Automated Mail Notifier

Our thoughts regarding physical mail and posts is that it is diminishing over time. But, still some of our important documents are still sent through physical mail.
Most of have a post box out of our house, and some live in an apartment and that also have an array of post boxes of houses.
What if we don't check our mail box regularly?
A gentlemen was not a big fan of Physical mail, and one day a tax bill was sent to his home and it was rested in the post box for about a month. This man was not aware of this and resulted him to pay the bill immediately with a penalty.
If he checked the mail box he could have saved some amount of his money and his temper.
That gentlemen wanted to have a solution for this, but he doesn't like to check that post box every time.
So, if we have an Arduino we have the solution.

This system notifies the user whenever there is a mail and hence avoiding the need to check for mail frequently.
This project is based on RF module (RF Transmitter and Receiver) and a light sensor.
For this project we use two Arduino boards to create two circuits. One is for the transmitter and the other is for the receiver.
It may sound some what complicated and costly but, it is easy and we have used our own Arduino made using ATmega328P.

Components Required - 

For the Transmitter

• Arduino Uno
• RF Transmitter module (434MHz or 315MHz)
• Photo Resistor 
• 15KΩ Resistor
• Battery

For the Receiver 

• Arduino Uno
• RF Receiver module (434MHz or 315MHz)
• Power supply

Transmitter

For the transmitter we use Arduino UNO, and the RF transmitter module and a photo resistor. The transmitter module used in this project consist of 4 pins.

LDR which is the photo resistor used is connected to Analog pin of the Arduino board.

In order to detect small change in resistance a resistor is used with the LDR in potential divider method.

Receiver 

For the receiver Arduino UNO and the RF receiver module.

The main aim of this project is to notify the user with a message whenever the user receives a mail in their mailbox. As the main sensor module we have used LDR to detect the mail in the mail box. This can differentiate the two scenarios which is open door and close door. 

Arduino compares this value with a threshold value in the program. 

• If the sensor value is less than the threshold it means that the door is not opened and is no mail yet, and in this case Arduino sends a message "No Mail" via the transmitter and the receiver receives this and display in serial monitor. 
• Similarly if the value is greater than the threshold value it means that the door is opened and a mail inserted, so the Arduino sends a Mail arrived message via transmitter and the receiver reveives this and display in serial monitor.
• We hope to develop this into a LCD display

We are using a Buzzer system to alert the user, and we are trying to include a GSM module into this system so that the user will get a message to his/her mobile where ever they go.

This is a project for a great gentlemen and during our research phase we were influenced from a good project in Electronichub, that was not enough in this scenario so we developed that a bit further.