Hacker News Reader

Hacker News

Comment by pintxo | Hacker News Reader

Full thread

pintxo

I am not sure I'd like my phone to do this in my pocket while riding a roller coaster.

View on HN

It looks like it just releases the little arms which are spring-loaded. It shouldn't even open in your pocket.

If you fall with the device, the device thinks it's falling.

From the look of the speed that it opens, yes it would probably hurt if it opened in your pocket.

It depends a lot on how much force the springs exert.

People who downvoted you don't know basic mechanics.

They might know advanced mechanics.

The statement was: If you fall with the device, the device thinks it's falling.

I'd like to know which laws of "advanced mechanics" this invalidates.

There were two statements, this was the other one:

> From the look of the speed that it opens, yes it would probably hurt if it opened in your pocket.

Which is definitely not supported by how that device has been constructed. It's not as if there are large torque servos operating those flippers, you can clearly see the mechanism is spring loaded and so the fabric will contain the device without any injury. Making the springs so strong that you could be injured is silly.

Not necessarily, all it needs is for the legs to be spring loaded lightly. Anything enclosing the phone would simply stop the legs from deploying. Near an eye is a different matter though, the legs move faster than you can react to, and their shape is such that it could be a real problem. At a minimum they should be made from much softer material to begin to address that concern, and the 'top' legs (the ones most likely to deploy near your eye) should deploy after the bounce has been detected.

Would also be pretty easy to use the proximity sensor to avoid that type of false positive.

What would be harder to avoid would be unnecessary deployment when you intentionally toss your phone onto a soft surface, like your bed. (Though the fact that this mechanism is reusable makes that much less of a concern.)

Why would a roller coaster trigger it? Very few of them (if any) cause you to experience 0 G, which is the trigger here.

Even "drop" type coasters usually have enough friction to keep it from being 0 G.

Bungee jumping might do it.

The only one I can think of is Oblivion at Alton Towers. The main feature is a vertical drop section.

Not perfectly vertical, and you still have friction of the wheels on the track.

note that also phones have air friction, so it might not be discernible

Yup. My phones tend to drop along ballistic trajectories, which is rarely a straight line towards the Earth-Moon barycenter ;)

Could use proximity sensors to detect when it’s in a pocket (or next to a face) and not deploy.

How often do you ride roller coasters?

Probably just once with this in your pocket?

Same for bungie jumping, trampolines etc.

In fact, I wonder if this wouldn't be a problem with any fall, say on ice etc.

Having your phone on your person while you are in a roller coaster is something that I can understand but it would not be near your face (are there people dumb enough to take selfies while in a roller coaster?).

But bungie jumping and trampoline jumping should not be done whilst you have anything on your person (keys, phone, wallet). You could easily end up hurt even without an airbag.

The answer to "Are people dumb enough to take selfies doing X?" is "If there is no (implied) IQ test to get to do X, they will sooner or later."..

It's a sorry state, and as far as trampolines go, I'd consider it find as long as it does not impair your movement or hurt you if you land on the pocket, and it's tight enough to not fall out of the pocket if you were to walk on your hands upside down.

are there people dumb enough to take selfies while in a roller coaster?

I can't find the exact photo at the moment, but I remember one of ads for a phone I came across did contain one.

Also, a quick search for "roller coaster selfie" shows exactly what you'd expect...

Most (all?) roller coaster operators require that you have no phone in your pockets before you sit down. It’s not just the risk of an idiot trying to take a selfie, the phone could simply come out of your pocket during the ride.

High speed impact x gorilla glass x crowds = ugly.

I've been on dozens of coasters across multiple parks and I've never seen one that requires you to remove your phone from your pocket before riding.

Loose items like hats, jewelry, flip-flops, sure. Items in your pocket? Not so much.

I rode 12 different roller coasters this past Monday, not one required empty pockets, however it was an option to store pocket items in a bin on one of them. I'm realizing as I write this you probably mistyped your... I did take a picture of the Lake Erie islands, and one of Sandusky Bay on a coaster, was probably not wise however. It was interesting to see how Cedar Point is using Samsung smartphones phones & GearVR headsets to breath new life into one of it's oldest coasters, by far the coolest VR experience I've tried.

Use light sensor in addition to accelerometer.

Not reliable enough for a mass production solution.

What if you drop it at night?

Phones have pocket detectors already. They use infrared distance sensors mostly.

...and the complexity increases by orders of magnitude. With all the decision logic, the added latency might register as "drop...thud...oh hey, weren't we supposed to deploy something?...legs deploy"

I think you grossly overestimate how much latency another variable to the decision logic would add. Keep in mind that this is computed onboard, not by bluetooth to the phone or anything. So it can be done by a dedicated chip checking 100 times a second if accelerator value ~= 0G and a proximity sensor detects nothing.

The previous comment noted that "phones have [suitable sensors]". Duplicating those in the board would work, but even then - checking every 10 ms will mean a far higher battery drain (and yes, we've just complicated everything at least one order of magnitude, this point still stands).

The system seems to be a cover with no connection with the phone itself. It relies solely on the internal accelerometer so basically it can trigger the deployment if you jump or find yourself in any 0G situation even for a short period of time (it looks very sensitive anyway).

Reply on news.ycombinator.com