Главная > Новости > mailbox alarm

mailbox alarm

The device uses a photoresistor to detect the light levels in the mailbox alarm. When the light is above a certain threshold, the Arduino knows the mailbox is open. There is a red button on the front of the device that you press to arm it. After you press the button, the next time the mailbox is opened, presumably by the mailman, you will get a text. It will not send you a text again until you have armed it again. This ensures that you don’t get a text every time you open the mailbox. Every time you pick up your mail, arm the mailbox phone alert and enjoy instant mail notification.

Preliminary advice: Inform your mailman of your contraption so that he does not think you have a planted a bomb in your mailbox and use a non-metal mailbox for good cellular connection. We’d reiterate that last bit too—might want to let your mail carrier know there’s a sensor in the mailbox so they don’t freak out and you find a bomb squad about to detonate your mailbox.

Beyond that though, even if you’re not obsessive about finding out when your mail arrives, a tool like this could be a good way to find out if someone’s snooping in your mailbox that’s not the mailman, and combined with a small camera, you may even be able to catch mail thieves in the act. The possibilities only go up from here. Hit the link below to see how the whole project was made, and what you’ll need to make one yourself. For the first design, I used the guts out of a pair of walkie-talkies in the receiver and sender. To differentiate between the two signals (mailbox and paperbox), I used DTMF (dual-tone, multi-frequency) encoder/decoder ICs. These were the ICs used in telephones that would generate and receive the tones used with touch-tone phones. So, for example, when the paper came, a switch closed, and actuated the walkie-talkie with the same tone as when pressing the «2» button on the phone. When the mail switch closed, it would send the tone equivalent to pressing the «3» button on the phone. Meanwhile, the receiver in the house would encode these signals and turn on the appropriate LED.

For actuation switches, I used two different approaches. On the mailbox, I mounted a mercury switch on the door, so that when it was opened, the contacts would close and that would power up the transmitter and decoder. On the paperbox, there was a swinging door suspended from the top. I mounted a magnetic burgler alarm sensor to the box, and a magnet in the door. An advantage of this approach is that wires don’t need to move when the door swings open and shut.