Merge pull request #1 from FrozenFire/master

Addition of E axis calibration program and adding of *.pyc to .gitignore.

.gitignore

+*.pyc

calibrateextruder.py

+#!/usr/bin/python
+#Interactive RepRap e axis calibration program
+#(C) Nathan Zadoks 2011
+#Licensed under CC-BY-SA or GPLv2 and higher - Pick your poison.
+t= 60			#Time to wait for extrusion
+n=100			#Default length to extrude
+m=  0			#User-entered measured extrusion length
+k=300			#Default amount of steps per mm
+port='/dev/ttyUSB0'	#Default serial port to connect to printer
+
+try:
+	from printdummy import printcore
+except ImportError:
+	from printcore import printcore
+import time,getopt,sys
+
+def float_input(prompt=''):
+	import sys
+	f=None
+	while f==None:
+		s=raw_input(prompt)
+		try:
+			f=float(s)
+		except ValueError:
+			sys.stderr.write("Not a valid floating-point number.\n")
+			sys.stderr.flush()
+	return f
+def wait(t,m=''):
+	import time,sys
+	sys.stdout.write(m+'['+(' '*t)+']\r'+m+'[')
+	sys.stdout.flush()
+	for i in range(t):
+		for s in ['|\b','/\b','-\b','\\\b','|']:
+			sys.stdout.write(s)
+			sys.stdout.flush()
+			time.sleep(1.0/5)
+	print
+
+#Parse options
+help="""
+%s [ -l DISTANCE ] [ -s STEPS ] [ -p PORT ]
+	-l	--length	Length of filament to extrude for each calibration step (default: %d mm)
+	-s	--steps		Initial amount of steps to use (default: %d steps)
+	-p	--port		Serial port the printer is connected to (default: %s)
+	-h	--help		This cruft.
+"""[1:-1]%(sys.argv[0],n,k,port)
+try:
+	opts,args=getopt.getopt(sys.argv[1:],"hl:s:p:",["help","length=","steps=","port="])
+except getopt.GetoptError,err:
+	print str(err)
+	print help
+	sys.exit(2)
+for o,a in opts:
+	if o in ('-h','--help'):
+		print help
+		sys.exit()
+	elif o in ('-l','--length'):
+		n=float(a)
+	elif o in ('-s','--steps'):
+		k=int(a)
+
+#Show initial parameters
+print "Initial parameters"
+print "Steps per mm:    %3d steps"%k
+print "Length extruded: %3d mm"%n
+print 
+print "Serial port:     %s"%port
+
+#Connect to printer
+print "Connecting to printer..",
+p=printcore(port,115200)
+print "connected."
+
+#Calibration loop
+while n!=m:
+	p.send_now("G92 E0")			#Reset e axis
+	p.send_now("G1 E%d F100"%int(n))	#Extrude length of filament
+	wait(t,'Extruding.. ')
+	m=float_input("How many millimeters of filament were extruded? ")
+	if n!=m:
+		k=(n/m)*k
+		p.send_now("M92 E%d"%int(round(k)))	#Set new step count
+		print "Steps per mm:    %3d steps"%k	#Tell user
+print 'Calibration completed.'	#Yay!
+p.disconnect()