• 環保尖兵：空氣品質守門員

簡易物聮網系統實作(2)

• 講義

• 本單元重點在於引導學生使用Python程式將教師架設的客製化網站爬取資料，並依資料內容作相對應的輸出反應。

  #!/usr/bin/python
  #+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  #|R|a|s|p|b|e|r|r|y|P|i|.|c|o|m|.|t|w|
  #+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  # Copyright (c) 2016, raspberrypi.com.tw
  # All rights reserved.
  # Use of this source code is governed by a BSD-style license that can be
  # found in the LICENSE file.
  #
  # led_blink.py
  # Blinking led without warning (Add try/except)
  #
  # Author : sosorry
  # Date   : 06/22/2014
  
  import RPi.GPIO as GPIO 
  import time
  import requests
  from bs4 import BeautifulSoup
  
  LED_PIN = 12	
  GPIO.setmode(GPIO.BOARD)
  GPIO.setup(LED_PIN, GPIO.OUT)
  url = "http://127.0.0.1:8000"
  r = requests.get(url)
  web_content = r.text
  
   
  soup = BeautifulSoup(web_content, 'html.parser')
  content = soup.find_all('div', class_="value")
  values = [int(e.text) for e in content]
  print(values[0])
  
  try:
      while values[0]>30:
          print("LED is on")
          GPIO.output(LED_PIN, GPIO.HIGH)
          time.sleep(1)
  
          print("LED is off")
          GPIO.output(LED_PIN, GPIO.LOW)
          time.sleep(1)
  
  except KeyboardInterrupt:
      print("Exception: KeyboardInterrupt")
      
  finally:
      GPIO.cleanup()