You’ve downloaded the CSV data file for your record or activity and you’re wondering what each column stands for (for more details, please also refer to the API documentation):
1st column: Timestamp (s/256)
Hexoskin samples some of its data at 256Hz so timestamps found in the CSV file are in 256ths of a second (i.e. time [s/256]).
If you want a regular Unix epoch time format (number of seconds that have elapsed since January 1st, 1970 at 00:00:00 GMT), simply divide the value in the first column by 256. In the example above, the 3 first lines read:
A2 = 390747224745, divide by 256 --> 390747224745/256 = 1526356347
A3 = 390747225001, divide by 256 --> 390747225001/256 = 1526356348
A4 = 390747225257, divide by 256 --> 390747225257/256 = 1526356349
Then, if you want to convert it in normal time, please use the resulting number into an epoch & unix converter.
A2 = 390747224745/256 = 1526356347, convert --> Tuesday, May 15, 2018 3:52:27 AM
A3 = 390747225001/256 = 1526356348, convert --> Tuesday, May 15, 2018 3:52:28 AM
A4 = 390747225257/256 = 1526356349, convert --> Tuesday, May 15, 2018 3:52:29 AM
Each line represents a second in time.
2nd column: Breathing Rate (respirations/minute, rpm)
This is the number of breaths per minute, calculated as the average breathing rate of the last 7 breaths.
3rd column: Minute Ventilation (ml/minute, mL/min)
This is the volume (in mL) of breathed air per minute, calculated for the last 7 complete respiration cycles.
4th column: Sleep position
This is the user's sleep position during a sleep activity. Sleep positions detected are belly, back, right, left and standing.
5th column: Activity (g)
Basically, we get a square root of the sum of the square of each of the accelerometer components.
6th column: Heart Rate (beats/minute, bpm)
This is the heart rate in beats per minute, calculated as the average of the last 16 heartbeats.
7th column: Cadence (steps/minute, spm)
This is the number of steps per minute, calculated as the average of the last 7 strides.