# 4BitVerticalBargraph2x.py
#
# A DEMO 4 bit slow analogue bargraph generator in colour for STANDARD Python 2.6.x and Linux...
# This is a vertical version of the horizontal one also given away by myself.
# It is written so that anyone can understand how it works.
#
# (Original copyright, (C)2011, B.Walker, G0LCU.)
# Issued initially to LXF as Public Domain, and to other sites later.
#
# Saved as 4BitVerticalBargraph2x.py wherever you like.
#
# This DEMO goes from safe green, to warning amber, to danger red, with a crirical
# error beep above 14 on the vertical scale...
# It is a slow "AT A GLANCE" display for quick assessments, not for accuracy.
#
# 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 "AT A GLANCE" readings from say an 8 bit ADC used as a simple
# voltmeter, ammeter, 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/4BitVerticalBargraph2x.py").read())
# OR...
# >>> execfile("/full/path/to/code/4BitVerticalBargraph2x.py")
#
# This looks like an "LED" style "VU" display...
# Add the required imports for this DEMO.
import os
import random
import time
# Just for this DEMO set up variables as global...
global count
global row
global blank
global greenlines
global yellowlines
global redlines
global waveform
# Startup variable values here.
count=0
row=0
blank="(C)2011, B.Walker, G0LCU."
greenlines=blank
yellowlines=blank
redlines=blank
# This is a square wave binary for the critical error beep.
waveform=chr(15)+chr(45)+chr(63)+chr(45)+chr(15)+chr(3)+chr(0)+chr(3)
def main():
# Disable the cursor as it looks much nicer... ;o)
os.system("setterm -cursor off")
while 1:
# Run continuously and use Ctrl-C to STOP!
count=15
blank="\033[0m "
# Generate a byte value as though grabbed from a serial, parallel or USB port.
row=int(random.random()*256)
# Now divide by 16 to simulate a 4 bit value.
row=int(row/16)
# Although this should never occur, don't allow any error.
if row>=15: row=15
if row<=0: row=0
while count>=0:
# Do a full, clean, clear screen and start looping.
os.system("clear"),chr(13)," ",chr(13),
print "\033[0mFour Bit Level Vertical Analogue Bar Graph Display..."
print "Original copyright, (C)2011, B.Walker, G0LCU."
print "Issued to LXF on 24-04-2011 as Public Domain."
print
print blank+"\033[1;31m15 __ "
redlines=blank+"\033[1;31m14 __ "
if row>=15: redlines=redlines+unichr(0x2588)+unichr(0x2588)
count=count-1
print redlines
redlines=blank+"\033[1;31m13 __ "
if row>=14: redlines=redlines+unichr(0x2588)+unichr(0x2588)
count=count-1
print redlines
yellowlines=blank+"\033[1;33m12 __ "
if row>=13: yellowlines=yellowlines+unichr(0x2588)+unichr(0x2588)
count=count-1
print yellowlines
yellowlines=blank+"\033[1;33m11 __ "
if row>=12: yellowlines=yellowlines+unichr(0x2588)+unichr(0x2588)
count=count-1
print yellowlines
yellowlines=blank+"\033[1;33m10 __ "
if row>=11: yellowlines=yellowlines+unichr(0x2588)+unichr(0x2588)
count=count-1
print yellowlines
greenlines=blank+"\033[1;32m 9 __ "
if row>=10: greenlines=greenlines+unichr(0x2588)+unichr(0x2588)
count=count-1
print greenlines
greenlines=blank+"\033[1;32m 8 __ "
if row>=9: greenlines=greenlines+unichr(0x2588)+unichr(0x2588)
count=count-1
print greenlines
greenlines=blank+"\033[1;32m 7 __ "
if row>=8: greenlines=greenlines+unichr(0x2588)+unichr(0x2588)
count=count-1
print greenlines
greenlines=blank+"\033[1;32m 6 __ "
if row>=7: greenlines=greenlines+unichr(0x2588)+unichr(0x2588)
count=count-1
print greenlines
greenlines=blank+"\033[1;32m 5 __ "
if row>=6: greenlines=greenlines+unichr(0x2588)+unichr(0x2588)
count=count-1
print greenlines
greenlines=blank+"\033[1;32m 4 __ "
if row>=5: greenlines=greenlines+unichr(0x2588)+unichr(0x2588)
count=count-1
print greenlines
greenlines=blank+"\033[1;32m 3 __ "
if row>=4: greenlines=greenlines+unichr(0x2588)+unichr(0x2588)
count=count-1
print greenlines
greenlines=blank+"\033[1;32m 2 __ "
if row>=3: greenlines=greenlines+unichr(0x2588)+unichr(0x2588)
count=count-1
print greenlines
greenlines=blank+"\033[1;32m 1 __ "
if row>=2: greenlines=greenlines+unichr(0x2588)+unichr(0x2588)
count=count-1
print greenlines
greenlines=blank+"\033[1;32m 0 __ "
if row>=1: greenlines=greenlines+unichr(0x2588)+unichr(0x2588)
count=count-1
if row==0: greenlines=greenlines+"__"
count=count-1
print greenlines
# Reset to default colours...
print
print "\033[0mPress Ctrl-C to stop..."
if row<=14: time.sleep(1)
if row==15:
# 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()
# Enable the cursor again if it ever gets here... ;oO
os.system("setterm -cursor on")
main()
# End of DEMO...
# Enjoy finding simple solutions to often very difficult problems...
