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Show HN: We put an iPhone on the front wheel of a car

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Re: Show HN: We put an iPhone on the front wheel of a car

#81

Post by sliverstorm »

jacquesm wrote: post #75
sliverstorm wrote: post #72

Earlier quoted context omitted.

Crowbars & sledgehammers aren't power tools. It seems much more reasonable to use those without significant PPE.

Hah. Wait until you get a nice long steel nail that jumps away on you from the crowbar just as it exits the wood and embeds itself 2" deep in another piece of wood. if you're lucky. Or when a sledge hits a really hard pebble just off the side of a solid wall and it gets catapulted out. Sledges, crowbars and pickaxes are really dangerous tools and especially if you should wear goggles at a minimum, and probably a helm…

I absolutely buy they are dangerous, but are they as dangerous as a chainsaw or big angle grinder? I'd take a nail 2" deep in my leg over a chainsaw in my leg any day of the week.

(Personally I'd wear PPE with either type of equipment)

Re: Show HN: We put an iPhone on the front wheel of a car

#82

Post by rodw »

What would happen if you put the camera closer to the outer part of the wheel, rather than nearly centered on the hub?

Could Horizon still create a stable-ish video out of that (where the position and rotation of the image are both changing rapidly), or does this require a relatively stable position to work this well?

(I have no particular dog in this hunt, I'm just curious.)

EDIT: I see that Kayou asked the same question, probably in a smarter way, here: https://news.ycombinator.com/item?id=7904992 but I don't see a response from petrakeas or stelabouras yet, so I'll keep my question here even if it is a little redundant.

Re: Show HN: We put an iPhone on the front wheel of a car

#83

Post by Retric »

jacquesm wrote: post #78
Retric wrote: post #59

Earlier quoted context omitted.

11k RPM is not as fast as you might think. That 660,000 RPH * ~8 inch diamiter circle. So outer edge is 3.14*8inch/12/5280 ~= .0004 miles per revolution or 260MPH. But the center is stationary so actual force is a little less than you can throw it. Edit: Camera is not centered on the iPhone. So if you center the camera it's worse than that. I would personally not stand anywhere near it.

The very fastest fastballs are ~100 MPH. So 260 is not 'a little less than you can throw it', what will happen is that it will get dislodged on one corner, do a partial spin and then come flying at you (if it doesn't break up before that). I'd really hate to be hit with anything at 260 MPH, especially not with a phone. Those things are hard!

That's why you want something that functions as a Shear pin. Basically, you don't want to have it attached in such a fashion that it could gain those kinds of speeds.

Re: Show HN: We put an iPhone on the front wheel of a car

#84

Post by Retric »

jacquesm wrote: post #76
Retric wrote: post #70

Earlier quoted context omitted.

I have used a 11k RPM grinder, not that I would have called it small the thing was like 10 pounds. So, I can can see how they might be harder control with newer motors and swapping steal for plastic. Backing up, being safe with power tools is IMO more a mindset than a set of safety equipment. As such you need some understanding of the forces involved. Not, just to be safe right then but so you don't get lulled into a…

You have absolutely no idea what an unbalance of even a few grams will do at those rotational speeds. The thing will escape your grip even if you're quite strong if you're not holding it very tightly.

I don't think anyone was seriously considering trying to hold it. My comment was more in line with "The iphone will desintegrate due to the forces involved and the shrapnel will cause serious injur". Granted, those disks can shatter and I assume an iPhone may also shatter, but saying it will is a different.

PS: I am going to leave this alone. It's dangerous, but I do hope someone posts a video of this at some point.

Re: Show HN: We put an iPhone on the front wheel of a car

#85

Post by Udo_Schmitz »

jotm wrote: post #64
Retric wrote: post #59

Earlier quoted context omitted.

11k RPM is not as fast as you might think. That 660,000 RPH * ~8 inch diamiter circle. So outer edge is 3.14*8inch/12/5280 ~= .0004 miles per revolution or 260MPH. But the center is stationary so actual force is a little less than you can throw it. Edit: Camera is not centered on the iPhone. So if you center the camera it's worse than that. I would personally not stand anywhere near it.

Have you never used a small 11k angle grinder? Those things try to jump out of your hand even worse than the big 6k RPM ones (without soft-start, of course).

Happened to me 20 years ago while sanding wood flooring (the edges). The angle grinder got stopped by a brick and flew out of my hand. I'm not a strong person but seriously doubt anybody could have held to it. Moved totally erratically through the air and scraped my knee just so, but I still can feel the shock. Taught me to respect even small power tools.

Re: Show HN: We put an iPhone on the front wheel of a car

#86

Post by jacquesm »

sliverstorm wrote: post #81
jacquesm wrote: post #75

Earlier quoted context omitted.

Hah. Wait until you get a nice long steel nail that jumps away on you from the crowbar just as it exits the wood and embeds itself 2" deep in another piece of wood. if you're lucky. Or when a sledge hits a really hard pebble just off the side of a solid wall and it gets catapulted out. Sledges, crowbars and pickaxes are really dangerous tools and especially if you should wear goggles at a minimum, and probably a helm…

I absolutely buy they are dangerous, but are they as dangerous as a chainsaw or big angle grinder? I'd take a nail 2" deep in my leg over a chainsaw in my leg any day of the week. (Personally I'd wear PPE with either type of equipment)

How about that nail in your eye?

Really, I can't stress this enough, the kind of energy you can imbue a 4" nail with using a crowbar is something fierce.

Or maybe the crowbar would just fly up and split your head open. 4' of nice steel makes one hell of a spring.

Big angle grinders are actually safer than small ones... until the disks shatter, then you have a real surprise. Circular saws will do fun stuff as well every now and then, they just love it when they get pinched in the cut. So you have to plan how the material will warp before you start cutting otherwise it might cause the dangling part to squeeze shut the cut (when you want the opposite).

Chainsaw in your leg? Not good. Wear ballistic protective covering and you should be fine. The clutch in your saw won't like it one bit but should you ever need it you'll be very happy you spent that money, and a clutch is so much easier to replace than a leg.

With a grinder you want to wear safety classes, no gloves (so you can't get caught). For chainsaws there are as many opinions on safety as there are chainsaw wielders. Even the pros are surprised every now and then, usually not by the saw but by the tree.

The best advice I can give you for saws is don't use one with too little power and keep it sharp at all times (and that goes for all edged tools). Wear a helmet with a screen and ballistic gear (pants, jacket).

If you're super experienced then you can make up your own mind and you'll likely disagree with all of this :)

Re: Show HN: We put an iPhone on the front wheel of a car

#87

Post by jacquesm »

Retric wrote: post #84
jacquesm wrote: post #76

Earlier quoted context omitted.

You have absolutely no idea what an unbalance of even a few grams will do at those rotational speeds. The thing will escape your grip even if you're quite strong if you're not holding it very tightly.

I don't think anyone was seriously considering trying to hold it. My comment was more in line with "The iphone will desintegrate due to the forces involved and the shrapnel will cause serious injur". Granted, those disks can shatter and I assume an iPhone may also shatter, but saying it will is a different. PS: I am going to leave this alone. It's dangerous, but I do hope someone posts a video of this at some point.

I have a hard time envisioning the kind of hold-down that would be required to hold a smooth iphone onto an angle grinder. That's going to be a really neat bit of engineering. And then of course the guts of the iphone will die anyway, I seriously doubt that it was designed with that kind of abuse in mind. But we can place bets on how many seconds it will last.

Re: Show HN: We put an iPhone on the front wheel of a car

#88

Post by ddt »

NAFV_P wrote: post #68
binarymax wrote: post #2

I have some serious sea legs and almost never get motion sickness. The fullscreen youtube vid got me. Great experiment.

The video did make me feel quite queasy, but it is not as bad as Descent [0]. [0] http://en.wikipedia.org/wiki/Descent_(video_game)

Oh man, so many memories of giving motion sickness to my friends and parents watching me play Descent.

Re: Show HN: We put an iPhone on the front wheel of a car

#89

Post by stelabouras »

rodw wrote: post #82

What would happen if you put the camera closer to the outer part of the wheel, rather than nearly centered on the hub? Could Horizon still create a stable-ish video out of that (where the position and rotation of the image are both changing rapidly), or does this require a relatively stable position to work this well? (I have no particular dog in this hunt, I'm just curious.) EDIT: I see that Kayou asked the same que…

Horizon corrects the wrong orientation regardless of the translation/position of the device. Small translation differences along the X or Y axis can be corrected by the stabilisation algorithm. Large translation deltas, however, cannot be corrected.

So, if you put the iPhone on the outer part of the wheel you will most probably get a horizontal video that will end up showing your scene moving up-down, left-right.

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