3-axis accelerometer frame of reference?

#1

Hi,

I am really enjoying the amazing new functionality offered by the Estimote LTE Beacons.

I have been asked to run a test on the new beacons which requires knowing the frame of reference, or local coordinate system for the 3-axis accelerometer on the beacon. Once I know the LCS I will use 2 beacons together to test the precision of the accelerometers. By holding the first sensor in a fixed position and then varying the second to an orthogonal orientation certain physics calculations can be done.N.B. I believe the Apple iPhones work in a similar manner, combining a Bosch and Intellisense (sp?) combination.

Also, can you specify what type of accelerometer is used so that I can include this information in my study?

thank you for any tips,

Cheers.

#3

I wrote a simple micro-app:

timers.repeat(1000, () => {
  var accel = sensors.accel.get();
  print(accel.x.toFixed(4) + ", " + accel.y.toFixed(4) + ", " + accel.z.toFixed(4));
});

… and experimented a bit to see where the gravity vector shows up, and based on that, I came up with this coordinate system:

tumblr_inline_pqep2mSDOw1ui1qvq_540

Also, can you specify what type of accelerometer is used so that I can include this information in my study?

We generally don’t share what exact components go into our beacons.