How to interpret Acceleration X, Y, Z values for ABSensor N01

I am testing NRF52810 ABSensor N01 to get Acceleration X, Y, Z. Those data can be read by scanning broadcasting by using your app asensor-android-demo with minor code changes. Here is results in hex “020106030359FE171659FEAB01038420201489E9620000FDFDC300056400000D0961626561636F6E5F323038340000000000000000000000000000000000”
According to user document Acceleration X, Y, Z values are read from byte [23], [24], [25]. When beacon is put on a table and faceup. Those X, Y, Z values are 254, 253, 197. The values are changing while beacon is turning or moving. Here is three questions:

  1. How to interpret those value? Should a unsigned or signed value be used?
  2. Why are there values (not equal to zero) even no Acceleration or no movement?
  3. What is units for those values?

Thanks in advance.


Did you change the beacon to sensor mode first? You can use our iOS app AprilBeacon to do the job.

See the wiki for the packet format.

The x, y, z values are signed value. The unit is g.

Thanks for your quick response. I did change it to Sensor mode when I tested them. Acceleration X, Y, Z values are -3, 0, -60 as signed respectively when beacon is on a table and face-up in static. How those values are explained especially for -60 of acceleration Z? Do you have more document about acceleration sensor?

Please check the datasheet of acceleration sensor LIS3DH. Is it helpful?