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89 lines
2.2 KiB
Python
Executable File
89 lines
2.2 KiB
Python
Executable File
#!/usr/bin/python
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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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import signal
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def signal_handler(sig, frame):
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sys.exit(0)
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signal.signal(signal.SIGINT, signal_handler)
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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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SLEEP = 0.5
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MAX_DIST = 400
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def Measure():
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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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stop = 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, Restart.")
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time.sleep(0.4)
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return 400
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while GPIO.input(ECHO)==1:
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stop = time.time()
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Dif = time.time() - realstart
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if Dif > 0.4:
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print("Ultrasonic Sensor Timed out, Restarting.")
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time.sleep(0.2)
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return 400
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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) != 3:
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print("Bad parameters 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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SLEEP = float(pins[2])
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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.output(TRIGGER, False)
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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 and distance > 2 and distance < 400:
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print(distance)
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OLD = distance
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time.sleep(SLEEP)
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except: # try to clean up on exit
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print("0.0")
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else:
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print("Bad params")
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print(" nrsrf.py trigger_pin, echo_pin, rate_in_seconds")
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sys.exit(0)
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