Binary Translator Python

import time
import sys
time.sleep(.5)
def typwrt(string):
    for x in string:
        sys.stdout.write(x)
        sys.stdout.flush()
        time.sleep(.01)
typwrt('Welcome to the Decimal and Binary Translator!')
time.sleep(1)
print ''
typwrt('By Kevin Shannon')
while True:
    time.sleep(1)
    print '\n'
    typwrt('Type "db" for decimal to binary, Type "bd" for binary to decimal:')
    dbbd = raw_input()
    digits = 1
    stop = False
    bi = []
    if dbbd == "db":
        typwrt("input a decimal number:")
        number = raw_input()
        """makes sure you enter something and it is a number"""
        if len(number) > 0 and number.isdigit():
            num = int(number)
            """unless inbetween 2 2**x numbers change number until you are between them"""
            while stop == False:
                if num == 0:
                    stop = True
                elif num >= 2**(digits - 1) and num < 2**digits:
                    stop = True
                else:
                    digits += 1
            while digits > 0:
                sub = 2**(digits - 1)
                if num - sub >= 0:
                    bi.append(1)
                    digits -= 1
                    num -= sub
                else:
                    bi.append(0)
                    digits -= 1
            typwrt(str(bi).replace(',','').replace(' ', '').strip('[]'))
        else:
            typwrt("That was not a decimal number.")
    elif dbbd == "bd":
        typwrt("input a binary number:")
        number = raw_input()
        total = 0
        """makes sure you enter something and it is a number"""
        if len(number) > 0 and number.isdigit():
            digits = len(number)
            num = int(number)
            """turns string into list of each 1 and 0"""
            bi = [int(d) for d in str(num)]
            """ for each number it sees if its a 1 or 0 and adds all them up"""
            for number in bi:
                if stop == False:
                    if number == 1:
                        total += 2 ** (digits - 1)
                        digits -= 1
                    elif number == 0:
                        digits -= 1
                    else:
                        stop = True
        else:
            stop = True
        if stop == True:
            typwrt("That was not a binary number.")
        else:
            typwrt(str(total))
    else:
        typwrt("You didn't type either db or bd!")