#
# Beaglebone taxi sign driver
#
# Author: Jonas Berg
# Copyright (c) 2015, Semcon Sweden AB
# All rights reserved.
#
# Redistribution and use in source and binary forms, with or without modification, are permitted
# provided that the following conditions are met:
# 1. Redistributions of source code must retain the above copyright notice,
# this list of conditions and the following disclaimer.
# 2. Redistributions in binary form must reproduce the above copyright notice, this list of conditions and
# the following disclaimer in the documentation and/or other materials provided with the distribution.
# 3. Neither the name of the Semcon Sweden AB nor the names of its contributors may be used to endorse or
# promote products derived from this software without specific prior written permission.
#
# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
# AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
# DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
# FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
# DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
# SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
# CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
# OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
#
#
#
# For Python 2.7 and up (incl. 3.x)
# The script must be executed with root permissions
#
# Connect a relay driver from Beaglebone port8 pin3.
# The voltage is 3.3 V on the pin.
# The output is gpmc_ad6 = GPIO1_6
# This is GPIO 38 (1*32 + 6)
#
# +5 V is available on port9 pin7 and pin8.
# GND is available on port9 pin1 and pin2.
#
# If the relay and its driver circuit are connected such
# that the taxi sign turns off for GPIO=high,
# then use IS_INVERTED = True
#
# If using a LED instead, connect it to ground via 470 Ohm.
#
import output_pin_driver
# Hardware-describing constants
GPIO_NUMBER = 60
IS_INVERTED = True
[docs]class Taxisign(object):
"""Taxi sign representation.
For controlling a Taxi sign from a Beaglebone. This is basically the
Beaglebone output_pin_driver, together with hardware-describing constants.
Module constants describing the hardware:
* GPIO_NUMBER (int): GPIO number for pin connected to relay driver circuit.
* IS_INVERTED (bool): Set to True if the relay and its driver circuit
are connected such that the taxi sign turns off for GPIO=high.
Attributes:
* state (bool): Set to True to turn on the taxi sign.
"""
def __init__(self):
self._pin = output_pin_driver.Outputpin(GPIO_NUMBER)
self._is_inverted = IS_INVERTED
self.state = False
@property
def state(self):
return self._pin.state ^ self._is_inverted # XOR: Apply inversion if required
@state.setter
def state(self, value):
self._pin.state = value ^ self._is_inverted # XOR: Apply inversion if required
[docs] def loop(self):
# Graphical taxi sign simulators must update the GUI frequently. Not required here.
pass
#########################
## Testing the module ##
#########################
if __name__ == '__main__':
import time
sign = Taxisign()
sign.state = True
time.sleep(1)
sign.state = False
time.sleep(1)
sign.state = True
time.sleep(1)
sign.state = False