not sure how much engineering went into the Diaper Genie. Just about every parent has one.

Watch shark tank. They’ve got loads of amateur inventors.

I was trying to develop a nail trimming system for dogs where they would have to dig in a special mix of clay and abrasive sand mix for a treat. I was trying to figure out a way to adjust the hardness of the clay mixture by blending different things in with the soil and clay as the dry clay was a bit too hard for small dogs. The best way was to monitor the moisture level but it required too much customer education and I abandon the project. Very low tech and potentially a very large repeat customer base.

 I made another meager attempt at developing a line of pet products all based on natural animal behaviors, This was going to be an interactive web sight where the customers helped to develop and invent the products. My lack of communication skills killed this one on the vine.

Here’s a few contenders