iYo Yo-Yo almost certainly doesn't work

Aww cmon!
Electromagnetism? Would work a treat with a yo yo!
I'm buying one of these as soon as it's out..

What do you mean it wouldn't work? Do you have any understanding of generating power whatsoever? Didn't think so. So don't pass judgement when you obviously don't know what the hell you're talking about.

This could easily work. Yo-yos turn a lot, really fast, they could most certainly generate power.

It might be a bit impractical, but it's cool, and to say it wouldn't work is flat out ignorant.

This doesn't seem efficient to charge an iPhone, you'd have to "yo Yo" for hours for a full charge probably and as soon as it starts collecting dust n stuff, I can see a big tangled mess with no more "Go" left in the "YO".

Seems like a big silly crackpot invention to me. we'l see and yes, the Apple logo on it will NEVER fly, and Apple probably isn't going to purchase the thing either, so let's keep it simple shall we and just have fun with our "Duncans". ;-)

Back when I was at school 10 or so years ago, here in the UK, Yo-Yos were all the craze. There were loads of types, but some had little LEDs on them that flashed as they spun around. Presumably these worked on a similar principle. That said, LEDs are very low power...

Except that for the yomega the "still" part is still because of inertia and a good bearing. Once you add in the generator parts it's going to want to go spinning with the moving parts pretty quickly.

I took a look at the gadget that Niklas pointed too and that's exactly what I had in mind. Kind of a two-handed yo-yo.

Don't you just hate it when someone steals your idea!

You are actually skeptical about the feasibility of hand-cranked products, like this one, which is being produced and sold?

http://www.potenco.com/products

Unfortunately, physics is against him. He has a rotating part and a non-rotating part. That's good because you need to move the magnet past the coil (or vice-versa) in order to generate the electricity. But there isn't anything that will keep the non-rotating part still. And in a generator there is a lot of "magnetic friction" (I think it's called hysteresis) between the parts. If you have ever been to a science museum where they have a hand-crank generator; when there is no load it's easy to crank, some load is harder, and full load it takes a lot of effort. Well, the yo-yo has to do that work too to generate the electricity.

Now, if he changes it to one where you hold the yo-yo in one hand and pull the string out with the other, that might work. But it's not going to work doing loop-the-loops and walk-the-dogs!

Nobody believe you could charge a laptop by turning a crank, either.

uh.. i believe it could work.. work out something like the yomega fireball/brain, and 1 throw can have the thing spinning for over a minute.. and have it charge an internal battery