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  1. #21  
    I think the big functional difference is the gyroscope will provide an absolute value - you are pointing your tablet upwards at a 45 degree angle. The accelerometer will tell that you are tilting it more than you were moments before, but not the actual angle. You could sort of fake it, calculate the tilt over time to come up with a rough guess at which angle the tablet is pointing.

    So for a plane flying application, you can tilt around, and the game can pretend you are moving your joystick, and make the plane move appropriately. But if this was an astronomy application, you couldn't just point your tablet at a star - the tablet would have to guess at which angle you are pointed upwards. Maybe it could do an approximation, but it won't be as accurate as if the phone was telling the application that your are pointing your phone at angle X, pointing y, at location z, at time whenever.

    And you don't want to have the applications do that sort of work, it is better as a service from the OS. The apps need to be able to say - where am I pointing? and let the OS give an answer, either from the gyroscope/gps/compass, or from a calculation based on accelerometer*time/gps/compass.
    KA1
    Visor Deluxe->Visor Prism/Digital Link->Treo 650->Treo 700p->Pre->GSM Unlocked Pre 2 (wifi only)->FrankenPre + Touchpad 32 ->+ Touchpad 4G ATT + ATT Pre3 + 64 White Touchpad... bliss.
  2. #22  
    Quote Originally Posted by ka1 View Post
    I think the big functional difference is the gyroscope will provide an absolute value - you are pointing your tablet upwards at a 45 degree angle. The accelerometer will tell that you are tilting it more than you were moments before, but not the actual angle. You could sort of fake it, calculate the tilt over time to come up with a rough guess at which angle the tablet is pointing.

    So for a plane flying application, you can tilt around, and the game can pretend you are moving your joystick, and make the plane move appropriately. But if this was an astronomy application, you couldn't just point your tablet at a star - the tablet would have to guess at which angle you are pointed upwards. Maybe it could do an approximation, but it won't be as accurate as if the phone was telling the application that your are pointing your phone at angle X, pointing y, at location z, at time whenever.

    And you don't want to have the applications do that sort of work, it is better as a service from the OS. The apps need to be able to say - where am I pointing? and let the OS give an answer, either from the gyroscope/gps/compass, or from a calculation based on accelerometer*time/gps/compass.
    I’m not so sure your statement is correct. I added accelerometer data to an app I wrote, just for testing and to see what data it returns. I took 3 screen shots shown below. In all cases, I am adjusting the numbers with:
    Math.floor(event.accelX * 100);
    Math.floor(event.accelY * 100);
    Math.floor(event.accelZ * 100);

    Screen shot 1… Pre was at rest on my desk. I assume if my desk was 100% level, then x and y would have zeroed out…
    X: 4
    Y: -9
    Z: -98
    beerknurd_flat.png

    Screen shot 2… Pre was held roughly 90 degrees upright, notice the y value…
    X: 0
    Y: -97
    Z: -6
    beerknurd_portrait.png

    Screen shot 3… I kept the Pre upright, but rotated it 90 degrees to (landscape), notice 90 deg. sideways and the x value...
    X: -89
    Y: 3
    Z: -38
    beerknurd_landscape.png

    Roughly speaking , it looks like you can determine what angle the phone is at using the accelerometer…. Compass would be needed to help spinning the phone once upright.
    Last edited by sinime; 02/17/2011 at 10:08 AM.
  3. #23  
    Cool. So the accelerometer gives you absolute values? what is the difference then between the accelerometer and gyroscope? Precision?
    KA1
    Visor Deluxe->Visor Prism/Digital Link->Treo 650->Treo 700p->Pre->GSM Unlocked Pre 2 (wifi only)->FrankenPre + Touchpad 32 ->+ Touchpad 4G ATT + ATT Pre3 + 64 White Touchpad... bliss.
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       #24  
    Quote Originally Posted by ka1 View Post
    Cool. So the accelerometer gives you absolute values? what is the difference then between the accelerometer and gyroscope? Precision?
    Yes gyroscope is for absolute precision
    check out this video with and without gyroscope
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    #25  
    The main differences in regards to phones and applications are:

    Accelerometer - can detect when the orientation of the device is changed and gives a very rough approximation of rotation and tilt (rough being relative)

    Gyroscope - gives very fine feedback of 3 dimensional rotation around it's center (ideally). An application here would be a map where when the phone is held in your hand and you rotate, the application adjusts your direction.

    Most phones and mobile GPS's don't have gyroscopes, they wait for movement (relative time displacement from satellites) to determine your direction of travel. A gyroscope would instantly deliver that without requiring the user to being movement in the new direction of travel.

    Thus, you can see the benefit of a gyro.
    Dan
  6. #26  
    I actually purchased an iPhone 4 (pre-order) from ATT for the simple fact that it had a gyroscope and I had an idea for an app to use it. That night I got home, wrote some code only to find out it was nowhere near as accurate as I needed, promptly posted it on ebay and made a cool $300. I still love my launch day Pre more than that thing.
  7. #27  
    A point that I think is often missed in these forums is the breadth of technology that HP brings to the table. The acquisition of Palm is less than a year old, so many synergies are not yet incorporated. For instance, HP is a major innovator in the MEMS field- which happen to be the chips that drive a tool like a gyroscope:

    "Hewlett Packard Co. (HPQ), a leader in MEMS inkjet technology, also has developed an extremely sensitive sensor that will help find new oil reserves, among other applications."

    Think there might be an engineer or two considering the crossover application to electronic devices? Rome wasn't built in a day, guys..there are some great building blocks in place. The next generation of products may be closer to the vision of game-changing. I know, I know...patience is anything but a virtue around here.
  8. #28  
    an accelorometer measures acceleration and when static a 3axis accelerometer can work out which way down is as there is a constant acceleration of 9.81m/s/s (or 1g).

    a gyro measures the rate of rotation about a given axis. By intergrating (adding successive measurements together) this over time you can keep track of the orientation. The accuracy of this will drift over time as successive errors add up.

    by coupling together a accelorometer, gyro and compass you can get the absolute accuracy of the compass and accelorometer and the responsiveness of the gyro.

    in theory you can also intergrate the acceleration(adjusted for rotation) to track the device through 3D space. It's how submarines navigate underwater. MEMS based modules in mobile phones are not yet accurate to achieve this over long periods of time. They can however be used to augment GPS and allow you to dead reckon through short coverage dropouts.
  9. #29  
    Quote Originally Posted by migs View Post
    It's my opnion that in order to compete with the obvious leaders ios/android, the new HP phones need to meet or exceed all current features and innovations. Well, the gryoscope in the iphone4 and in most newer Android phones is simply put, amazing. It aids in gaming with up to 6 axis control schemes,but most of all the coming augmented reality apps I've seen are down right like magic...
    All this crazy hyperbole and exaggeration people throw around here is unreal.

    No - it's not necessary to be same or better in every feature. And that's rather obvious too because we can see a wide variety of products in the market - most of which sell well enough.
    How many of the most successful Android phones have retina displays for example?
    Can you charge an IPhone with a touchstone charger or directly use a standard micro USB cable for charging and/or data transfer?

    And many features are contradictory. If you want to design a phone with extra long battery life you won't be able to also make it the thinnest and lightest. Because these features collide.

    Last but not least - even if one product could have *all* "features and innovations" it would cost more.

    Products sell well because they hit the right mix for the right price for some segment of the market.

    A gyroscope is nice and all but many users would never know the difference. Same with front-camera for video calling or retina displays or full multi-tasking, etc...

    Normal people don't spend time on geek forums and worry about specs for hours. Normal people try a few models - like one a bit more for any number of personal reasons and don't ever use some of its features.
    Pre -> Pre3 & TP32 -> Nexus 5
  10. #30  
    The iPhone gryo seems more like a gimmick than an actual needed feature, kind of like their "Retina display". It might be nice here or there and it can give marketing hype but probably doesn't end up being worth the extra cost from a manufacturing/performance stand point.
  11. #31  
    Quote Originally Posted by hagster View Post
    in theory you can also intergrate the acceleration(adjusted for rotation) to track the device through 3D space. It's how submarines navigate underwater. MEMS based modules in mobile phones are not yet accurate to achieve this over long periods of time. They can however be used to augment GPS and allow you to dead reckon through short coverage dropouts.
    That's what I was doing on the iPhone 4. The hardware isn't up to par on that thing. I ended up building my own IMU that costs over $600
  12. #32  
    i would argue it's not a gimmick. The combination (dare i say synergy) of the 3 sensors really work well together.

    ...but you are right that most people don't need it most of the time. Likewise the compass, 4G, bluetooth and many other features.
  13. #33  
    Quote Originally Posted by runukraine View Post
    Pretty sure he's just making up words there... Pitch? Roll? Yaw? Come on... if you are going to make things up at least try to sound realistic.

    ;-)
    Those are the 3 axis around which an airplane turns.
  14. #34  
    Quote Originally Posted by Parityone View Post
    Those are the 3 axis around which an airplane turns.
    also known as Euler Angles.

    welcome to geek corner!!
  15. migs's Avatar
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       #35  
    Quote Originally Posted by hagster View Post
    i would argue it's not a gimmick. The combination (dare i say synergy) of the 3 sensors really work well together.

    ...but you are right that most people don't need it most of the time. Likewise the compass, 4G, bluetooth and many other features.

    We say it's a gimmick now, but wait till Apple creates a phenomenal app or game based on the gyro, then hp will wonder why they didnt include it in the first place...
  16. #36  
    Quote Originally Posted by migs View Post
    We say it's a gimmick now, but wait till Apple creates a phenomenal app or game based on the gyro, then hp will wonder why they didnt include it in the first place...
    Nah, the gyros they used aren't advanced enough to make any significant difference in precision. All they really can do is reduce the number of calculations needed with accelerometer and compass data, something that doesn't mater on competing phones because they tend to use faster internals than the iPhone.
  17. #37  
    I'm really surprised some of the posters on this forum don't demand that all HP devices have a TV Tuner and foldaway antenna. Afterall, even those crappy KIRF phones have them, why can't HP?
  18. #38  
    Quote Originally Posted by Orion Antares View Post
    Nah, the gyros they used aren't advanced enough to make any significant difference in precision. All they really can do is reduce the number of calculations needed with accelerometer and compass data, something that doesn't mater on competing phones because they tend to use faster internals than the iPhone.
    depends what they are trying to do. If all you want is rotation rate then you might be right. If you want to do it properly you would combine all the sensors optimally with a kalman filterr. This would involve more calculations, but nothing the phone couldn't easily handle.

    why can't i type the word filterr without it changing to philtre on my pre.
  19. #39  
    Quote Originally Posted by migs View Post
    We say it's a gimmick now, but wait till Apple creates a phenomenal app or game based on the gyro, then hp will wonder why they didnt include it in the first place...
    The Veer is a tiny smartphone targeted at people who want small phones and still have them be capable, and the Pre 3 is a business smartphone targeted at professionals who use it for work. Not really the devices you would give a feature that is only ever used for gaming / bragging.

    The TouchPad has a gyroscope, though, and you'll see that the big slab phone to come later this year, which will be aimed at people who use their phones mainly to game / brag, will indeed have a gyro as well.
  20. migs's Avatar
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       #40  
    Quote Originally Posted by GodShapedHole View Post
    The Veer is a tiny smartphone targeted at people who want small phones and still have them be capable, and the Pre 3 is a business smartphone targeted at professionals who use it for work. Not really the devices you would give a feature that is only ever used for gaming / bragging.

    The TouchPad has a gyroscope, though, and you'll see that the big slab phone to come later this year, which will be aimed at people who use their phones mainly to game / brag, will indeed have a gyro as well.
    I hope so, do you have source article for this?
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