search

phyphox / phyphox-android

Physical Phone Experiments
GNU General Public License v3.0
337 stars 44 forks source link

Sonar processing limits #67

Open Noitarud opened 6 months ago

Noitarud commented 6 months ago

My phone appears to be having troubles with showing data (screen updates slow and dis/reappearing or incomplete graphs).

I notice the first screen has history so this means all the graphs are running. There are no options so I cannot hide and disable pages…

Staacks commented 6 months ago

Can you provide a screenshot and a description of the experimental setup?

The sonar measurement is a bit tricky (and to be honest - if it had not been there since the beginning of phyphox I would no longer include it as a standard experiment) and there are two common problems: a) Sometimes the timing of sending sound and recording it can be wrong on some devices, so the echo is never recorded and a measurement becomes impossible. I have not seen this in a while, but in earlier version we ran into this problem several times and I would not rule it our entirely. b) A single missed measurement can lead to very high values, which impacts the autoscaling of the graphs, so other measurements become more or less invisible until the bad measurement is shifted out of the history.

Could it be any of these?

Noitarud commented 5 months ago

It was measuring the distance to a wall so I didn't need a ruler.

Yes, the other issue was inconsistent results (i should see things being still or move away). The tablet i have can play and record sounds at the same time (used camera record and played a song) and the first heard would be through device or shortest path, missing measurements ought not be possible. I can play from two apps at the same time (if both do not want exclusive use), so could probably record twice in the same (if it must).

So ramping is from a missed measurement? Couldn't it have a null input or use a copy of last if it missed something?

My first concern was updating all graphs rather than just the ones on screen would slow it down and harm the results (I was looking at the echo-location tab), though graphs probably aren't that much burden though…

This one is a Galaxy A11, dual mic. Which does it use? Video record: bottom mic is Left,top is Right, loudspeaker on bottom. Some devices have two speakers (the performance would vary between them and together could mar the results).