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damonkohler / sl4a

SL4A brings scripting languages to Android by allowing you to edit and execute scripts and interactive interpreters directly on the Android device.
Apache License 2.0
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Sensor event time stamp errors #166

Open damonkohler opened 9 years ago

damonkohler commented 9 years ago

From @GoogleCodeExporter on May 31, 2015 11:28

Sensor events entered into the event queue have a time stamp which 'sticks' for 
between 4 and 6 entries before updating. Run the following script:

import android, time
droid = android.Android()
t = time.time()
droid.startSensing()
time.sleep(2)
e = droid.eventPoll(60).result
for i in range(17,55):
  print e[i]['data']['time'] - t
droid.stopSensing()

You will get someting like:

0.763589143753
0.763589143753
0.764589071274
0.765588998795
0.765588998795
0.979588985443
0.980589151382
0.980589151382
0.983589172363
0.984589099884
0.986589193344
1.19458913803
1.19658899307
1.19658899307
1.19758915901
1.41658902168
1.41758918762
1.41758918762
1.41858911514
1.41958904266
1.42158913612
1.63858914375
1.63858914375
1.63858914375
1.63958907127
1.86158919334
1.86258912086
1.86258912086
1.86358904839
1.86458921432
1.86558914185
2.08958911896
2.09158921242
2.09158921242
2.09158921242
2.31058907509
2.31158900261
2.31258916855

This makes it impossible to relate readings to given points in time.

Original issue reported on code.google.com by joka...@gmail.com on 22 Feb 2011 at 10:36

Copied from original issue: damonkohler/android-scripting#522

damonkohler commented 9 years ago

From @GoogleCodeExporter on May 31, 2015 11:28

Reminder to Damon who suggested:

However, if the only concern here is adjusting the sensor delay, I 
think we could provide an API for that easily enough. 
I suggest: 
sensorsStartSensingFast() 
sensorsStartSensingSlow() 
sensorsStartSensing(int rateInEventsPerSecond)

Original comment by joka...@gmail.com on 9 Mar 2011 at 8:28