# SimpleScope.py # A standard text mode Python Audio LF Oscilloscope DEMO. # # (This working idea WILL become the basis of a Data-Logger/Transient-Recorder # being worked on for Linux, Windows, Classic AMIGA and WinUAE using Arduino.) # # (Original working idea, (C)2010, B.Walker, G0LCU.) # Now issued as Public Domian. You may do as you please with this code. # # To run type at the Python prompt:- # >>> execfile('/full/path/to/file/SimpleScope.py') # Where "/full/path/to/file/" is the drawer(/folder/directory) that # "SimpleScope.py" resides. # # For this DEMO /dev/dsp must exist for it to work, if not, then install # oss-compat from your distro's repository. # Ensure the sound system is not in use by another application. # # Tested on PCLinuxOS 2009, Knoppix 5.1.1, (and Debian 6.0.0 <- WITH # oss-compat installed). # "setterm" and "clear" are assumed to be available. # # This is the only import required for this working DEMO. import os def main(): # Set everything as global for this DEMO. global ScopeScreen global ScopeWindow global audio global plot global position global horiz global record global grab # Allocate values. ScopeScreen="(C)2011, B.Walker, G0LCU." ScopeWindow="Simple LF Audio Oscilloscope." audio="/dev/dsp" plot=0 position=67 horiz=0 record=" " grab=255 # Turn off the cursor. os.system("setterm -cursor off") while 1: # This is the basic Osilloscope graticule window for this DEMO. ScopeScreen="+-------+-------+-------+-------+-------+-------+-------+--------+\n" ScopeScreen=ScopeScreen+"| | | | + | | | |\n" ScopeScreen=ScopeScreen+"| | | | + | | | |\n" ScopeScreen=ScopeScreen+"| | | | + | | | |\n" ScopeScreen=ScopeScreen+"| | | | + | | | |\n" ScopeScreen=ScopeScreen+"+-------+-------+-------+-------+-------+-------+-------+--------+\n" ScopeScreen=ScopeScreen+"| | | | + | | | |\n" ScopeScreen=ScopeScreen+"| | | | + | | | |\n" ScopeScreen=ScopeScreen+"| | | | + | | | |\n" ScopeScreen=ScopeScreen+"+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-++\n" ScopeScreen=ScopeScreen+"| | | | + | | | |\n" ScopeScreen=ScopeScreen+"| | | | + | | | |\n" ScopeScreen=ScopeScreen+"| | | | + | | | |\n" ScopeScreen=ScopeScreen+"+-------+-------+-------+-------+-------+-------+-------+--------+\n" ScopeScreen=ScopeScreen+"| | | | + | | | |\n" ScopeScreen=ScopeScreen+"| | | | + | | | |\n" ScopeScreen=ScopeScreen+"| | | | + | | | |\n" ScopeScreen=ScopeScreen+"+-------+-------+-------+-------+-------+-------+-------+--------+\n" # Save the this graticule window for further writing to. ScopeWindow=open("/tmp/ScopeScreen.txt","wb+") ScopeWindow.write(ScopeScreen) ScopeWindow.close() # Grab a string of 64 bytes in size at 8KHz sampling speed. # If you have an internal microphone just shout into it and # see a 4 bit depth waveform of you voice. # Alternatively feed a signal into the external mic input socket # and adjust the levels using the I/P and O/P volume control mixers. audio=file("/dev/dsp","rb") record=audio.read(64) audio.close() horiz=0 ScopeWindow=open("/tmp/ScopeScreen.txt","rb+") while horiz<=63: # Convert each part of the record string into decimal. grab=ord(record[horiz]) # Now convert to 4 bit depth for text mode display. plot=int(grab/16) # Invert to suit the text display window. plot=15-plot # Don't allow an error. if plot<=0: plot=0 if plot>=15: plot=15 # Set up the horizontal position and plot. position=68+horiz+plot*67 ScopeWindow.seek(position) ScopeWindow.write("o") horiz=horiz+1 # Now get the whole ScopeWindow with the plotted points...... ScopeWindow.seek(0) ScopeScreen=ScopeWindow.read(1206) ScopeWindow.close() # ......and print it to the terminal window. print os.system("clear"),chr(13)," ",chr(13), print ScopeScreen print "Simple Audio Oscilloscope DEMO using /dev/dsp in Linux." print "Ctrl-C to quit..." # Reset the cursor assuming it gets here... ;o) os.system("setterm -cursor on") main() # SimpleScope.py program end. # Enjoy finding simple solutions to often very difficult problems.