Inverted accelerometer on android

aditya · December 2013

The accelerometer axes are inverted on an android device, while it works correctly for the ipad.

Have tried this with our own code as well executing the Box2d_accelerometer project by @ar2rsawseen.

Could someone verify this?

tkhnoman · December 2013

What i know is that this is totally depend on the device.
I also got it inverted on some devices.

OZApps · December 2013

@Aditya, as tkhoman said, different android devices handle this differently, I recollect the Huawei Tablet about 2/3 years ago was inverted and the same code on another android phone worked fine. Where as it is all standard for all iOS devices.

ar2rsawseen · December 2013

Hello @aditya

which device it is exactly?

I know some device's accelerometer behavior depends on the orientation, while most of them use absolute values.

I think that is mostly the reason why games implement sensor calibration, to understand how this specific device behaves and then adjust accordingly.

Currently I don't know any programmatical way to detect the different behavior

alexzheng · December 2013

is this the same bug I reported long ago?

http://www.giderosmobile.com/forum/discussion/2559/accelerometer-values-in-upside-down#Item_8

aditya · December 2013

@OZApps: Thats a bit scary...:P

@ar2rsawseen: Nexus 7 tablet. The orientation has been set as 'landscape_left' in gideros and 'landscape' in androidmanifest.

The problem as others have mentioned above, is that I don't really have a list of devices which invert the axes to compare and check with.

aditya · December 2013

@alexzheng: By inverted, I mean my character moves horizontally when i tilt the device vertically and vice versa.

OZApps · December 2013

@Aditya, what I faced was like the true scroll on OSX since Lion, where if I tilted the device downwards, the ball (or rather the ball bearing in Labyrinth) moved upwards and the other way around. This is one of the main reasons why development with an iOS device is a pleasure. However people/users (in India) still love their Androids.

aditya · December 2013

@OZApps: Agreed, iOS is nice. But people everywhere love their androids (including me...:D) isn't it? The age old device fragmentation debate.

Would we happen to have a fix for this problem in gideros?

ar2rsawseen · December 2013

@aditya by calibration I meant give users instructions, like
1) put device on the flat surface in landscape mode
2) record the accelerometer readings
3) ask user to put device on the flat surface in portrait mode
4) record readings
5) decide based on values how to use accelerometer
6) store these settings for every use later

aditya · December 2013

Understood. But that sounds like a lot of work for the end user. Is there any another way to make it easier?

OZApps · December 2013

@Aditya, you would never know if the accelerometer is inverted or not. However you can have a switch in the UI, something like the true scroll that could allow the user to invert the accelerometer, which means you either swap or invert the values received.

something like

if accel_inverted == true then
  x = -x
else
  -- Do nothing here
end

ar2rsawseen · December 2013

Yes as @OZApps said, there also could simply be a switch in the settings, and you could notify user during a loading screen, if you experience problems with accelerometer, try switching axis (or calibration)

aditya · December 2013

Yes, currently we are doing this:
if (application:getDeviceInfo()=="Android") then
--Android Movement
else
--iOS Movement
end

Not the best way after reading comments on this thread. You are right I would have to add it as an option in the 'Settings' screen as a last resort.

petec · December 2013

I also came across this problem in a game I was playing where you had to roll a ball through a labyrinth to progress in the game. Having struggled (and failed!)for ages trying to make myself do the opposite of what was natural, cursing the developoer for making it so difficult, I decided to turn my tablet upside down which fixed it.

That game allowed autorotate of the screen. Is that not possible on Android? I know that the settings are either landscape left or landscape right so I'm guessing there is some reason why Gideros won't autorotate?

aditya · December 2013

Saw the thread by @alexzheng.

Would second application:getOrientation() giving out the active orientation of the device.

ar2rsawseen · December 2013

@aditya no only the one set in the project properties, but as far as I know, the orientation change events are coming in the

atilim · December 2013

A new function Application:getDeviceOrientation is coming with the next version. So that you can fix the accelerometer data with a simple code without checking the OS.

aditya · December 2013

Best news all day. When would the next version be coming out?

atilim · December 2013

really soon

alexzheng · December 2013

A new function Application:getDeviceOrientation is coming with the next version. So that you can fix the accelerometer data with a simple code without checking the OS.

will the orientation change events also be coming?

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