arp-log.py

from tplinkarpmon import TPLinkARPMon
from datetime import datetime
from time import sleep
import sys

tpl = TPLinkARPMon('router-address', 'admin-username', 'admin-password')
DELAY = 60
prev_devices = set()

print('Initialized ARP monitoring util at {}'.format(datetime.now()))

while True:
    try:
        devices = tpl.connected_devices()
        device_macs = []

        for d in devices:
            device_macs.append(d[0])

        curr_devices = set(device_macs)
        execution_time = datetime.now()
        devices_joining = curr_devices - prev_devices
        devices_exiting = prev_devices - curr_devices
        prev_devices = curr_devices

        if len(devices_joining) > 0:
            print('{} - {} device(s) active, {} device(s) joining: {}'.format(execution_time, len(curr_devices), len(devices_joining), devices_joining))
        if len(devices_exiting) > 0:
            print('{} - {} device(s) active, {} device(s) exiting: {}'.format(execution_time, len(curr_devices), len(devices_exiting), devices_exiting))

        sleep(DELAY)

    except Exception as e:
        print(e)
        sys.exit()