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CC2650 accelerometer data problem

Hello, 

I'm developping my own app in c# and I take inspiration from this code 

git.ti.com/.../sensortag

The problem is for the accelerometer data, It's by default configure at 2G, so I have this : 

float aX = (((data[7]<<8) + data[6]) / 16384.0f);

float aY = (((data[9]<<8) + data[8])/ 16384.0f);

float aZ = (((data[11]<<8) + data[10])/ 16384.0f);

The data are aroung 4 for all the axis and not 0, that's the first issue, but the big problem is that the data jump to 0 and go up to 0.300 when I move the accelerometer to the right, and back to 4 and go down to 3.600 when moving it to the left for example.

On the android official app to data are around 0 et go to 1 and -1 

If someone have a solution, that would be great ! :)

Thank you for reading

  • Hello Sami,

    You can control & configure the MPU-9250 via the associated movement service. Please see the SensorTag User's Guide, which is available from the TI BLE Wiki: www.ti.com/ble-wiki.

    I also recommend searching E2E as there have been other topics on the accelerometer.

    Best wishes
  • Hi, 

    Yes with the AA80 for the movement service, but the data is not calibrate around 0, do I have to do it with code, or it have a way to configure the accelerometer ?

    And how can I change the range (2G by default), I tried this : byte[] enableSensor = new byte[]{0x38,0x02}; where I set which data I want (here just the accelerometer 0x38 from the movement service) and the range, but it doesn't work for the range, I can't change it.

    Thank you for your answers :)

  • I would also like to know if you have found how to switch sensitivity in BLE stack 2.1, did you get a response or solved it in some way, or does your problem still exist?

    Would be great if anyone have some input on this matter, as the method to change Accelerometer sensitivity seems to have been changed between BLE 2.0 and 2.1 without being documented (where I can find it).

  • Hello, 

    No I didn't find how to set the sensitivity, it's still at 2G, but the other problem is the data itself.

    It's not calibrate around zero, but worst, the data jump from 0 to 4 for the accelerometer, to 500 for the gyro. And I don't know if it have a way to calibrate it without do it myself in code.

    So if someone get clean data from the mouvement sensor, I'm highly interested ! :)

    Thanks,