Comedi Record
Highlights
- Records from multiple USBDUX boards
- DC filter
- Fast 50Hz filtering
- Can receive external data/text via a TCP port, for example telnet for comments etc
What is it?
comedirecord is an oscilloscope program to display and record data from a COMEDI device. Its philosophy is to save the data in its original form at the maximum sampling rate but allows comfortable viewing of the data during an experiment.
An IIR notch filter has been implemented to filter out unwanted hum. This might be useful for medical applications. The frequency can be changed via a commandline parameter.
The output format is ASCII. The data can be imported into GNUPLOT, scilab or octave. The first column is the sample number (RAW on) or the time in seconds (RAW off). The next columns represent the (raw/physical) data from the comedi device.
From version 1.1 you can aquire data from multiple USBDUX boards simultaneously and also append data via an TCP port connection which could be a telnet connection into comedirecord or data from another program. Check out the command line parameters with "comedirecord -h" or the man page.
From version 1.2 a DC filter can be switched on which removes the DC from the plot which is useful when observing small voltage changes at a high gain. The DC filter measures the DC while switched off. When switched on the DC value is frozen and subtracted from the plotted data.
Download
- comedirecord-1.22.tar.gz source
-
UBUNTU repository for lucid and precise. Just add "ppa:berndporr/usbdux"
to your package manager or run in the termninal:
sudo add-apt-repository ppa:berndporr/usbdux
- comedirecord_1.22_i386.deb (compiled under UBUNTU Lucid)
- comedirecord-1.0.tar.gz (QT4,internal 50Hz filtering)
- comedirecord-0.94.tar.gz (QT3)
A quick guide describing how to import the data into GNU's octave
This code fragment imports the data file "myname5.dat" into the variables x and t
- load myname5.dat
- x=myname5(:,2); % data
- t=myname5(:,1); % time
- plot(x);
- plot(abs(fft(x)));
...and a quick guide how to import the data into scilab
- -->ecg=read('long_ecg.dat',-1,2); % loads the first two columns
- -->y=ecg(:,2); % get the data
- -->plot(y);
