Accelerometer data format API

Sleep as Android Q&A
1

Hi. May I know, in what format does SleepAsAndroid expect to get data from com.urbandroid.sleep.watch.DATA_UPDATE intent?

Send movement data
Intent : com.urbandroid.sleep.watch.DATA_UPDATE
Extras:
MAX_DATA (float array): Array containing latest MAX values from the watch.
MAX_RAW_DATA (float array): Array containing a geometric average of latest MAX values from the watch.

This sentence from documentation is a bit confused:

The values to be aggregated should be changes in raw accelerometer data expressed in m/s2.

Do both MAX_DATA (float array) and MAX_RAW_DATA (float array) and x/y/z from pseudocode have to be in m/s?

  on_sensor_change() {
  
  x = sensor.x;
  y = sensor.y;
  z = sensor.z;

  max = abs(x - lastX) + abs(y - lastY) + abs(z - lastZ);
  if (max > current_max_data) {
    current_max_data = max;
  }

  max_raw = sqrt((x * x) + (y * y) + (z * z));
  if (max_raw > current_max_raw_data) {
    current_max_raw_data = max_raw;
  }

  lastX = x;
  lastY = y;
  lastZ = z;
}
2

According to Garmin Addon source code:
MAX_DATA has to be in milli-G-units (G * 1000)
MAX_RAW_DATA has to be in m/s2

Am I right?

3

Yes, your assumptions are correct.
However the max_data is actually legacy api - it will suffice to send only max_raw_data. Sleep supports both but prefers the raw format when receiving both.

1 Like
4

Looks like Accelerometer API documentation lacks some information.
I see Sleep-as-Android-GearSx-Addon send additional extra data to SleepAsAndroid app like:

  1. MIN_DATA
  2. AVG_DATA

May I know the purpose of this and how it affects sleep report?

5

Those are unused. They are leftovers in the addon from early versions of Sleep. We should get rid of them.

1 Like