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92 lines
2.4 KiB
Python
Executable File
92 lines
2.4 KiB
Python
Executable File
#!/usr/bin/python
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#
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# Copyright 2015 IBM Corp.
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#
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# Licensed under the Apache License, Version 2.0 (the "License");
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# you may not use this file except in compliance with the License.
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# You may obtain a copy of the License at
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# http://www.apache.org/licenses/LICENSE-2.0
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS,
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# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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# See the License for the specific language governing permissions and
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# limitations under the License.
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# Python driver for SRF04 and SRO05 Ultrasonic sensors
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# Modified to use PINS not BCM : Dave Conway-Jones
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#import
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import RPi.GPIO as GPIO
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import time
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import sys
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import os, select
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# Turn off warnings if you run it a second time...
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GPIO.setwarnings(False)
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ECHO = 0
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TRIGGER = 0
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OLD = 0
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def Measure():
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start = 0
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realstart = 0
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realstart = time.time()
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GPIO.output(TRIGGER, True)
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time.sleep(0.00001)
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GPIO.output(TRIGGER, False)
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start = time.time()
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while GPIO.input(ECHO)==0:
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start = time.time()
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Dif = time.time() - realstart
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if Dif > 0.2:
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print("Ultrasonic Sensor Timed out, Restarting.")
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time.sleep(0.4)
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Main()
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while GPIO.input(ECHO)==1:
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stop = time.time()
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elapsed = stop-start
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distance = (elapsed * 36000)/2
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return distance
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# Main program loop
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if len(sys.argv) > 1:
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pins = sys.argv[1].lower().split(',')
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if len(pins) != 2:
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print "Bad number of pins supplied"
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print pins
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sys.exit(0)
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TRIGGER = int(pins[0])
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ECHO = int(pins[1])
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GPIO.setmode(GPIO.BOARD) # Use GPIO BOARD numbers
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GPIO.setup(TRIGGER, GPIO.OUT) # Trigger
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GPIO.setup(ECHO, GPIO.OUT) # Echo
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GPIO.output(ECHO, False)
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GPIO.setup(ECHO,GPIO.IN)
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# Flush stdin so we start clean
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while len(select.select([sys.stdin.fileno()], [], [], 0.0)[0])>0:
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os.read(sys.stdin.fileno(), 4096)
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while True:
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try:
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distance = int( Measure() + 0.5 )
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if distance != OLD:
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print(distance)
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OLD = distance
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time.sleep(0.5)
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except: # try to clean up on exit
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print("0.0");
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GPIO.cleanup(TRIGGER)
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GPIO.cleanup(ECHO)
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sys.exit(0)
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else:
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print "Bad params"
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print " sudo nrsrf.py trigger_pin,echo_pin"
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sys.exit(0)
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