Mail Detector

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  Component schematic of the device (sans voltage sources)

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  Physical device configuration

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  Device in a mailbox-sized compartment

Inspiration

Ring doorbells are used by many homeowners to receive package delivery alerts, so what if there was a similar device for mail detection? Many important alerts are still delivered via mail, and the added convenience of delivery alerts benefits residents living in apartments with centralized mailboxes, homeowners with several properties, and individuals living in areas prone to mail theft.

Function

Whenever mail gets delivered to the mailbox, an alert gets sent to the homeowner via Discord. The homeowner has the option of turning off the device when retrieving their mail, as to prevent unnecessary alerts. If a thief were to steal mailbox contents, an alert will also be sent to the homeowner.

Construction

The device consists of an HC-SR04 distance sensor and Raspberry Pi Pico W housed on a breadboard. Both components are powered by 4 AA batteries which supply voltage to the breadboard via a breadboard power supply. This device is placed at the entrance of a mailbox, and on startup, the Raspberry Pi executes a MicroPython script that monitors the readings from the distance sensor. When an object is detected within 5 centimeters of the distance sensor, an alert gets sent to the homeowner via Discord.

Challenges

Interfacing the Raspberry Pi with Discord proved to be the most challenging aspect of the project. However, with repeated trial and error, a working MicroPython workflow was programmed. Lengthy hardware and software debugging sessions led to the configuration of the final product.

Learning Experiences

This project provided insight onto the hardware and software configurations of IoT devices. By the end of development, a better knowledge of IoT networks and troubleshooting was gained. The project provided insight towards optimizing such workflows in the future.

What's next for Mail Detector

The network backend of the mail detector device can be further expanded with various cloud solutions, such as a database to log mail deliveries, and remote device control. Additionally, the hardware can be compacted into a smaller build that takes up less space, paving the way for a feasible device for everyday use.

Built With

• breadboard
• distance-sensor
• micropython
• raspberry-pi-pico-w