树莓派+LED红绿灯（2020-09-01）

用树莓派，检测CPU占用率，并用红绿灯展示出来。

#!/usr/bin/env python
# to use with Pi Traffic Light
 
import RPi.GPIO as GPIO
import psutil  #导入测试CPU使用率的库
 
GREEN = 6 #绿灯接6号
YELLOW = 13 #黄灯接13号
RED = 16  #红灯接16号
 
# Pin Setup:
GPIO.setmode(GPIO.BCM)   # Broadcom pin-numbering scheme.
GPIO.setwarnings(False)    #设置忽略警告
GPIO.setup(GREEN, GPIO.OUT)  #设置输出模式
GPIO.setup(YELLOW, GPIO.OUT)
GPIO.setup(RED, GPIO.OUT)

try:
   while (1):
      cpu_pc = psutil.cpu_percent(interval=2)
      print('CPU:    '+str(cpu_pc))
      if cpu_pc <= 3:     #如果CPU占用率小于3，亮绿灯，黄和红灭
         GPIO.output(RED, False)
         GPIO.output(YELLOW, False)
         GPIO.output(GREEN, True)
      if 3 < cpu_pc < 6:
         GPIO.output(GREEN, False)
         GPIO.output(RED, False)
         GPIO.output(YELLOW, True)
      if cpu_pc >=6 :
         GPIO.output(GREEN, False)
         GPIO.output(YELLOW, False)
         GPIO.output(RED, True)
except KeyboardInterrupt:
    print('Good bye')
    GPIO.output(GREEN, False)
    GPIO.output(YELLOW, False)
    GPIO.output(RED, False)