touch-packages team mailing list archive

[Michał Sawicz <michal.sawicz@xxxxxxxxxxxxx>]

** Changed in: canonical-devices-system-image
     Assignee: (unassigned) => John McAleely (john.mcaleely)

** No longer affects: unity8 (Ubuntu)

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https://bugs.launchpad.net/bugs/1529592

Title:
  Accelerometer has an offset

Status in Canonical System Image:
  New

Bug description:
  Summary:
  The accelerometer data is in detail not correct. This is either a specific hardware bug of my phone, the Aquaris 4.5 or all Aquaris phones or this is a software bug in reading the accelerometer data of the sensor.

  This might also be a root cause of bug:
  https://bugs.launchpad.net/ubuntu/+source/unity8/+bug/1474225

  My phone:

  current build number: 28
  device name: krillin
  channel: ubuntu-touch/stable/bq-aquaris.en
  last update: 2015-12-16 12:25:08
  version version: 28
  version ubuntu: 20151210
  version tag: OTA-8.5
  version device: 20150821-736d127
  version custom: 20151111--36-46-vivid

  Task 1: 
  I have attached a screenshot of the app "Level". I have placed the phone on a surface which is leveled quite well. 
  Expectation 1: 
  The app level shows that the surface is leveled and the red dot is in the middle. 
  Result 1: 
  The red dot shows an offset of about 0.5 - 1 degree to "bottom left". This might be caused by a not fully leveled surface. 

  
  Task 2: 
  I have turned the phone by 90°
  Expectation 2: 
  The red dot moves by 90° in the direction I turn the phone.
  Result 2: 
  The red dot stays in exactly the same position (in relation to the orientation of the phone): bottom left. This means that a second screen shot would show exactly the same picture eventhough I have turned the phone by 90°.

  Task 3:
  I used "Sensor Status" - Accelerometer and I made 5 screen shots where I placed the phone on the same leveled surface and rotated the phone to 0°, 90°, 180°, 270°, 360°. 
  Expectation3:
  The calculation of the angles of the 5 screen shots should give 4 different angles differing each by approx. 90°.
  Result3:

  Results of the „Sensor Status“ Accelerometer of the BQ Aquaris 4.5 lying on a flat surface					
  					
  angle of the phone		x	y		calculated angle
  0		-0,421	-0,277		-146,66
  					
  90		-0,43	-0,335		-142,08
  					
  180		-0,43	-0,316		-143,69
  					
  270		-0,44	-0,306		-145,18
  					
  0		-0,44	-0,296		-146,07

  I have also attached the 5 screen shots and the Calc file with the
  background how I came to these results.

  This clearly shows that the accelerometer has an offset. This is
  either a specific hardware bug of my phone, the Aquaris 4.5 or all
  Aquaris phones or this is a software bug in reading the accelerometer
  data of the sensor.

  Uranicus

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