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Need help with odd raw data please.
Posted: Mon Mar 31, 2008 10:01 am
by cells
Hello gents, I am trying to use audacity in an odd way.
I have an accelerometer hooked up to audacity, which is acting basically like a microphone.
Actually I have the accelerometer writing a raw data file and audacity reading that data file.
I can’t seem to get audacity to understand the raw file though.
It is a time based voltage signal. With max of 5 and min of –5.
Here is an example of a little bit of the raw data
-0.083
-2.554
-1.948
0.818
1.421
-0.049
-0.464
-0.132
-0.059
1.06
1.619
0.671
0.889
I would be extremely grateful for any help
Thanks in advance.
Re: Need help with odd raw data please.
Posted: Mon Mar 31, 2008 4:54 pm
by kozikowski
I'm going with no. Audacity isn't going to know how to handle data unless it comes in a sound wrapper like WAV--in your case, only WAV. You can't use any of the compressed formats because they all damage data. Audacity will handle data down to DC which is where your data is. "Sound" officially stops at 20 cycles per second.
How were you planning on managing the data once you got it in?
Koz
Re: Need help with odd raw data please.
Posted: Tue Apr 01, 2008 9:15 am
by cells
kozikowski wrote:I'm going with no. Audacity isn't going to know how to handle data unless it comes in a sound wrapper like WAV--in your case, only WAV. You can't use any of the compressed formats because they all damage data. Audacity will handle data down to DC which is where your data is. "Sound" officially stops at 20 cycles per second.
How were you planning on managing the data once you got it in?
Koz
hi, audacity can take raw data, just not in any format
the signal I am getting is 500HZ so it should be fine.
think of a pure tone of say 100 HZ and your sampling it at 400 HZ you would get the following reading
0.00
1.00
0.00
-1.00
0.00
1.00
0.00
-1.00
ect
im just asking how i can get audacity to understand that.
once in audacity i plan on using the spectrogram feature to determine what frequencies make up the signal.
thanks
Re: Need help with odd raw data please.
Posted: Wed Apr 02, 2008 11:02 am
by cells
WOOT i figured it out
if you want audio software to understand raw files you need to base it from 0 - 256 (for 8 bit)
so all i had to do was change my scale from -5 to +5 to the understandable 0- 256
I still cant get audacity to understad it, but it seems cool edit pro can. so i use that to turn the txt to wav and then audacity to read the wav file
long way round, but at lest it works

Re: Need help with odd raw data please.
Posted: Wed Apr 02, 2008 1:46 pm
by kozikowski
Call me crazy, but why didn't you use the spectrogram features inside Cool Edit to do the tests?
Koz
Re: Need help with odd raw data please.
Posted: Thu Apr 03, 2008 7:28 am
by cells
YOUR CRAZY
i havent used COOL EDIT before so i didnt know it had that feature. i will use it now though
anyone know if there is a COOL EDIT like program that is free? my trail runs out in about 20 days
