import time

def get_time():
    return time.clock()

def set_start_time():
    global start_time
    start_time = get_time()

def get_time_passed():
    return get_time() - start_time 

def main():
    print("Ready?") 
    time.sleep(1)
    print("Go!")

    set_start_time()
    
    # this is measured in seconds, use 0.1 for 100 milliseconds
    
    wait_time = 1 
    while True:
        if get_time_passed() >= wait_time: 
            print("Time passed: " + str(wait_time) + " seconds!")
            set_start_time()

main()