简单模拟了定时器功能，需要的朋友可以自己改写和扩充功能。

import datetime
import winsound
import time
import random

def Timer(y, m, d, h, mu, s):
    '''参数分别为年、月、日、时、分、秒'''
    stopTime = datetime.datetime(y, m, d, h, mu, s)
    maxTime = stopTime + datetime.timedelta(minutes=1)
    while True:
        now = datetime.datetime.now()       
        if now >= stopTime:
            if now > maxTime:
                print('时间已过1分钟，请重新设置时间')
                break
            else:
                #每次闹铃声音频率不同
                freq = random.randint(400, 1000)
                winsound.Beep(freq, 2000)
                time.sleep(2)
        else:
            time.sleep(1)
            delta = stopTime - now
            print('剩余：', delta.seconds, '秒')

Timer(2017, 2, 8, 20, 31, 0)