Can we set the data rate for accelerometer sensor??

[chandran.biju007]

Hi,
I would like to understand if we can set the data rate/frequency of the accelerometer sensor in JSR 256.
If no , then can we find the existing frequency.

It is possible in Symbian to get the property to AccelerometerXYZ and then set the property.
Is that doable in J2ME?

Regards
Biju

[chandran.biju007]

The API documentation says that by default the frequency is 40Hz and we cannot set the frequency in Java.
So i understand that if i set the BufferSize to 1,the DataReceived should be called 40 times in a second or if i set the BufferSize to 40,then it should be called once every second. But for 40 , it is called only once in around 3secs. For my processing of the samples it is important i know the sampling rate and it not vary.. IS it doable in J2ME? Or else what can be done and what not ??

[Tiger79]

I am afraid that the API documentation is all we got, if there are no methods thet meet your desired funcitonality then you can stop looking, you won';t be able to access the accelerometer in any other way than that api... maybe symbian/c++ gives more control, but it is known that j2me doesn't go very "deep" when it comes to hardware-interfaces...

[chandran.biju007]

Ok Tiger. So if it the document says it is 40Hz so i can safely trust the docs. Maybe i am getting it a bit slower because printing on screen at that rate would not be possible

[Tiger79]

I have no idea what the max fps can be of a device, I do know some games do 25-30 fps so that should be achievable whilst printing to screen...
Are you printing every single time to screen ? Or are you simply saving the system time when such a measurement is passed to your app and after some time (lets say 10 seconds) you print them all ?

[chandran.biju007]

Hi Tiger. I am testing on a N97 and like i mentioned before i can set a neat 50hz in SYmbian C++.
Basically i set the buffer size to 40 and in Data received it print on screen. So with 40 fps , it should print every second as the buffer reaches 40 only in intervals of a second.
But the print happens only once every 3 secs or so. This means that the default fps is slower than 40 or am I doing something wrong.

[Tiger79]

ok but instead of writing the data received try to write the systemtime in that 40-items buffer, and then retrieve the first and the last and compare the time...

[chandran.biju007]

Ok..Will try that and let you know..