Hoverboard? Still in the Future | Hacker News Reader

Hoverboard? Still in the Future

nytimes.com

74 pointsdeclan40 comments

It was annoying that the article said:

But when the 190-pound visitor stood atop the 100-pound board, one gentle push was enough to send him spinning across the room over a cushion of air.

This is very poor writing since there is no "cushion of air" involved, the air is not supporting the weight of the board and rider, it's a magnetic system after all. It would probably work almost exactly the same in vacuum.

Same reporter on railgun: "And then a powerful cushion of air explodes sending the projectile at Mach 7 towards target further than any other long range weapons in use today.

Well, he is technically right. There is air underneath it, and it could be described as a cushion, albeit a poor one. Remember he's trying to explain it in terms that non-technical people will understand.

Now that their kickstarter is up, people are already streaming in to back it. I bet most of them will completely gloss over this gem of a sentence: "Currently, this surface needs to be a non-ferromagnetic conductor."

While it does have some applications even with that limitation, it's far from a practical hoverboard, and it's very misleading to be talking about other uses of the technology as if it already exists. They seem to be getting ahead of themselves by extolling their "design focus" when they don't have the product people expect from them yet, and possibly (probably) never will.

I don't want an hoverboard. I want an hovercar. Replace roads with a sheet of copper and put grass over it.

I don't think you truly appreciate the price of copper. There are copper thieves, but not asphalt ones.

I don't think you truly appreciate the ingenuity of thieves. By the way, I was just passing and wondered if you needed your driveway paving? You see, we have this extra load of asphalt that we didn't need on our last job...

No, it's just that asphalt isn't worth stealing.

The driveway scam is generally done with stolen asphalt from roadway construction. I know this from a professional con artist who has had a long career in this kind of shenanigans.

Yeah, that lowers cost considerably. Copper is attractive even when it needs to be cut out of signal cables. The Norwegian railroad authority is switching to aluminum cables in certain parts of the country to avoid it.

Perhaps it's a cultural thing?

In England there is a scam where builders go door to door offering to fix your driveway. Part of the scam is offering to do it cheap because they have some left over asphalt from a large job and it needs to be used quick.

They then do a terrible job with the stolen asphalt, but cosmetically it looks okay so the householder pays and the crooks leave.

Some interesting rewards in the Kickstarter. https://www.kickstarter.com/projects/142464853/hendo-hoverbo...

I do like the White box idea. I wonder though at the price where they start and if thats going to eat the profit generated. (I don't know, they could be very cheap to produce at scale.)

Having non-skateboarders demonstrate their invention was a poor choice. They seriously lack the balance needed to make this look appealing.

I hereby offer my balance, free of charge if you need someone :)

Exactly what I was thinking...

The thing is it operates nothing like a skateboard at this point. While skaters would likely have better balance, the fact that there is no lateral friction or way to control yourself means they probably wouldn't have looked much better.

Still a cool prototype though.

I'm sure there would be a small learning curve but I am positive I could get used to it. I've done other sports that do not have much lateral friction (on water).

You need resistance to sideways motion (lateral friction?) for this to work.

Yeah, they need to polarize the Lorentz force, then they're good to go.

http://www.nytimes.com/2014/10/21/technology/hoverboard-stil...

The Verge has a better video on the device: http://www.theverge.com/2014/10/21/7025795/riding-hendos-hov...

I guess this needs to operate over a conductive surface? Would saltwater work?

It does, and saltwater isn't conductive enough. The effect degrades the lower the electrical conductivity of the medium in which eddy currents are formed. Pretty much requires something like copper or silver (or gold!) for high enough conductivity to make it work. A superconducting surface works great for this.

How about aluminum?

It should work, but less well. The conductivity of aluminum is more than half that of copper, so I would expect their 100 lb board which can hold a 190 lb person to be able to hold at least a 100 lb person.

The thickness of the metal plate also has some effect, but it is limited, and I would expect that their plate is already thick enough for additional thickness to not matter. I don't think that you can compensate enough for material conductivity with thickness, but I don't have time to research that at the moment.

Does anyone know if the physics checks out? Can producing an eddy current create a repelling force that levitates? Why hasn't anyone thought of this before?

Is the same principle as electromagnetic forming that is commonly used in industry - http://en.wikipedia.org/wiki/Electromagnetic_forming

Yeah, it's a Lorentz force, an induced current->field that repels the excitation field. More here:

http://en.wikipedia.org/wiki/Eddy_current

I think it has been 'rediscovered' many times, but it's hard to market, since it requires a special platform to run on (even if it's just a sheet-o-metal). Sorta like how you can build a hovercraft out of a leaf blower and some plywood, but generally not used in every day life, despite the coolness. If we could have long, smooth sheets of copper laid out, I'd be pretty thrilled; might need to grab an asteriod to make it cheap enough, though.

Also, nice nick; possibly the most apropos I've seen in a while :)

Maybe in future children will play with hoverboards ON asteroid made of copper? :D

Drop a strong magnet down a copper tube - it's freaky the first few times you do it.

http://youtu.be/keMpUaoA3Tg

Copper is a bit expensive! I'd love to know where to get a bit of pipe like that.

Stick four or five of these on a skateboard:

http://www.jetcatusa.com/p60.html

I don't really get why a hoverboard would be better than a regular skateboard anyways. It's a solution looking for a problem.

The ground's surface wouldn't matter - skateboards are generally limited to (or at least work best on) flat, smooth surfaces.

Because hoverboard. That's really the beginning and the end of it. It's not supposed to be better at anything. It's a hoverboard.

it get get around this: http://www.skatestoppers.com/Images-Photopage/install09.jpg :p

I thought I just read a few months ago that we'd have superconducting EM drive hoverboards any day now?

How disappointing...

Does anyone know how built in batteries can provide enough power to support a 190 lb person?

Someone forgot Newton's 1st Law of Motion, and it's evident in all these videos. In other words: It's impossible to steer a device like this .

Nonsense. It could be steered (well, maybe rotated) with flywheels :)

If it is impossible to steer a device like this, explain the whitebox+ with directional control from your smartphone that they are offering.

The thing works on repulsive eddy forces that always oppose the field you create. If you angle the field, you should get lateral forces.

edit - thinking about it, you do not have to angle the field, you just need to move it. Also, if you move the device it should automatically resist the motion due to the currents created. With some accelerometers feeding back into controlling the motion of the field, it should be even be possible to give the device what feel like edges to make it behave like a snowboard.

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