upm/examples/python/maxsonarez.py

#!/usr/bin/env python
# Author: Jon Trulson <jtrulson@ics.com>
# Copyright (c) 2015 Intel Corporation.
#
# Permission is hereby granted, free of charge, to any person obtaining
# a copy of this software and associated documentation files (the
# "Software"), to deal in the Software without restriction, including
# without limitation the rights to use, copy, modify, merge, publish,
# distribute, sublicense, and/or sell copies of the Software, and to
# permit persons to whom the Software is furnished to do so, subject to
# the following conditions:
#
# The above copyright notice and this permission notice shall be
# included in all copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
# EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
# MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
# NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
# LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
# OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
# WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

from __future__ import print_function
import time, sys, signal, atexit
from upm import pyupm_maxsonarez as MaxSonarEZ

def main():
    # Instantiate a MaxSonar-EZ on analog pin A1, with an analog
    # reference voltage of MAXSONAREZ_AREF
    Sonar = MaxSonarEZ.MAXSONAREZ(1)

    ## Exit handlers ##
    # This stops python from printing a stacktrace when you hit control-C
    def SIGINTHandler(signum, frame):
        raise SystemExit

    # This lets you run code on exit,
    # including functions from Sonar
    def exitHandler():
        print("Exiting")
        sys.exit(0)

    # Register exit handlers
    atexit.register(exitHandler)
    signal.signal(signal.SIGINT, SIGINTHandler)

    # analog voltage, usually 3.3 or 5.0
    MAXSONAREZ_AREF = 5.0;

    # Every second, sample the sonar and output the distance to an
    # object in inches.

    # With the EZ3 version, the minimum and maximum ranges seemed to be
    # between 6 and 33 inches

    while (1):
        print("AREF: {0}, distance in inches: {1}".format(
                MAXSONAREZ_AREF,
                Sonar.inches()))
        time.sleep(1)

if __name__ == '__main__':
    main()