[Gta04-owner] Making sense of the sensors.

Benjamin Deering ben_deering at swissmail.org
Thu Aug 9 23:13:13 CEST 2012


It is going crazy.  I watched the 3 axis in sensmon.  X and Y are 
reasonable if I adjust the range, but Z sends random looking garbage.  
Even moving a powerful magnet close around the phone makes no noticeable 
change.

On 08/09/2012 05:07 PM, Michele Brocco wrote:
> Is the needle going crazy or is it constantly showing in the same
> direction if you don't move your device?
>
>
> On 8/9/12, Benjamin Deering<ben_deering at swissmail.org>  wrote:
>> I played a bit with valacompass on GTA04.  Libsensmon would need a
>> BMA150 module for tilt compensation to work, but I commented out the
>> accelerometer code in my build.
>>
>> The hmc5843 driver for the latest SHR kernel has the sysfs files in a
>> different place.
>>
>> I changed .Sensmon/config to include:
>> [Hmc5843Source]
>> device=/sys/bus/i2c/devices/2-001e/iio:device0
>>
>> The sysfs file 'rate' seems to have changed to sampling_frequency.
>>
>> X,Y,and Z values come from separate files.  I'm not a vala programmer,
>> but I can send what I did to get them.
>>
>> I had to adjust in_magn_range to get the Y axis to show anything but
>> -4096.0
>>
>> I don't know how important the tilt compensation is, but with all my
>> changes the needle in valacompass does not point north.  The direction
>> it points seems to change when I rotate the phone, but it is very
>> noisy.  I think there is some interference from the speaker magnets as I
>> was able to get a reading on the Y axis without adjusting the range if I
>> brought a magnet near the phone.  I have Slyon's 3d printed speaker box
>> and 2 speakers, maybe those with a single speaker will have different
>> results.
>>
>> Ben
>>
>> On 08/04/2012 02:10 PM, Michele Brocco wrote:
>>> On 8/4/12, NeilBrown<neilb at suse.de>   wrote:
>>>> The compass seems to have a strong bias on all axes. Presumably some
>>>> magnet
>>>> in the GTA04 (speaker?) needs to be compensated for.  Has anyone played
>>>> with
>>>> this at all?  Figured out how to calibrate, then how to convert the 3
>>>> numbers
>>>> into  a compass direction?
>>> hi neil,
>>>
>>> I wrote a proof of concept user space compass application for the
>>> navigation board (http://wiki.openmoko.org/wiki/ValaCompass). you can
>>> take a look at the source code if you want. i wanted to update the
>>> application once the kernel in shr will support this sensor and the
>>> accelerometers. but currently I am very busy and could not chek if
>>> everything is there already.
>>>
>>> regards,
>>>
>>> Michele
>>> _______________________________________________
>>> Gta04-owner mailing list
>>> Gta04-owner at goldelico.com
>>> http://lists.goldelico.com/mailman/listinfo/gta04-owner
>>>
>> _______________________________________________
>> Gta04-owner mailing list
>> Gta04-owner at goldelico.com
>> http://lists.goldelico.com/mailman/listinfo/gta04-owner
>>
> _______________________________________________
> Gta04-owner mailing list
> Gta04-owner at goldelico.com
> http://lists.goldelico.com/mailman/listinfo/gta04-owner
>



More information about the Gta04-owner mailing list