iPhone accelerometer can't detect constant speed movements

[aesnowb04]

Limitations? Really it's an accelerometer. Does not measure a constant speed. If it senses a movement in a certain direction it can process that it is still traveling in that direction at that constant until another force of acceleration is acted upon it, ie slowing down it could calculate its return to rest. It's a good thing that it has a control at this constant speed anyway because if it did what you want it to do that would mean you wouldn't be able to use your phone on a car, bus, train,

[benoitbergeret]

Funny how many of the commenters seem to not have listened to the commentary... the point here isn't to critize the iPhone's accelerometer, but to point out limitations of using such a device (accelerometer) as input to user experiences. Other solutions exist that can detect linear movement (ie the camera used as a motion sensor, as Visual Cortex developed by Realeyes3D from France back then), which makes for a much better input for UI design.

[2009gibsor]

your retarded. I would elaborate on why but everyone else who has commented already has given basic reasoning.

[inemanja]

its accelometar... if you are going at constant speed you are not accelerating, so when you reach constant speed, there is no accelaration...

[skyfire1129]

If it detected linear movements then it wouldn't work. The Earth is moving around the sun. Want it to detect that? If you could choose to set it relative to something, like the earth, the car your a passenger in, or your own body, then it might work. But you do realize how insane that is, do you not?

[bruujho]

its name is accelerometer not speedometer

[cyberilui]

do you know of any accelerometers (even aftermarket) that detect linear movements? I am trying to develop an idea for a camera invention

[gregslife7]

can you imagine trying to play a tilt game in the car if it did detect constant speeds?

[XxAtomic646xX]

@gregslife7 lol shit would go insane!

[robbyduffy1]

Hence the name 'accelerometer'

I think iPhone4 does measure translation aswell as rotation

[robbyduffy1]

Hence the name 'accelerometer'

I think iPhone does measure translation aswell as rotation

[robbyduffy1]

hence the name 'accelerometer'

Amen

[vipervenom717]

That's not always a bad thing... Imagine if the app was messed up because you were riding in a car. That would be horrible.

[whemak]

Com'on! No accelerometer can measure constant speed movements... 

[moepstaRRR]

omg nOOb

[Dawarr530]

Buy Iphone 4.....

[benoitbergeret]

@whaddafug nope, accelerometers detect acceleration, not velocity. MEMS accelerometers are made of a tiny magnet that moves in a frame when movement occurs. As soon as acceleration stops, they stabilize in their rest position. The movement of the magnet in the frame generates a current in each axis, which is used to detect the presence or absence (basic accelerometers), or the value of acceleration (more advanced chips), together with the direction of movement.

[benoitbergeret]

@theredfandango -- to sample and use acceleration to calculate velocity and direction... you need acceleration. When the movement is close enough to linear, acceleration = 0, which makes it impossible to "calculate" ("estimate" would be more accurate) velocity.

[theredfandango]

If you sample and use the acceleration to calculate velocity and direction, then you can always calculate current position. The only frame of reference needed is the orientation of the accelerometer w.r.t. the casing.

[gentertainments]

but the gyroscope in the iphone 4 can do all this

[PlayWithASmile]

there is something called gravity youg man (;

[PlayWithASmile]

@PlayWithASmile *young

[nurbsenvi]

constant speed = no acceleration....

[Airmark1]

Basic video. But interesting nonetheless.

[GeoNomad]

High school physics? Newton? Something missing in your education?

[paquito43]

Well, you´re actually moving the iphone in a linear constant slow speed...... xD

[bobblima]

@chunter519 Acceleration being defined as... a change in velocity. Right? See, my understanding of physics isn't totally rusty. When we mention linear in this video, we refer to linear speed. As in constant speed. No velocity variation. No acceleration. That might have caused the confusion, apologies for this. Bottom line is: accelerometers are poor tools for building cool UIs and user experience because they detect acceleration, not linear / constant speed.

[IIJazzyII]

It's not possible for the to detect linear movement without some kind of reference. The reason the Nintendo Wii can do this is because it has a sensor you place infront of you tv.

The only possible way to do this on the iPhone is to make the software detect and recognise tiny movements and calculate what you "might" be doing. Basically it would go wrong all the time.

This video is crap.

[whaddafug]

but bob, accelerometers do detect velocity, by default. All you have to do is integrate the values for acceleration wrt time and you have velocity.

It is surprising that the appliacation shows no changes during the initial (from V=0 to V=some value other than zero) acceleration.

Poor instrumentation or poor coding?

[chunter519]

Huh??? How about beefing up your understanding of physics.

It detects acceleration, not velocity or distance. Motion and acceleration can be independent.

If you're moving linearly with acceleration, it will detect it. That's the whole premise of many of the automotive performance apps on the iPhone.

[wiibart]

well it has to do with gravity