python - 使用设定时间触发运动功能

Question

我正在制作自动狗喂食器，我希望用户能够设置预设时间，当到了这个时间时，设备将通过电机功能分配食物。

这是代码(60 行):

import RPi.GPIO as GPIO

import time

import datetime


PIN_MOTOR = 14

PIN_LIMITSENSOR = 15


GPIO.setmode(GPIO.BCM)

GPIO.setup(PIN_MOTOR, GPIO.OUT)

GPIO.setup(PIN_LIMITSENSOR, GPIO.IN, GPIO.PUD_DOWN)

GPIO.output(PIN_MOTOR, GPIO.LOW)


def doCycle():

    GPIO.output(PIN_MOTOR, GPIO.HIGH)

    while not GPIO.input(PIN_LIMITSENSOR):

        time.sleep(0.2)

    GPIO.output(PIN_MOTOR, GPIO.LOW)

    time.sleep(3)

def hour():

    return int(datetime.now().hour)


def minute():

    return int(datetime.now().minute)


option = raw_input("Would you like manual or automatic mode [manual/auto]?: ")

if option == "manual":

    while True:

        selection = str(raw_input("How big is your dog (small/medium/large/exit)?: "))

        if selection == "small":

            doCycle()

        elif selection == "medium":

            doCycle()

            doCycle()

        elif selection == "large":

            doCycle()

            doCycle()

            doCycle()

        elif selection == "exit":

            break

        else:

            print("Invalid selection")

else:
    print("Automatic mode selected.")

    schedhr = int(raw_input("Please enter the hour to schedule: "))

    schedmin = int(raw_input("Please enter the minute to schedule: "))

    iterations = 1

    selection = str(raw_input("How big is your dog (small/medium/large)?: "))

    if selection == "small":

        iterations = 1

    elif selection == "medium":

        iterations = 2

    elif selection == "large":

        iterations = 3

    print("Now scheduled to do " + str(iterations) + "cycles at "+str(schedhr)+":"+str(schedmin))

    while (hour() != schedhr) or (schedmin != minute()):

        time.sleep(1)

    for x in xrange(iterations):

        print ("Doing cycle.")

        doCycle()

这是错误消息:

Automatic mode selected.

Please enter the hour to schedule: 19

Please enter the minute to schedule: 00

How big is your dog (small/medium/large)?: small

Now scheduled to do 1cycles at 19:0

Traceback (most recent call last):

File "code4.py", line 59, in

while (hour() != schedhr) or (schedmin != minute()):

File "code4.py", line 22, in hour

return int(datetime.now().hour)

AttributeError: 'module' object has no attribute 'now'

Answer 1

datetime 模块包含同名的 datetime 类，其中 now() 是一个类方法。

因此，要调用 now() 并返回日期时间实例，您需要在第 22 行中编写:

datetime.datetime.now().hour 

或者，如果您只是从 datetime 类调用方法，通常会编写 from datetime import datetime 而不是仅导入模块名称(那么您需要不要更改第 22 行)。