Need help interpreting MinIMU-9 readings

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1

Hi all,

I have the MinIMU-9 product shown here:

https://www.pololu.com/catalog/product/1265

I have the sample AHRS application working with the Arduino and have made some changes to the program. To send data back to the host I am using the following lines:

 Serial.print(ToDeg(roll));
 Serial.print(",");
 Serial.print(ToDeg(pitch));
 Serial.print(",");
 Serial.println(ToDeg(yaw));

 Serial.println(MAG_Heading);

The magnetic heading, for example, is a number between -3 and +3, but I don’t understand how the number represents the four coordinates (North, South, East, West). Same problem with the roll, pitch and yaw. I am not sure what the numbers represent. Is there somewhere where this is documented and I can read about it?

Or if any one knows this off hand, perhaps a quick recap? I don’t mind doing my homework, but I can’t seem to find any information on how to interpret this data. I had a look at the Python sample source, but frankly I was not able to understand how the data from the Arduino is used. Thank you! Salvador

2

Hi, Salvador.

The estimated yaw, pitch, and roll angles that are calculated by the AHRS program are angles of rotations (in degrees) in three dimensions. You can read more about yaw, pitch, and roll angles here.

As for magnetic heading, the MAG_Heading output should be in radians, where a 0 radian reading would correspond to North.

- Zeeshan

3

Thanks Zeeshan, I am looking at the information in the links that you provided. Best, Salvador