From: Joerg Hansmann (jhansmann_at_g...)
Date: 2000-12-01 14:16:00
Hi Rob,
----- Original Message -----
From: Rob Sacks <editor_at_realization.org>
To: buildcheapeeg <buildcheapeeg_at_egroups.com>
Sent: Thursday, November 30, 2000 7:24 PM
Subject: Re: [buildcheapeeg] Re: hi folks
> Joerg,
>
> (If I write your name this way, Jörg, does it work?)
Yes. It looks right. ( A little trick with the ALT-Key ? )
> > Sounds nice. I am really interested in samples of brainwaves of a meditating
> > lama. Perhaps Rob could add the feature of recording / viewing
> > eeg-data files.
>
> What should we put in the files?
e.g.
1 header:
4 bytes version_code
80 char short_description
1 byte number_of_channels
1 byte bytes_per_channel
?? bytes date_and_time_of_recording_start
n data-blocks:
1 byte ch1_hi
1 byte ch1_lo
1 byte ch2_hi
1 byte ch2_lo
...
1 byte chn_hi
1 byte chn_lo
------------end_of_format_description-----------
As an alternative we could use a data format of commercial
eeg data logger.
> If we store all
> the data (the raw serial input or the microvoltages)
> the files will be very big.
If you provide a dialog to store only channels that are used,
the amount of data will be quite moderate for modern PCs.
1 second : 256Hz * 2 channels * 2byte/channel = 1024 bytes
1 minute : 60* 1024 bytes = 61 kB
1 hour: 60* 61kB = 3.7 MB
24 h : 24* 3.7 MB= 88 MB
Lets assume , the lama meditates 1 h , then we would get 3.7 MB
raw data. Compressed to ZIP -Format it will be below 1 MB
Regards,
Joerg
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