#!/usr/bin/env python2

import serial
import time

s = serial.Serial("/dev/ttyACM0", 9600)

while True:
    c = s.read()
    if c == ".":
        t = time.time()
        ms = int(t * 1000) % 1000

        print "{0}.{1:03} .".format(time.strftime("%H:%M:%S"), ms)