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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

#91

Post by [deleted] »

jacquesm wrote: post #49
petrakeas wrote: post #32

Earlier quoted context omitted.

Developer of the app here. One step ahead of you ;) http://imgur.com/tdnympM

I hope you're joking. If you do plan on doing this then please do it in a suitably strong wire cage, power it on remotely, make sure it is tied down very solidly and make sure nothing you care about (including you, significant others, co-workers, children, pets, possessions etc) is in the plane of rotation because this will fail spectacularly. Keep in mind that if the grinder becomes dislodged or unbalanced that the…

[deleted]

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

#92

Post by btbuildem »

petrakeas wrote: post #32
btbuildem wrote: post #25

Kudos to you guys for trying to solve the VVS problem! For your second experiment, may I recommend attaching the iphone to the disc of a variable-speed angle grinder? You'll get a much larger range of speeds, as well as the ability to aim the camera freely. You'll be able to test how your accelerometer algos handle pitch and yaw IN ADDITION to centrifugal force!

Developer of the app here. One step ahead of you ;) http://imgur.com/tdnympM

Jesus Christ man I was kidding.. don't actually do it. Whatever you attach the phone with probably won't hold, and the phone will turn into a projectile traveling at high speed in a random direction. And if the phone does NOT come off, then you've got your hands on an unbalanced angle grinder going full tilt. Bad news bears all around.

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

#93

Post by fryguy »

robotresearcher wrote: post #55
lutorm wrote: post #53

Earlier quoted context omitted.

Translation of the camera changes the perspective, i.e., the relative positions of different objects in the image. There is no way a piece of software can get rid of that, because the information isn't there in the first place.

The information is there in sequences of images through parallax precisely when the camera translates. We know how to do 3D reconstruction of scene geometry from a single moving camera. https://www.youtube.com/watch?v=fLnd9ucUu9Y Skip to 1:15 to see a textured reconstruction. The first real-time example was Davison et al's MonoSLAM paper of 2007, I think.

Keep in mind that SLAM assumes a static scene. To stabilize a video with a moving target would mean that there's still going to be parallax otherwise you're going to get shadows (see the cool video on Oculus time warp: https://www.youtube.com/watch?v=WvtEXMlQQtI)

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

#94

Post by ar_turnbull »

A roller coaster might be a good experiment if you're looking for an extreme environment that might appeal to more of a mass market. (http://en.wikipedia.org/wiki/List_of_roller_coaster_rankings) Maybe skydiving or bungee jumping?

Or you could go a different direction and attach a phone to a cat. I hear people love videos with cats ;)

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

#95

Post by tempestn »

alxndr wrote: post #77
tempestn wrote: post #73

Earlier quoted context omitted.

What you're describing is the original "Will It Blend": https://www.youtube.com/watch?v=qg1ckCkm8YI&feature=kp

No, I mean "can this iPhone be used to make a smoothie", not "can a blender turn this iPhone into an iPhone smoothie". Take a blender, remove the blades, put iPhones on the spindle where the blades were. Now fire up the blender and throw in some fruits. Will iPhones spinning at $whatever RPMs be able to turn your fruits and wheat grass into a delicious smoothie? The original is actually "Will It Be Blend ed [by this…

Ah yes, sorry, I'm an idiot. I read your original 'rather than' in reverse.

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

#96

Post by robotresearcher »

fryguy wrote: post #93
robotresearcher wrote: post #55

Earlier quoted context omitted.

The information is there in sequences of images through parallax precisely when the camera translates. We know how to do 3D reconstruction of scene geometry from a single moving camera. https://www.youtube.com/watch?v=fLnd9ucUu9Y Skip to 1:15 to see a textured reconstruction. The first real-time example was Davison et al's MonoSLAM paper of 2007, I think.

Keep in mind that SLAM assumes a static scene. To stabilize a video with a moving target would mean that there's still going to be parallax otherwise you're going to get shadows (see the cool video on Oculus time warp: https://www.youtube.com/watch?v=WvtEXMlQQtI )

People are now managing to segment parts of the scene by motion, so that moving cars and pedestrians, for example, are known to be distinct from the camera's ego-motion. The static scene assumption is not strict any more.

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

#97

Post by userbinator »

btbuildem wrote: post #25

Kudos to you guys for trying to solve the VVS problem! For your second experiment, may I recommend attaching the iphone to the disc of a variable-speed angle grinder? You'll get a much larger range of speeds, as well as the ability to aim the camera freely. You'll be able to test how your accelerometer algos handle pitch and yaw IN ADDITION to centrifugal force!

Safety issues aside (as has been well-discussed by others already), the accelerometer won't report more than ~8G. Going any higher than that (which is not hard to do even with a moderately slow rotation) won't be very useful for testing out your app.

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

#99

Post by girvo »

jacquesm wrote: post #86
sliverstorm wrote: post #81

Earlier quoted context omitted.

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 eve…

My dad is a builder, and I've worked for him as a labourer many many times. It really gives you a better perspective on how dangerous all this is...

Anyway, circular saws: dad was cutting some pretty nice wood for a fence. Circular saw hit something in the wood, bounced up, then straight down onto his left hand thumb, severing it entirely.

He then drove to hospital. They reattached it, he was lucky enough to have Australia's best nerve surgeon on call at that hospital that day, and now he's got near 100% movement in it. Very very lucky.

Angler grinders blowing, now that's something that will put the fear of god into you...

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

#100

Post by NaOH »

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)

I've never been a gamer. Except for Descent. And Descent II. I still have them and every few years play them on an old Mac. The queasiness kicks in every time I start playing them again.
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