I have recently acquired a 3-axis digital gyroscope (based on the ITG3200) but I don't understand what represent the values it returns..

[Anonymous]

Hi,
I have recently acquired a 3-axis digital gyroscope (based on the ITG3200) but I don't understand what represent the values it returns...

What represent the X,Y and Z values ? Are they angle (in radian ?) or position (in mm ?) ?
Also, are the value provided the final value (angle/position and angular velocity) or are they raw data that i need to convert ? If yes can you provide information about the conversion process ?

Thank you in advance

[Seeed Tech Support]

Hi there~

1. X/Y/Z: A gyroscope itself is generally an analog device in the sense that in reality, it will have a continous output. This output is digitized using some form of Analog to Digital A/D converter where the analog output is converted to a digital number.

2. The function getAngularVelocity will get the degree / second reading. 

/*Function: Get the angular velocity and its unit is degree per second.*/
void ITG3200::getAngularVelocity(float *ax,float *ay,float *az)
{
  int16_t x,y,z;
  getXYZ(&x,&y,&z);
  *ax = x/14.375;
  *ay = y/14.375;
  *az = z/14.375;
}

https://github.com/Seeed-Studio/Grove_3_Axis_Digital_Gyro/blob/master/ITG3200.cpp#L110  

3. You can get more reading about gyro. 

https://arduino.stackexchange.com/questions/14474/what-does-lsb-per-degree-per-second-mean 

Thanks

best rgds
Bill

[Anonymous]

Hi Bill,

thanks for your quick answer, I found right after I sent the mail.

There is still one thing I don't get, is the speed really in degrees/s (or is it in radian/s) ? I can't see any conversion between radian and degrees, more over on this page of your site ( http://wiki.seeedstudio.com/Grove-3-Axi ... ro/website), it tells the speed is in radian/s.

Thank you

[Seeed Tech Support]

Hi Vincent,

It is degrees per second.  

Thanks

best rgds
Bill