Erroneous Arduino values

[Honest-Objections]

While I may just be misunderstanding entirely, I would expect the Arduino code to spit out degrees between 0-360. When running on the GPS-IMU V2 I get:

#AccX   0.96    ###  AccY  -88.85  ###  GyrX    41642.30  ###  GyrY     2140885.00   ###  GyrZ  44169.29     ######    CFangleX 3.62   ######  CFangleY     2874.74   ######  heading       2.94    --Loop Time--   20
#AccX   0.70    ###  AccY  -88.86  ###  GyrX    41642.38  ###  GyrY     2140976.75   ###  GyrZ  44169.33     ######    CFangleX 3.62   ######  CFangleY     2874.74   ######  heading       2.75    --Loop Time--   20
#AccX   1.01    ###  AccY  -88.86  ###  GyrX    41642.47  ###  GyrY     2141068.50   ###  GyrZ  44169.37     ######    CFangleX 3.62   ######  CFangleY     2874.73   ######  heading       2.53    --Loop Time--   20
#AccX   0.75    ###  AccY  -88.86  ###  GyrX    41642.56  ###  GyrY     2141160.25   ###  GyrZ  44169.42     ######    CFangleX 3.62   ######  CFangleY     2874.73   ######  heading       2.54    --Loop Time--   20
#AccX   0.78    ###  AccY  -88.84  ###  GyrX    41642.64  ###  GyrY     2141252.00   ###  GyrZ  44169.46     ######    CFangleX 3.61   ######  CFangleY     2874.72   ######  heading       2.57    --Loop Time--   20
#AccX   0.78    ###  AccY  -88.85  ###  GyrX    41642.72  ###  GyrY     2141343.75   ###  GyrZ  44169.50     ######    CFangleX 3.61   ######  CFangleY     2874.72   ######  heading       2.54    --Loop Time--   20
#AccX   0.79    ###  AccY  -88.86  ###  GyrX    41642.81  ###  GyrY     2141435.50   ###  GyrZ  44169.55     ######    CFangleX 3.61   ######  CFangleY     2874.72   ######  heading       3.06    --Loop Time--   20

So the heading seems fine, I don't know what's going on with the rest of it.

[vbahtev]

Any solution ?

[vbahtev]

After hard iron calibration code work perfectly.

Before use values from heading, first make 360 degree horizontal rotation.

In gits can see: arduino-BerryIMU code with hard iron calibration.

https://gist.github.com/vbahtev/b05f1895776cec5828db6746d5ba9a11

[Honest-Objections]

In my case it turned out to be bit shifting with assumption that the Arduino would be 16bit where as the zero was 32bit (from what I remember). Never got it working though, thanks for sharing the code!

[aaron9412]

I've gotten similar results. Like @Honest-Objections stated I believe it is a calculation error, solutions may be unique depending on the board. Please let us know what board this was designed using, and if there are any known solutions. I will be trying to correct it for an SAMD (ItsyBitsy M0 Express). Thank you for the nice library. -Aaron

> 21:33:40.650 -> #AccX 88.83   ###  AccY  -88.83  ###  GyrX    1183149.00  ###  GyrY   1168714.50   ###  GyrZ  1184804.12     ######    CFangleX   3053.96   ######  CFangleY      2877.29   ######  heading       73.58    --Loop Time--  20
> 21:33:40.697 -> #AccX 88.83   ###  AccY  -88.83  ###  GyrX    1183240.75  ###  GyrY   1168806.25   ###  GyrZ  1184895.87     ######    CFangleX   3053.97   ######  CFangleY      2877.28   ######  heading       73.36    --Loop Time--  20
> 21:33:40.697 -> #AccX 88.83   ###  AccY  -88.83  ###  GyrX    1183332.50  ###  GyrY   1168898.00   ###  GyrZ  1184987.62     ######    CFangleX   3053.97   ######  CFangleY      2877.29   ######  heading       73.23    --Loop Time--  20
> 21:33:40.744 -> #AccX 88.82   ###  AccY  -88.82  ###  GyrX    1183424.25  ###  GyrY   1168989.75   ###  GyrZ  1185079.37     ######    CFangleX   3053.97   ######  CFangleY      2877.29   ######  heading       73.98    --Loop Time--  20
> 21:33:40.744 -> #AccX 88.83   ###  AccY  -88.83  ###  GyrX    1183516.00  ###  GyrY   1169081.50   ###  GyrZ  1185171.12     ######    CFangleX   3053.98   ######  CFangleY      2877.29   ######  heading       73.56    --Loop Time--  20
> 21:33:40.744 -> #AccX 88.83   ###  AccY  -88.83  ###  GyrX    1183607.75  ###  GyrY   1169173.25   ###  GyrZ  1185262.87     ######    CFangleX   3053.97   ######  CFangleY      2877.29   ######  heading       73.50    --Loop Time--  20
> 21:33:40.791 -> #AccX 88.83   ###  AccY  -88.83  ###  GyrX    1183699.50  ###  GyrY   1169265.00   ###  GyrZ  1185354.62     ######    CFangleX   3053.98   ######  CFangleY      2877.29   ######  heading       73.16    --Loop Time--  20
> 21:33:40.791 -> #AccX 88.82   ###  AccY  -88.82  ###  GyrX    1183791.25  ###  GyrY   1169356.75   ###  GyrZ  1185446.37     ######    CFangleX   3053.97   ######  CFangleY      2877.29   ######  heading       73.10    --Loop Time--  20
> 21:33:40.838 -> #AccX 88.83   ###  AccY  -88.83  ###  GyrX    1183883.00  ###  GyrY   1169448.50   ###  GyrZ  1185538.12     ######    CFangleX   3053.98   ######  CFangleY      2877.30   ######  heading       73.09    --Loop Time--  20
> 21:33:40.838 -> #AccX 88.83   ###  AccY  -88.83  ###  GyrX    1183974.75  ###  GyrY   1169540.25   ###  GyrZ  1185629.87     ######    CFangleX   3053.98   ######  CFangleY      2877.30   ######  heading       73.95    --Loop Time--  20
> 21:33:40.885 -> #AccX 88.82   ###  AccY  -88.82  ###  GyrX    1184066.50  ###  GyrY   1169632.00   ###  GyrZ  1185721.62     ######    CFangleX   3053.97   ######  CFangleY      2877.29   ######  heading       73.20    --Loop Time--  20
> 21:33:40.885 -> #AccX 88.83   ###  AccY  -88.83  ###  GyrX    1184158.25  ###  GyrY   1169723.75   ###  GyrZ  1185813.37     ######    CFangleX   3053.97   ######  CFangleY      2877.30   ######  heading       73.51    --Loop Time--  20
> 21:33:40.885 -> #AccX 88.82   ###  AccY  -88.83  ###  GyrX    1184250.00  ###  GyrY   1169815.50   ###  GyrZ  1185905.12     ######    CFangleX   3053.96   ######  CFangleY      2877.29   ######  heading       73.36    --Loop Time--  20

[aaron9412]

The issue is that 32 bit processors create 32 bit signed integers when "int" is called. The LMD9DS sensors are set up to output information into 16 bit signed integers, which the author has exemplified for us well:

3) The values are expressed in 2’s complement (MSB for the sign and then 15 bits for the value) so we need to combine; block[0] & block[1] for X axis block[2] & block[3] for Y axis block[4] & block[5] for Z axis

Quoted from: http://ozzmaker.com/compass1/

The Arduino example code should work nicely with no modifications on a 16 bit processor and 16 bit Arduino. For a 32 bit or other processor, simply change all the "int" calls to "int16_t" and the issue will be solved. (Do not use "uint16_t" as this is unsigned, eg: cannot be negative). "int" calls and "int16_t" calls both natively use 2's compliment to store their numbers, so conversion to decimal is not necessary.

-Aaron