[Miscellaneous Android Development] KY69:
Inverted z-axis on magnetic sensor

Hi, I just finished reading the whole thread, post by post. I also followed links to other threads and fora, and searched the internet as a whole nonstop for days, but was not able to find any mention to the following problem.

I received my W100 a few days ago, it came with the 130802 firmware. Everything seems to be working except for the z-axis of the magnetic sensor. When using astronomy software (e.g. Mobile Observatory, SkEye, Google Sky Map), if I move to the right, the W100 acts as if I moved to the left, and vice versa. This led me to investigate the output of the related sensors (tried a few apps, AndroSensor was most informative), and everything looks normal, including magnetic readings for the x and y axes (first suspects), except for the z-axis of the magnetic sensor, which gives me the expected module but with the inverted signal, i.e., it gives me positive numbers when they should be negative, and vice versa.

The output of the accelerometer is coherent on x, y, and z. After analysing the AndroSensor output from another phone that also has a magnetic sensor (Motorola Atrix TV XT687, where I use the above mentioned programs without a problem) I concluded that both accelerometer and magnetic sensors use right-hand coordinate systems. On the XT687 everything is as expected.

On the W100, though, the magnetic sensor is using a left-hand coordinate system, even though it uses a right-hand coordinate system for the accelerometer. This explains why the W100 has an "inverted" world.

My questions are:

1) has anyone noticed this?

2) In your opinion, is it more probable of this being a hardware or a software problem?

3) Does anybody know how to fix this?

My thoughts on:

- Q1: I can't believe I'm the only one in the whole world with a "winning ticket" :(

- Q2: a software problem would mean everyone with the same software version would have to have the same problem. That should add to quite a lot of people already. A hardware problem could mean either a whole lot more or a whole lot less units with the same problem, but again, I find it hard to believe I am the only one in the world...

- Q3: the one that really matters. Is there a way to fix this or will I have to send the phone back?

Thanks for any suggestions, no matter how wild they may be!

PS: in case anyone is willing enough, SkEye and Google Sky Map are both free and can be downloaded from the market.

2013/09/12:

PS2: would anybody be kind enough to make a few tests on their W100? AndroSensor, SkEye and Google Sky Map are all free and can be installed directly from the market. I need to establish if I have a hardware problem or a software problem. If I have a software problem I will keep the phone and struggle to fix it, but if I have a hardware problem I need to return the phone, and I am running out of time. I would really appreciate if someone could spend a few minutes and help me out on this issue.

Simple tests:

- On AndroSensor's magnetic field, with the phone lying on a table and facing up, regardless of the values for x and y, is z positive or negative? It has to be positive, but my W100 reads negative. If holding the W100 so that the screen faces the ground, is the value for z positive or negative? It has to be negative, but my W100 reads positive.

- On either SkEye or Google Sky Map, if you move to the right or to the left, does the sky update accordingly or is it reversed (i.e. you move to one side but the phone responds as if you moved to the other, like mine)?

These should take only a few minutes, but just the AndroSensor test is already enough information for me, and that should take about a minute including downloading, installing the app, and doing the test. Thank you very much for anyone who is kind enough to give me a hand.