[TIMOB-564] Accuracy of compass and accelerometer

GitHub Issue	n/a
Type	Bug
Priority	Medium
Status	Closed
Resolution	Fixed
Resolution Date	2011-07-27T16:56:36.000+0000
Affected Version/s	n/a
Fix Version/s	n/a
Components	iOS
Labels	accelerometer, ios, iphone
Reporter	flaz83
Assignee	Reggie Seagraves
Created	2011-04-15T02:32:04.000+0000
Updated	2011-07-27T16:56:36.000+0000

Description

Hi, I'm working on augmented reality, so I need to use accelerometer and compass features.
The problem is the measurement accuracy. The measurement difference of the accelerometer with a little movement of the iPhone it's about 2-3%, while in other application like AroundMe or iHandyLevel it seems to be more accurate. Is it possible to change/increase the accuracy on iPhone? Thanks a lot, Flavio

Comments

flaz83 2011-04-15
I have found a solution.
If you need more accuracy, you can do as apple suggests:

var accelX = 0;
var accelY = 0;
var accelZ = 0;
var kFilteringFactor = 0.1;

Ti.Accelerometer.addEventListener('update',function(e)
{
```
   accelX = (e.x * kFilteringFactor) + (accelX * (1.0 - kFilteringFactor));
   accelY = (e.y * kFilteringFactor) + (accelY * (1.0 - kFilteringFactor));
   accelZ = (e.z * kFilteringFactor) + (accelZ * (1.0 - kFilteringFactor));
   
   ts.text = e.timestamp;
   x.text = 'x: ' + accelX;
   y.text = 'y:' + accelY;
   z.text = 'z:' + accelZ;
   
```
});

This uses a low-value filtering factor to generate a value that uses 10 percent of the unfiltered acceleration data and 90 percent of the previously filtered value.
-> More accuracy but short-lived changes in motion.

Regards, Flavio
Vikramjeet Singh 2011-07-27 Bug: Invalid. Apple don't support this. Not possible. Asked Blaine

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