Ticket #63: weighdemo.py

#!/usr/bin/python
import sys
sys.path.insert(0, '/home/tbble/code/cwiid/svn/cwiid/python/build/lib.linux-x86_64-2.5/')
import cwiid
import sys

def main():
        #Connect to address given on command-line, if present
        print 'Put Wiimote in discoverable mode now (press 1+2)...'
        global wiimote
        if len(sys.argv) > 1:
                wiimote = cwiid.Wiimote(sys.argv[1])
        else:
                wiimote = cwiid.Wiimote()

        wiimote.rpt_mode = cwiid.RPT_BALANCE | cwiid.RPT_BTN
        wiimote.request_status()

        if wiimote.state['ext_type'] != cwiid.EXT_BALANCE:
                print 'This program only supports the Wii Balance Board'
                wiimote.close()
                return -1

        balance_calibration = wiimote.get_balance_cal()
        named_calibration = { 'right_top': balance_calibration[0],
                                                  'right_bottom': balance_calibration[1],
                                                  'left_top': balance_calibration[2],
                                                  'left_bottom': balance_calibration[3],
                                                }

        exit = False
        while not exit:
                print "Type q to quit, or anything else to report your weight"
                c = sys.stdin.read(1)
                if c == 'q':
                        exit = True
                wiimote.request_status()
                print "%.2fkg" % (calcweight(wiimote.state['balance'], named_calibration) / 100.0, )

        return 0

def calcweight( readings, calibrations ):
        """
        Determine the weight of the user on the board in hundredths of a kilogram
        """
        weight = 0
        for sensor in ('right_top', 'right_bottom', 'left_top', 'left_bottom'):
                reading = readings[sensor]
                calibration = calibrations[sensor]
#               if reading < calibration[0]:
#                       print "Warning, %s reading below lower calibration value" % sensor
                if reading > calibration[2]:
                        print "Warning, %s reading above upper calibration value" % sensor
                # 1700 appears to be the step the calibrations are against.
                # 17kg per sensor is 68kg, 1/2 of the advertised Japanese weight limit.
                if reading < calibration[1]:
                        weight += 1700 * (reading - calibration[0]) / (calibration[1] - calibration[0])
                else:
                        weight += 1700 * (reading - calibration[1]) / (calibration[2] - calibration[1]) + 1700

        return weight

if __name__ == "__main__":
        sys.exit(main())