Printing heading output

Simply print the output from pixhawk to the screen. This is useful if only to verify that it is working at all.

from zoidberg import PixhawkNode, pause
from serial import SerialException
from time import time

update_period = 0.05
# Mac OSX address of pixhawk
#device = '/dev/tty.usbmodem1'
device = '/dev/ttyACM0'
pn = PixhawkNode(device)

# try loop is used to ensure that communication with pixhawk is
# terminated.
try:
    # startup data stream
    pn.isactive(True)
    while True:
        loop_start = time()
        pn.check_readings()
        print("Current heading: %.2f"%pn.heading)
        # sleep to maintain constant rate
        pause(loop_start, update_period)
except SerialException:
    print('Pixhawk is not connected to %s'%device)
finally:
    print('Shutting down communication with Pixhawk')
    pn.isactive(False)