Making an alert device can help you get mailbox notification so that instead of frequently going to the mailbox from the comfort of your ac room to check to see if the mail has come or not. It is achieved by an alert to signal received at your home wirelessly. Few key features are required to be looked into while choosing this type of mail alert system for your mailbox, that includes wireless range, alert type and sensor type.The very item commercially available in Home Depot are far more expensive compared to this DIY unit that can be easily made by anyone with little electrical knowledge and by not engaging any Handyman.

Step 1: Wireless Range

The range of a mailbox alert system should cover the farthest distance from the transmitting the device housed in the mailbox and the receiver unit at the home. Therefore we have chosen a distance of 100 meters to be most effective for many houses and be cost effective too by using a of low cost transmitter and receiver pair from Ebay—Titled product on Ebay is

“AC 110V 10A relay 1CH wireless Smart Remote Remote Switch Transmitter+Receiver” at http://www.ebay.com/itm/AC-110V-10A-relay-1CH-wir...

The remote to be used for the same has only one push button for on and off alternatively . This will help to use contact points from a low cost mercury switch (readily available from ebay at less than a dollar) soldered to the push button points of the remote.The receiver that directly operates from 110 v mains has a relay that can be used for any load.

Step 2: Alert Type

The system uses an alert to notify you when your mail has arrived, by buzzers, bells or a simple mains lamp. The alert load is wired as per the diagram seen here, arranged for the receiver board located in the house duly plugged into the mains supply always.Whenever the transmitter sends a signal the relay operates as long as the door is kept opened by the mail carrier after which the relay drops so also the load.The flag use however on the mailbox requires manual operation.

Step 3: Sensor Arrangement

This simple wireless mail alert system works by sending a signal from the transmitter to the receiver relay. A tilt sensor comprising of a mercury switch is placed inside the mailbox in pin side in upright position, so that when the box is opened, the mercury switch closes and thus a signal from the sensor is sent to the transmitter push button (duly wired by opening it and soldering the points ) which in turn wirelessly sends the signal to the receiver, so you are alerted of the mail arrival in the home where the receiver is located. Once mailbox door is opened, the mercury switch goes horizontal because of the tilt that activates the push button once as ON and while it is closed after loading the mails, the mercury switch sends the OFF signal to the transmitter which in turn switches off the relay in the home receiver. The transmitter is housed in the mailbox with its small telescopic antenna exposed outside the mailbox for a good range coverage.As it operates only for a very small duration the battery life is more than couple of years.