Mailbox Sensor

Welcome to Mnux's website. This is my personal blog about stuff.

IoT Mailbox sensor

A mailbox sensor which sends me a notification through Home Assistant when I get mail.

This bracket securely mounts the IOT board to a box without adding a lot of height so the push button doesn't collide with the battery.

Inner workings

Tilt switch

This is a SW-520D ball tilt switch, it wakes up the ESP-8266 when the mailbox lid is open.

Temp + humidity

While a tempature sensor inside of a mailbox has a debatable purpose. However it is pretty interesting to know at what tempatures are the delivery people working. (its just a 1€ part anyway)

Sensor power switch

This being a battery powered sensor it needs to save as much energy as possible. The mosfet power switch turns on the sensory only for the time they are needed.

Sleep fix resistor

For some reason my ESP8266 modules suffer from a problem called "zoombie mode" where after waking them up from deep sleep they fail to boot. Thankfully this can be fixed by running a pullup resistor from GPIO 7.

ESPHome and Home Assistant configuration

In home assistant i setup an automation setup which sends me a notification containing the current temperature and battery voltage after it detects that the sensor woke up.
Alongside with the notification I also get information about the battery voltage and temperature.

Published 9.12. 2024

Silly badges :3