# SevenBitBargraph2x.py
#
# A DEMO 7 bit analogue bargraph generator in colour for STANDARD Python 2.x and Linux...
#
# (Original copyright, (C)2010, B.Walker, G0LCU.)
# A Python 3.x version can be found here:-
# http://www.linuxformat.com/forums/viewtopic.php?t=13443
#
# Saved as SevenBitBargraph2x.py wherever you like.
#
# This DEMO goes from safe green, to warning amber, to danger red, with a crirical
# error beep above 120 on the horizontal scale...
#
# Two system commands are required, "clear" and "setterm", for this to work.
# I assume that these are available on all recent and current Linux distros.
# The device /dev/audio is used so this must be free also.
#
# It is useful for quick glance readings from say an 8 bit ADC used as a simple
# voltmeter, etc. Getting a digital readout is SO simple I left it out this time...
#
# To run use the following from inside a Python prompt...
# >>> exec(open("/full/path/to/code/SevenBitBargraph2x.py").read())
# OR...
# >>> execfile("/full/path/to/code/SevenBitBargraph2x.py").read()
# Tested on PCLinuxOS 2009 with Python 2.5.2, and, Debian 6.0.0 with Python 2.6.6.
# Add the required imports for this DEMO.
import os
import random
import time
def main():
# For this DEMO set up variables as global...
global column
global count
global bargraph
column=0
count=2
bargraph="(C)2010, B.Walker, G0CLU. Now Public Domain"
# Disable the cursor as it looks much nicer... ;o)
os.system("setterm -cursor off")
while 1:
# Do a full, clean, clear screen and start looping.
print os.system("clear"),unichr(13)," ",unichr(13),
# Set to terminal default colour(s).
print "\033[0mSeven Bit Level Horizontal Analogue Bar Graph Display..."
print
print "Original copyright, (C)2010, B.Walker, G0LCU."
print
print "Issued to all as Public Domain."
print
print
# Set the bargraph to light green for this DEMO.
# This is equivalent to 0 for the column value.
bargraph=" \033[1;32m|"
# Generate a byte value as though grabbed from a serial, parallel or USB port.
column=int(random.random()*256)
# Now divide by 2 to simulate a 7 bit value.
column=int(column/2)
# Although this should never occur, don't allow any error.
if column>=127: column=127
if column<=0: column=0
# Now to generate the bargraph...
count=0
while count<=column:
# It is equivalent to BIOS character 222 for column value of 1 ONLY.
if count==1: bargraph=" \033[1;32m"+unichr(0x2590)
count=count+1
if count>=2:
while count<=column:
# Change bargraph colour on the fly when entering the YELLOW zone... :)
if count>=90: bargraph=bargraph+"\033[1;33m"
# Change bargraph colour on the fly when entering the RED zone... :)
if count>=100: bargraph=bargraph+"\033[1;31m"
if count%2==0:
# For every odd column value print this BIOS character 221.
bargraph=bargraph+unichr(0x258c)
if count%2==1:
# For every even column value OVERWRITE the above with BIOS character 219.
bargraph=bargraph+"\b"+unichr(0x2588)
count=count+1
# Print the "scale" in the default colour(s)...
print "\033[0m 0 10 20 30 40 50 60 70 80 90 100 110 120"
# Now print the meter and bargraph in colours of your choice... :)
print "\033[1;32m | | | | | | | | | \033[1;33m| \033[1;31m| | |"
print "\033[1;32m +++++++++++++++++++++++++++++++++++++++++++++\033[1;33m+++++\033[1;31m+++++++++++++++"
print bargraph
print "\033[1;32m +++++++++++++++++++++++++++++++++++++++++++++\033[1;33m+++++\033[1;31m+++++++++++++++"
print
print " \033[1;34m Analogue resolution is half of one division, that is 1."
print
# Return back to the default colours and for this DEMO the column value...
print "\033[0mColumn number",column,"\b... "
print
print "Press Ctrl-C to stop..."
# Do a critical error beep, [sine wave(ish)] for about 1second.
if column>=120:
# Set up the binary code as a crude sinewave.
waveform=b"\x0f\x2d\x3f\x2d\x0f\x03\x00\x03"
# Set audio timing to zero, "0".
count=0
# Open up the audio device to write to.
# This could be /dev/dsp also...
audio=open("/dev/audio", "wb")
# A "count" value of 1 = 1mS, so 1000 = 1S.
while count<=1000:
# Send 8 bytes of data to the audio device 1000 times.
# This is VERY close to 1KHz and almost sinewave.
audio.write(waveform)
count=count+1
# Close the audio device access.
audio.close()
# Add a DEMO delay to simulate a simple digital voltmeter speed...
if column<=119: time.sleep(1)
# Enable the cursor again if it ever gets here... ;oO
os.system("setterm -cursor on")
main()
# DEMO end.
# Enjoy finding simple solutions to often very difficult problems...
