Test of i2c accelerometer + raspberry pi

i2c_accelerometer.py

#!/usr/bin/python

import smbus
import time

# Plot a graph of the z-axis acceleration using a Raspberry Pi connected
# to one of these: http://www.pololu.com/catalog/product/1250
# Datasheet: http://www.pololu.com/file/download/LSM303DLH.pdf?file_id=0J433

def main():
  bus = smbus.SMBus(1)

	# Power-on the accelerometer, enabling only the z-axis
	bus.write_byte_data(0x18, 0x20, 0x24)

	try:
		while True:
      # get z-axis acceleration
			tilt = bus.read_byte_data(0x18, 0x2D)

      # if it's supposed to be negative
			if tilt > 127:
        # then convert it to the absolute value of the negative value
				tilt = 256 + ~tilt
				positive = False
			else:
				positive = True

      # format and print it
			pos = tilt / 2
			print str(tilt).rjust(6),
			if positive:
				print 65*' ' + '|' + (pos*'#').ljust(65)
			else:
				print (pos*'#').rjust(65) + '|' + 65*' '
			
      # sleep
      time.sleep(0.1)
      
	except KeyboardInterrupt:
		# restore default settings
		bus.write_byte_data(0x18, 0x20, 0x07)

if __name__ == '__main__':
	main()