基于WiFi的防盗报警Python脚本

学校图书馆有一本电子书，可以供学生阅读，但是怎么防止学生将其带出图书馆呢？我把它连上馆内的一台电脑的WiFi热点，间隔一段时间就从电脑ping这台电子书，如果ping不通，说明电子书脱离了WiFi信号范围，电脑就会响起报警声。
代码思路如下，先通过Windows上的arp命令，用设备的MAC地址获取其IP，再用ping命令检测设备是否在线，如果不在，就输出现在的时间、丢失设备IP和MAC地址，保存日志到文件，并播放报警声。
我尝试过给电子书贴RFID标签，但是RFID会受到电子书干扰，在通过门禁时无法像普通书籍一样报警。
如果各位还有什么好方法，欢迎评论！

import datetime
import sys
import time
import sched
import subprocess
from io import StringIO

try:
    import playsound
except ImportError:
    import os
    os.system("pip install playsound")
    import playsound

MY_DEVICE = ["48-e7-da-13-9e-b3"] # MAC addresses of my devices
device_ip = [""] * len(MY_DEVICE)
DETECT_DELAY = 5  # seconds
SOUND_PATH = "my_alert.mp3" # alert sound path


def detector():
    lost = []
    for i in range(len(device_ip)):
        if device_ip[i] != "":
            if subprocess.run("ping -n 2 -w 2500 " + device_ip[i], capture_output=True).returncode != 0:
                lost.append(i)

    if len(lost) > 0:
        buffer = StringIO()
        sys.stdout = buffer
        now_time = datetime.datetime.now().strftime('%Y-%m-%d %H:%M:%S')
        print()
        print(now_time)
        print("Device lost:")
        for dev_id in lost:
            print(device_ip[dev_id], "", MY_DEVICE[dev_id])
        output = buffer.getvalue()
        sys.stdout = sys.__stdout__
        print(output)
        with open("./log.txt", "a") as file:
            file.write(output)

        while True:
            playsound.playsound(SOUND_PATH)
    else:
        print("ok.")
        loop_detect()


def loop_detect():
    s = sched.scheduler(time.time, time.sleep)
    s.enter(DETECT_DELAY, 6, detector, ())
    s.run()


#get ip from its MAC address
def get_ip():
    for line in subprocess.check_output("arp -a", shell=True).decode("gbk").splitlines():
        for index in range(len(MY_DEVICE)):
            if MY_DEVICE[index] in line:
                ip = line[0:line.index(MY_DEVICE[index])].strip()
                device_ip[index] = ip

    for index in range(len(device_ip)):
        if device_ip[index] == "":
            print("Device not found in arp: ", MY_DEVICE[index])
        else:
            print("Device found in arp: ", device_ip[index], "", MY_DEVICE[index])


if __name__ == "__main__":
    get_ip()
    all_offline = True
    for ip in device_ip:
        if ip != "":
            all_offline = False
            break
    if not all_offline:
        print("Start detecting...")
        loop_detect()
    else:
        print("All offline")