doorbell sensor to send MQTT messages if it rings

doorbell.py

import wifi
import network
import ubinascii
from time import sleep, sleep_ms, time
from machine import ADC, unique_id
from umqtt.simple import MQTTClient
from umqtt.simple import MQTTException

server = '192.168.2.4'
CLIENT_ID = ubinascii.hexlify(unique_id())
topic = b'cmnd/doors/doorbell/pressed'
db_signal = ADC(0)


def reconnect(hostname):
    wifi.do_disconnect()
    sleep(1)
    wifi.do_connect(hostname)
    main(hostname)


def main(hostname):
    c = MQTTClient(CLIENT_ID, server, keepalive=1800)
    try:
        c.connect()
        print('Connected to MQTT.')
        c.publish(b'stat/doorbell/state', 'started')
        c.disconnect()
    except (OSError, MQTTException, IndexError):
        reconnect(hostname)

    last_msg = 0.0
    # sta_if = network.WLAN(network.STA_IF)
    while True:
        #print(sta_if.isconnected())
        if db_signal.read() > 820:  # test and change that value
            if time() - last_msg > 5:
                try:
                    last_msg = time()
                    c.connect()
                    c.publish(topic, 'True')
                    c.disconnect()
                except (OSError, MQTTException, IndexError):
                    reconnect(hostname)
                print('Doorbell\'d')
        #sleep_ms(10)

reading average of last minute and detecting changes to that might be better, for the voltage drop of the battery?