Playing around with xwiimote to make a weigh scale

scale.py

#!/usr/bin/env python

import errno
from sys import stdout
from time import sleep
from select import poll, POLLIN
from inspect import getmembers
import xwiimote

def get_device(entry):
	if entry is None:
		return None

	try:
		dev = xwiimote.iface(entry)
		print "Found", dev.get_devtype()
		dev.opened()
		dev.open(dev.available() | xwiimote.IFACE_WRITABLE)

		return dev
	except IOError as e:
		print "Error:", e
		return None

def get_balance_board():
	bb = None
	try:
		mon = xwiimote.monitor(True, True)
		count = 0
		while bb is None:
			stdout.write("Waiting {0}...\r".format(count))
			stdout.flush()

			bb = get_device(mon.poll())

			count += 1
			sleep(1)

		return bb
	except SystemError as e:
		print "Monitor error:",e

while True:
	dev = get_balance_board()

	# display some information and open the iface
	try:
		print "Battery:",  dev.get_battery(), "%"
	except SystemError as e:
		print "ooops", e
		exit(1)

	p = poll()
	p.register(dev.get_fd(), POLLIN)
	evt = xwiimote.event()
	n = 0
	while n < 2:
		p.poll()
		try:
			dev.dispatch(evt)
			if evt.type == xwiimote.EVENT_KEY:
				code, state = evt.get_key()
				print "Key:", code, ", State:", state
				n+=1
			elif evt.type == xwiimote.EVENT_GONE:
				print "Gone"
				n = 2
			elif evt.type == xwiimote.EVENT_WATCH:
				print "Watch"
			elif evt.type == xwiimote.EVENT_BALANCE_BOARD:
				br, _, _ = evt.get_abs(0)
				fr, _, _ = evt.get_abs(1)
				bl, _, _  = evt.get_abs(2)
				fl, _, _  = evt.get_abs(3)

				weight = (br + fr + bl + fl) / 100.0
			
				stdout.write("{:3.1f} kg    \r".format(weight))
				stdout.flush()
			else:
				if evt.type != xwiimote.EVENT_ACCEL:
					print "type:", evt.type
		except IOError as e:
			if e.errno != errno.EAGAIN:
				print "Bad"