[Gta04-owner] Second trial with QtMoko2

[Sven Dyroff]

Hello Nikolaus,

have you tried if GTA04A5 now moves the ball in QtMaze as smooth, fast and 
natural and without stuttering as the GTA04A4?

Best regards
   Sven
 




Von:    "H. Nikolaus Schaller" <hns at goldelico.com>
An:     List for communicating with real GTA04 owners 
<gta04-owner at goldelico.com>
Datum:  12.04.2018 14:52
Betreff:        Re: [Gta04-owner] Second trial with QtMoko2
Gesendet von:   "Gta04-owner" <gta04-owner-bounces at goldelico.com>



Am 12.04.2018 um 14:32 schrieb Sven Dyroff <S.Dyroff at phytec.de>:

Hello Nikolaus, 

it would astonish me if you're right, but of course I'll then test it 
again in order to give you a chance to astonish me...    :-)) 

I have done this test for you:

GTA04A4 and GTA04A5 with display upside on the table with the same µSD 
card (i.e. boot A5 first, then swap card and boot A4).
Run evtest /dev/input/accel | head -20 and write down highest X/Y/Z 
values.

On a GTA04A5:

root at letux:~# evtest /dev/input/accel | head -20
Input driver version is 1.0.1
Input device ID: bus 0x0 vendor 0x0 product 0x0 version 0x0
Input device name: "accelerometer-iio-input-bridge"
Supported events:
  Event type 0 (EV_SYN)
  Event type 3 (EV_ABS)
    Event code 0 (ABS_X)
      Value     14
      Min     -511
      Max      511
    Event code 1 (ABS_Y)
      Value    -32
      Min     -511
      Max      511
    Event code 2 (ABS_Z)
      Value   -253
      Min     -511
      Max      511
Properties:
Testing ... (interrupt to exit)
root at letux:~# 

This means: X=14/256 = +5%, Y=--32/256 = -12%, Z=-253/256 = -99%

On a GTA04A4:

root at letux:~# evtest /dev/input/accel | head -20
Input driver version is 1.0.1
Input device ID: bus 0x0 vendor 0x0 product 0x0 version 0x0
Input device name: "accelerometer-iio-input-bridge"
Supported events:
  Event type 0 (EV_SYN)
  Event type 3 (EV_ABS)
    Event code 0 (ABS_X)
      Value    -15
      Min     -511
      Max      511
    Event code 1 (ABS_Y)
      Value     -5
      Min     -511
      Max      511
    Event code 2 (ABS_Z)
      Value    274
      Min     -511
      Max      511
Properties:
Testing ... (interrupt to exit)
root at letux:~# 

This means: X=-15/256 = +6%, Y=--5/256 = -2%, Z=274/256 = +107%

Comparing A4 and A5: they basically behave *the same* regarding the range
and report both +/-256 for 1g. They just differ in the orientation of the 
sensor.

I.e. the Z axis also has a sign error. This is still missing in my 
correction patch.
To make it really precise I should rotate both devices by 90° and write 
down all
values...

What I don't know and can't compare is if they behave like a GTA02... And
if a total value of ~1g is what QtMaze expects. And if the QtMaze makes 
use
of the Z-axis at all (doesn't look as if it does).

BR,
Nikolaus



Best regards
   Sven 
     




Von:        "H. Nikolaus Schaller" <hns at goldelico.com> 
An:        List for communicating with real GTA04 owners <
gta04-owner at goldelico.com> 
Datum:        12.04.2018 14:25 
Betreff:        Re: [Gta04-owner] Second trial with QtMoko2 
Gesendet von:        "Gta04-owner" <gta04-owner-bounces at goldelico.com> 




Hi Sven, 

Am 12.04.2018 um 14:19 schrieb Sven Dyroff <S.Dyroff at phytec.de>: 

Hello Nikolaus, 

fine, but this will "only" correct the swapping. It will still not correct 
the calibration. 

Whereat the comments of the affected source give a nice hint: "On my 
GTA04, sitting flat on the table, the raw Z acceleration value is about 
256, so we divide by 256 here." 

So I suggest to add a further printf of the value of "accel -> z", in 
order that your code will provide you the needed calibration data that you 
can then use for "accel -> [xyz]scale" in case of having detected a 
GTA04A5. 

It is easier than a printf: evtest /dev/input/accel reports the range 
[0..512] and the current values. 

I have checked that and the GTA04A5 also reports roughly 256. 

So I think you should test (after I have uploaded it to the server) if it 
is now ok for you. 

BR, 
Nikolaus 


Best regards 
  Sven 
   




Von:        "H. Nikolaus Schaller" <hns at goldelico.com> 
An:        Sven Dyroff <S.Dyroff at phytec.de> 
Kopie:        List for communicating with real GTA04 owners <
gta04-owner at goldelico.com> 
Datum:        11.04.2018 19:21 
Betreff:        Re: [Gta04-owner] Second trial with QtMoko2 
 



Hi Sven, 

Am 05.04.2018 um 18:05 schrieb Sven Dyroff <S.Dyroff at phytec.de>: 

Hello Nikolaus, 

> I have now booted my GTA04A4 and the orientation is completely correct.
> Hm. Maybe a subtle difference between GTA04A4 and A5? They use different 
accelerometer chips. 

something like that is what I already assumed. Would have wondered me if 
some scaling factors would have gone lost by just rebuilding QtMoko...

I have now added a device version detection to swap the horizontal axis if 
we run on a GTA04A5: 

http://git.goldelico.com/?p=gta04-qtmoko.git;a=commit;h=04c30a3b18be8b55148427d6c63423837f6a77cc 


I have not yet published the new debian packages, but will do soon. So 
apt-get update will not 
yet find anything new. 

BR, 
Nikolaus 
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