11-11-2018, 11:02 AM
The time logged by phyphox (which is the time in your exported data and the one in the buffers you can request via JSON) is based on the time of the sensor event as given by the system (for example on Android: https://developer.android.com/reference/...ensorEvent). This is (nominally) given in nanoseconds uptime (since the system started), so in principle it is quite precise.
Phyphox uses the first sensor event it receives to set the beginning of the measurement to "zero", which is not really consistent across multiple sensors due to our poor implementation of this. I plan to improve this eventually, but this will mostly be done by making the system time of the start available to the user. The problem is that uptime is a very precise and reliable measure while system time can be very tricky as it can be adjusted at any time. Uptime is used to avoid "jumps" when the system adjusts the clock and for the same reason we cannot simply output our data with absolute time stamps, but will need to add a point of reference instead.
Phyphox uses the first sensor event it receives to set the beginning of the measurement to "zero", which is not really consistent across multiple sensors due to our poor implementation of this. I plan to improve this eventually, but this will mostly be done by making the system time of the start available to the user. The problem is that uptime is a very precise and reliable measure while system time can be very tricky as it can be adjusted at any time. Uptime is used to avoid "jumps" when the system adjusts the clock and for the same reason we cannot simply output our data with absolute time stamps, but will need to add a point of reference instead.