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Code Issues Releases Wiki Activity

Improve restart upon timeout (#338) (#353)

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* Print error on exception and tweak GPIO setup

* Restart script on timeout

* Add GPIO.cleanup to restart() function

* Use interrupts instead of polling input pin state
This commit is contained in:
denisfrench 2017-09-08 06:12:33 +10:00 committed by Dave Conway-Jones
parent e376802ff4
commit e61da83d5d
1 changed files with 35 additions and 26 deletions
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61
hardware/PiSrf/nrsrf.py
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@ -19,32 +19,44 @@ SLEEP = 0.5
def Measure(): def Measure():
start = 0 start = 0
realstart = 0
realstart = time.time()
GPIO.output(TRIGGER, True) GPIO.output(TRIGGER, True)
time.sleep(0.00001) time.sleep(0.00001)
GPIO.output(TRIGGER, False) GPIO.output(TRIGGER, False)
start = time.time()
while GPIO.input(ECHO)==0:
start = time.time()
Dif = time.time() - realstart
if Dif > 0.2:
print("Ultrasonic Sensor Timed out, Restarting.")
time.sleep(0.4)
Main()
while GPIO.input(ECHO)==1:
stop = time.time()
Dif = time.time() - realstart
if Dif > 0.4:
print("Ultrasonic Sensor Timed out, Restarting.")
time.sleep(0.2)
Main()
channel = GPIO.wait_for_edge(ECHO, GPIO.BOTH, timeout=200)
if channel is None:
print("Ultrasonic sensor timed out (pre-echo).")
GPIO.remove_event_detect(ECHO)
restart()
# else:
# print("Echo start detected")
start = time.time()
GPIO.wait_for_edge(ECHO, GPIO.BOTH, timeout=400)
if channel is None:
print("Ultrasonic sensor timed out (post-echo).")
GPIO.remove_event_detect(ECHO)
restart()
# else:
# print("Echo finish detected")
stop = time.time()
elapsed = stop-start elapsed = stop-start
distance = (elapsed * 36000)/2 distance = (elapsed * 34300)/2 # Using speed of sound at 20C (68F)
return distance return distance
def restart():
# print("Restarting...")
GPIO.setmode(GPIO.BOARD) # Use GPIO BOARD numbers
GPIO.setup(TRIGGER, GPIO.OUT) # Trigger
GPIO.output(TRIGGER, False) # Set low
GPIO.setup(ECHO, GPIO.OUT) # Echo
GPIO.output(ECHO, False)
time.sleep(0.1)
GPIO.setup(ECHO,GPIO.IN)
GPIO.add_event_detect(ECHO, GPIO.BOTH)
time.sleep(2.0)
# Main program loop # Main program loop
if len(sys.argv) > 1: if len(sys.argv) > 1:
@ -58,11 +70,7 @@ if len(sys.argv) > 1:
ECHO = int(pins[1]) ECHO = int(pins[1])
SLEEP = float(pins[2]) SLEEP = float(pins[2])
GPIO.setmode(GPIO.BOARD) # Use GPIO BOARD numbers restart()
GPIO.setup(TRIGGER, GPIO.OUT) # Trigger
GPIO.setup(ECHO, GPIO.OUT) # Echo
GPIO.output(ECHO, False)
GPIO.setup(ECHO,GPIO.IN)
# Flush stdin so we start clean # Flush stdin so we start clean
while len(select.select([sys.stdin.fileno()], [], [], 0.0)[0])>0: while len(select.select([sys.stdin.fileno()], [], [], 0.0)[0])>0:
@ -71,12 +79,13 @@ if len(sys.argv) > 1:
while True: while True:
try: try:
distance = int( Measure() + 0.5 ) distance = int( Measure() + 0.5 )
if distance != OLD: if distance != OLD and distance > 2 and distance < 400:
print(distance) print(distance)
OLD = distance OLD = distance
time.sleep(SLEEP) time.sleep(SLEEP)
except: # try to clean up on exit except Exception as e: # try to clean up on exit
print("0.0"); print(e) # Print error message on exception
GPIO.remove_event_detect(ECHO)
GPIO.cleanup(TRIGGER) GPIO.cleanup(TRIGGER)
GPIO.cleanup(ECHO) GPIO.cleanup(ECHO)
sys.exit(0) sys.exit(0)