Time issue in Python

Question

My program is working with input() from user. I want to print "hey,are you there?" when the user hasn't written anything in 5 seconds. For example, the user writes something, and stops typing. If the user waits more than 5 seconds, then I want to print "hey,are you there?". So far I tried this:

while True:
    start=time.time()
    x=input("enter something")
    end=time.time()
    dif=end-start
    if 5<dif:
        print("hey are you there?")

It didn't work as I expected, because it waits for the user. It's writing "hey are you there?" after the user wrote something. But I expect that when the user doesn't type anything, it also means x==False, I want to warn the user.

Update I tried this one:

import msvcrt
import time

time1 = 0

print('enter something: ')

while not msvcrt.kbhit():
    time.sleep(1)
    time1 +=1
    if time1 == 5:
        print("hey are you there?")

while msvcrt.kbhit():
    x = input()

It didn't work either. It printed "hey are you there?" after 5 seconds even x==True. So far no solution, hope I explained what I need.

Answer 1

Seems like this works, but I'm using python 2.7:

    import threading, time

    class ValueGetter(object):
        def __init__(self, wait_time_sec = 5.0):
            self.stop_flag = True
            self.wait_time_sec = wait_time_sec

        def get_value(self):
            self.stop_flag = False
            p = threading.Thread(target=self.print_uthere)
            p.start()
            retval = raw_input('enter something:\n')
            self.stop_flag = True
            p.join()
            return retval

        def print_uthere(self):
            tprint = tnow = time.clock()
            while not self.stop_flag:
                if tnow > (tprint + self.wait_time_sec):
                    print 'Are you there???'
                    tprint = time.clock()
                time.sleep(0.01)
                tnow = time.clock()

    v = ValueGetter()
    print v.get_value()

Here is a modified version that will reset the 5 sec timer whenever they enter a key. Windows only though.

import threading, time, msvcrt, sys

class ValueGetter(object):
    def __init__(self, wait_time_sec = 5.0):
        self.stop_flag = True
        self.wait_time_sec = wait_time_sec
        self.tprint = self.tnow = time.clock()

    def get_value(self):
        self.stop_flag = False
        p = threading.Thread(target=self.print_uthere)
        p.start()
        print 'enter something:'
        retval = ''
        ch = ''
        while not ch == '\r':
            retval += ch
            ch = msvcrt.getch()
            sys.stdout.write(ch)
            self.tprint = time.clock()
        print
        self.stop_flag = True
        p.join()
        return retval

    def print_uthere(self):
        self.tprint = self.tnow = time.clock()
        while not self.stop_flag:
            if self.tnow > (self.tprint + self.wait_time_sec):
                print 'Are you there???'
                self.tprint = time.clock()
            time.sleep(0.01)
            self.tnow = time.clock()

v = ValueGetter()
print v.get_value()