From e9624b5f6e0bf40ab7d368ea162e251e53eeb3aa Mon Sep 17 00:00:00 2001
From: Ryan Tresman <tresmanr@cardiff.ac.uk>
Date: Sun, 4 Aug 2024 15:47:12 +0000
Subject: [PATCH] Upload New File
---
parking_sensor.py | 127 ++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 127 insertions(+)
create mode 100644 parking_sensor.py
diff --git a/parking_sensor.py b/parking_sensor.py
new file mode 100644
index 0000000..66d7909
--- /dev/null
+++ b/parking_sensor.py
@@ -0,0 +1,127 @@
+import time
+import datetime
+import sys
+import os
+import grovepi
+import math
+import json
+import traceback
+import subprocess
+import multiprocessing as mp
+from video_server import runVideo
+
+
+ranger = 4
+buzzer = 6
+
+alertThreshold = 100
+midThreshold = 50
+warningThreshold = 20
+
+grovepi.pinMode(ranger, "INPUT")
+grovepi.pinMode(buzzer, "OUTPUT")
+
+
+startBuzz = None
+buzzDelay = None
+buzzOn = False
+LCDUpdated = datetime.datetime.now().timestamp()
+buzzDuration = 0.05
+
+
+#Read data from ultrasonic ranger
+def readDistance():
+ try:
+ distance = grovepi.ultrasonicRead(ranger)
+ return distance
+ except:
+ return None
+
+
+def setBuzzer(buzzOn):
+ buzzing = grovepi.digitalRead(buzzer)
+ # Read buzzer state, if buzz is needed and not buzzing already, then start buzzing. Turn off if buzz state is not wanted.
+ if buzzOn:
+ if not buzzing:
+ grovepi.digitalWrite(buzzer, 1)
+ buzzing = True
+ else:
+ if buzzing:
+ grovepi.digitalWrite(buzzer, 0)
+ buzzing = False
+
+#Wrapper for the buzzer
+def buzzerWrapper(distance):
+ global startBuzz, buzzDelay, buzzOn, buzzDuration
+ #Only start buzzer if in alert threshold
+ if distance and distance <= alertThreshold:
+ #Delay is equal to inverse of distance, with a minimum value
+ delay = (distance-warningThreshold)/100
+ delay = max(0.03, delay)
+ #If buzzer has not started, start it and set time.
+ if startBuzz is None:
+ setBuzzer(True)
+ startBuzz = datetime.datetime.now().timestamp()
+ #If not in delay, but are buzzing, keep buzzing until buzz duration has elapsed.
+ elif not buzzDelay and startBuzz and datetime.datetime.now().timestamp() - startBuzz > buzzDuration:
+ if distance > warningThreshold:
+ buzzDelay = datetime.datetime.now().timestamp()
+ setBuzzer(False)
+ #If in delay, delay until the pause between delays has elapsed.
+ elif buzzDelay and datetime.datetime.now().timestamp() - buzzDelay > delay:
+ buzzDelay = None
+ startBuzz = None
+
+ else:
+ #If not in alert threshold, make sure buzzer is off.
+ setBuzzer(False)
+
+def resetSystem():
+ #Reset the system to off state
+ grovepi.digitalWrite(buzzer, 0)
+
+
+def videoProcess():
+ queue = mp.Queue()
+ return mp.Process(target=runVideo, args=(queue,)), queue
+
+
+def exceptHandler(process, queue):
+ #Force system quit on exception
+ if queue:
+ queue.put('terminate')
+ time.sleep(1)
+ if process:
+ process.terminate()
+ process.join()
+ resetSystem()
+ exit()
+
+if __name__ == '__main__':
+ process = None
+ try:
+ #Start the video server
+ process, queue = videoProcess()
+ process.start()
+
+ #Initialise multiprocessing dictionary
+ manager = mp.Manager()
+ d = manager.dict()
+ d['warningThreshold'] = warningThreshold
+ d['midThreshold'] = midThreshold
+ d['alertThreshold'] = alertThreshold
+
+ #First read of distance is None
+ readDistance()
+ while True:
+ #Event loop
+ distance = readDistance()
+ d['distance'] = distance
+ queue.put(d)
+ buzzerWrapper(distance)
+ except KeyboardInterrupt:
+ exceptHandler(process, queue)
+ except Exception as e:
+ print(e)
+ exceptHandler(process, queue)
+
--
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