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Show HN: We put an iPhone on the front wheel of a car (evilwindowdog.com)
380 points by stelabouras on June 17, 2014 | hide | past | favorite | 108 comments



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.


Oddly enough I had no problems with Descent / Descent II, but Doom and Doom II wrecked me. I think it may have been because Doom's camera bobbed as you moved to simulate taking steps but Descent's camera was smooth when you moved forward.


You can grab the newest mods, linked from http://descentchampions.org/new_player.php , and find games with other people just about every day.


Not having heard of Descent, I was really hoping it was a game that consisted entirely of falling.


That would be Das Uberleben. http://teknopants.com/games/uberleben/


Also, AaaaaAAaaaAAAaaAAAAaAAAAA [1]. It's a BASE jumping simulator set in a sci-fi universe where it's a huge entertainment sport.

[1]: I'm serious: https://en.wikipedia.org/wiki/AaaaaAAaaaAAAaaAAAAaAAAAA!!!_%...


Potentially looks like a grand vomitarium (and I am terrified of heights), thank you. I've noticed you can download it on the site posted, I'll have to give it a go.


Vomitarium doesn't mean what you think it does - https://en.wikipedia.org/wiki/Vomitorium#Misinterpretation_o...


Interesting, the link you posted refers to a "vomitorium", as opposed to a "vomitarium". I think the latter is a modern colloquialism that hasn't yet been adequately defined, but it sounds great.

[0] is a good alternative.

[0] http://en.wikipedia.org/wiki/Reduced_gravity_aircraft


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


Grew up playing this game - thanks for reminding me of it :)


Why on Earth you had to tell that? After reading your comment I had to go and check out video on my own... Will not do that anymore.


Same happened and I didn't even watch full screen.

Maybe this is a way to test those sea bands that I have that I think generally work. But now I do have motion sickness and felt it almost right away.


I'm getting motion sickness just thinking about it. Haven't even watched yet.


Do watch it, Great Experiment. Got Sick..


For those who do suffer from motion sickness (like me), be aware that while the effect might not be severe (no vomit for me), the headache lingers quite a while (~30 min for me) after watching the video closely full-screen....... Still, a fun experiment.


It looks like they don't account for the rolling shutter on the camera.


I found this to be really incredible. That is some amazing video stabilization technology. If this app was available for android I think I would use it for every video capture I ever do.


This is one of the developers of the app. The Android version will be available in the following month. We are planning on running the experiment on Android devices too!


I've done quite a bit of work doing stabilization on Android. I think you'll find the Camera APIs quite lacking. Are you doing image based stabilization or using sensors? The fact you mention the gravity sensor tells me you're using sensors.

Let me know, I'll be glad to help how I can.


I found this to be really incredible. That is some amazing video stabilization technology. If this app was available for Windows Phone I think I would use it for every video capture I ever do.

(I'm really hoping for the same response that the Android guy got!)


Did you see that it is only stabilizing rotation? If it looks so stable that's because the lens of the iPhone is at the exact center of the wheel. If you were to move your phone along a X or Y axis, I don't think those movements would be stabilized like you could get with a software stabilizer. I guess the main target of this app is people turning their device when shooting a video.


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)


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.


Don't forget that an iPhone has sensors other than the CCD, so it knows when the camera is being twisted / translated around. You would need some depth perception to recover the image, but lucky you, that's exactly what you get if the camera is moving.


I'd love to see them film something while doing this. Maybe a dog or person running next to the car in frame or something. Definitely cool stuff.


I think they are using the middle-out algo for this.


Do NOT load from an iphone. Almost impossible to regain control of your browser!!


Click url bar... Theyre using the new fullscreen api on iOS which kinda sucks IMO.


Thank you for the support! Here are 5 promo codes so you can try our app for free! http://codehookup.com/2291e14c


Absolutely blown away with the demo video (centripetal issues aside) though annoyingly I'm one of those 'other' users, so I have to ask: Anything android related in the pipeline?


"This is one of the developers of the app. The Android version will be available in the following month. We are planning on running the experiment on Android devices too!" - OP.


Absolutely immense -will keep my eyes peeled =D


Missed it :(


This looks like something that iOS will incorporate as a native feature. When they do this, do they usually buy the technology? Or the entire company?


Or just clone it and put the company out of business.


Is that really how apple has been working as of late? It's not like they innovate on the software front all the time.


This would be similar to this acquisition IMO: http://www.macworld.com/article/2083997/apple-acquires-snapp...


Very cool experiment, and even cooler visual results!

One thing though - the tilting of the scene from the phone's perceived variance of the gravity vector is not due to centrifugal force, but due to inertia.

In other words, it's the same reason you're pushed back into your seat when you accelerate, and slam your head into the dashboard and spill hot coffee in your lap when you lock up the breaks.


We also did an experiment with this: http://imgur.com/tdnympM

The same problem existed. So it is not inertia in this case. However, inertia could also interfere with the gravity vector.


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.


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.


Bought the app, seems very laggy on my iPhone 5s. Is this to be expected? I wonder if it is doing the processing as the phone is recording or if it is capturing the accelerometer data and modifying the video after that fact?


It's doing all the processing on the fly while it's recording.


[deleted]


The lagging is because of the iOS's stabilization. You can disable it on the settings ;)


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 ;)


Phones falling off a roller-coaster could be dangerous!


I poked around the website and their projects look awesome, exactly the kind of stuff I'd make if I were more talented. I wish I lived in Greece because I would find these guys and beg them to hire me.


A really cool way of showing off Horizon. Good work guys!


They kept mentioning 'Horizon', took me a couple minutes to realize they weren't talking about the BBC Series heh.


Now this is viral marketing. Great job guys


Does anybody know of any software which can do this for videos which were already captured?



Great job guys. Hope to see this integrated in the iPhone.


That's nausea-inducing.


It'd be really cool to see a side by side comparison with, and without Horizon active


You can if you go to their website - http://www.evilwindowdog.com/horizon/


will there be an API for this?


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


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 plane of rotation may vary rapidly. Too rapid to get out of the way. The iphone will desintegrate due to the forces involved and the shrapnel will cause serious injury.

Please do not do this unless you really know what you're messing with (and if you do then you won't).

On second thought, simply please do not do this. Spinning an iPhone up to 10K rpm or higher is a very bad idea, the label reads 11K rpm max, 850W, those things don't usually have soft-start so it'll just fire up and start throwing things.

Appeal to authority fallacy comes free of charge: I've had a pretty serious metal workshop and have seen several interesting interactions between angle-grinders and various objects in otherwise controlled circumstances, it is astounding how fast things can go wrong. Just having a grinder disc shatter on you can take you completely by surprise even if you know the danger, this is far more dangerous, it is Darwin award material.


Really great points. I think that when working around power tools it is sometimes forgotten how careful you have to be.

Everyone innately knows certain things like "don't stick fingers in light socket" but other things aren't immediately obvious. Perhaps because you are juxtaposing something like an iphone and maybe are focused on the worse case scenario as being a destroyed iphone (in other words the money issue) instead of the iphone flying off into someones face.

I was watching an episode of "Property Brothers" (a typical renovate a house HGTV type show) and was amazed that they were having the owners participate in demolition without using practically any protective gear (while using crowbars and sledgehammers etc.)


> I was watching an episode of "Property Brothers"

I bet this was just for show.


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 helmet too.

And, no, I'm not from the cradle to the grave coddling department.


Yeah I really don't understand the parent making that comment either. As if it's so much work to have some safety gear on.

From busting apart shipping crates as a kid I also realized that in addition to the goggles and helmet you also need boots that can take stepping on a stray nail as well. Not sneakers, definitely not sneakers.


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 :)


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...


I agree your dad is very lucky. That's about as good an ending to that story as you could possibly have. One day I was cutting staircase support (all those triangles you have to cut out) from a 2" x 12" board, the same thing happened and the saw just jumped right out of the cut. I slammed it down before it could get out of control and it still managed to cut a really nasty gash into the wood before it finally stopped moving. Incredible how fast that went from everything fine to literally fighting the saw. Nobody got hurt that time so all is well but still it gave me even more respect for rapidly rotating disks of steel.

I had an angle grinder disc blow on me last fall when cutting through a rooftile, that too was quite an interesting experience. It would have been less of a problem if it had shattered completely but of course one segment on one side decided to hang on. If not for eye protection that would have ended in the hospital for sure.

The one thing I've noticed is that if you rarely work with tools you are really at risk. Then as you work more more with powertools you get more experience, you become a bit more confident and more aware of the risks. That's good.

Then when you're working with them for a really long time two things will converge in a bad way: all that experience and confidence will lull you into a false sense of safety an then the law of large numbers catches up with you, very rare occurrences will happen to you because you are doing it so often.

If you're not paying attention right at that moment you could very well end up in hospital or worse.


"all that experience and confidence will lull you into a false sense of safety"

I've noticed that that happens with many different things in a similar way.

You get confident, you slip up, you work faster, you make mistakes.

When you start out boating (with a new boat) you are oh so very careful.

Then you gain confidence and you start to take more chances. All the sudden things that you could never imagine yourself doing when you start you do. An example might be getting caught in an inlet with a boat during a period when larger boats are all trying to go in or out at the same time and you are tossed left and right.

Programming as well. Say doing a rm -fr foo * in stead of rm -fr foo* and not catching it because you hit return to fast instead of making sure the statement was correct. [1]

[1] I got into the habit of doing for i in foo* ; echo $i ; done and then inserting the rm -fr statement (by using uparrow) just as a precaution to slow me down.


> I got into the habit of doing for i in foo* ; echo $i ; done and then inserting the rm -fr statement (by using uparrow) just as a precaution to slow me down.

I do the exact same thing only I use 'ls foo*' first, and when doing bulk updates / deletes with sql servers I again first do a select and then modify the select once I'm sure it will hit the right rows.


I had an angle grinder disk shatter on me. It didn't hit me, but the force with which it blew was pretty startling.

Yes, I always wear eye goggles with it.

Even so, don't use a grinder without the metal guard, and still try and keep your body parts out of the plane of its rotation.


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.


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.


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 false concept of safety because the overblown worst case you picture did not happen.


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.


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.


A box fan might be a safer alternative. It'd give you the ability to move it around but not the high rpm of a angle grinder.


I want the next "Will It Blend?" to be these people attaching iPhones to a variety of terribly dangerois machinery at high speed. Grinders, chainsaws, motorbike wheels.

Or maybe some safer things too - place it on a record on a turntable and film the face of the DJ doing some mixing?


I want the next "Will It Blend?" to actually answer the stated question — "can this iPhone be used to make a smoothie?" — rather than "can it be blendED?".

Seems like strapping an iPhone to an angle grinder is getting close to answering the stated question...


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 Blended [by this blender]". I want to know "Will It Make a Suitable Replacement for a Blender".


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


I can't wait to see what that's going to look like. Just be careful it doesn't fly off and injure you!


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.


Drive faster god darnit!


oooohh!!! great experiment with great results!!


Why not a GoPro on a wheel?

Edit: I just think I should've googled that first.


I would guess a GoPro doesn't allow Apps nor has the sensors accessible to perform the experiment with an external computer.

[edit] I do wonder why we haven't seen more programmable cameras with the sensors a smartphone has.


... Because this is an iOS app?


...And it's interesting because?


Because the focus of the experiment is an app that records videos while compensating for tilt/rotation (it's not just "hold muh beer while I tape my iPhone to a car wheel!"). I have the app, and find it interesting for its ability to eliminate the inevitable angling of the video, despite being on such an unstable mount (my free-waving hand). By subjecting the app to extreme conditions of rapid rotation, subtle flaws in the compensation process are made apparent - specifically, that the iPhone's gravity sensor gets confused & skewed, that the progressive scanning of each frame means distorting the image (the top of the image shows a view 1/60th or so of a second different from the bottom), and the two together result in a bizarre/unexpected periodic warping of the image. Having this video, the experimenters can go back to the software lab and tweak their image processing algorithms to compensate for these errors and create an even more stable image.

"So what?" you mumble. "It's so subtle nobody cares."

Well, that's actually a big part of why VR failed when it was first introduced a couple decades ago, and why Carmack & Occulus are so successful with it now: they've analyzed the subtle nuances that you don't acknowledge but your brain processes & reacts to nonetheless. Horizon is applying the same attention to detail, and will produce a better product as a result (yes, I do notice those sub-frame distortions in various products almost daily, and would appreciate developers correcting them).


Cool experiment, I just dont get, how that idea came to your mind? - "Oh, man, look, I have an iPhone. Guess what?" - "Yeah, we should certainly put it on a wheel of a car!"


Starting from the second sentence in the article:

"We all know by now that Horizon shoots perfect horizontal videos, even if you rotate your device while shooting! We wanted to stress Horizon’s capabilities by using it under extreme circumstances."


It's so obvious which people commented without reading the article in this thread.


Better title: "Show HN: We put an iPhone on the front wheel of a car and drove really slowly for less than 10 seconds at a time"


50 km/h is fast enough for this experiment if you ask me.


614 revolutions per minute on the tire, assuming a 17" wheel, is still pretty impressive.




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