You’ve Got Mail?

Life is full of tough decisions, such as deciding whether you want to go to the end of the drive to check if the mail has arrived. These questions are made even more arduous in the winter months, but [Catpin] has a solution. The Mail Box Alert uses an Electric Imp, a solar panel and a proximity sensor to let you know if you’ve got mail.

It’s a neat build, with the brains provided by that Electric Imp which handles most of the heavy lifting. This wakes up every five minutes and checks whether the status of a small proximity sensor has changed. If it has, it pings a website. The unit sits at the bottom of the postbox, so if your friendly neighborhood post person has put in any letters, it will have changed. The Imp is powered by a small battery, which is in turn charged by a solar panel. That means that it doesn’t require any power cables or other wiring, as long as it is in the range of WiFi. With the addition of a 15-hours overnight deep sleep, [Catpin] found that the whole thing could be run from a couple of 18650 LiPo batteries.

Perhaps the most interesting part of the writeup was discussing the problems that he found with the build, such as the fact that a LiPo battery won’t perform that well in a Wisconsin winter. So, this was replaced with a Lithium Iron Phosphate battery that should be a bit more tolerant of the chill. There is also a writeup on how to create the same project using an ESP8266 if required.

24 thoughts on “You’ve Got Mail?

  1. Nice, well-developed project! We have it a bit easier with the European style mailboxes that have a slot for throwing in mail and a locked little door to remove it. I simply use two magnet switches to trigger “mail in” and “mail removed”. But my in-laws have an American style mailbox, perhaps that needs a notifier :-)

    1. You got a write up about that?
      I’m looking to dos something similar.
      All the hardware is available (ESP8266 and reed switches or the like), but I’m wondering how to integrate it in Domoticz,

    1. Bob, that was a nice build. I wanted a text message so I know from ‘anywhere’ whether or not there is mail in the box. Also, I no longer use the red flag. It’s really sad to have to say this, but that flag is a signal to thieves that there is mail in the box. The mailbox itself is not the star in this project. It’s the use of a WiFi microcontroller that is solar powered, in an extreme climate that is the point of the build. It could just as well be any type of data logging unit, or signaling system, etc.

    1. The little red flag is for the mailman to know if there is *outgoing* mail, that you wish to send, by placing it in your own mailbox, and raising the flag so they know to stop and collect the outgoing mail.

      You know, back when that was a thing people did… or probably still do, in some places, but I’ve never seen it.

      1. Interesting. Our convention was the flag indicated there was mail in the box, period. Maybe our local postie was more helpful than most, then. If you put a dollar bill in the mailbox with un-stamped outgoing mail they also would even apply a stamp and leave the change in the mailbox. Halcyon days, I suppose.

  2. All you need is a smartphone put into your mailbox and camera appl ready
    forget arduino inventions
    Smartphone discovering light, opening of a mailbox, can call you, transmitting video remotely

    1. My dad mounted a length of dowel to his mailbox, it pivots from the back of the box and rests on a screw in the mailbox door. when the box is opened the dowel falls, costs less than a buck, doesn’t look sketchy, and is immune to the weather conditions, well, I guess it could ice up, but that would probably be an easy enough problem to circumnavigate.

  3. I am the creator of this mailbox project. First of all, I’m in Minnesota, not Wisconsin, but the weather is the same. I thought of a limit switch, but I did not want any delivery person to see anything in the mailbox. Switches, wires, etc might seem suspicious. I guess they see the solar panels or the plastic box on the back, but nothing obvious inside the box. One main point of this project, and the reason I’ve posted it, is to help out beginners (in electronics), and people who are trying to do battery projects in cold climates. It’s a challenge to build something that withstands a location that has -40F to +100F temperatures. So please look at this project as a learning lesson, especially people who wish to get into microcontrollers.

  4. Could probably be even more power conserving using an ESP8266/32 configured to go into deep sleep mode. Use a PIR sensor in the mailbox to trigger the reset pin on the ESP so it reboots, runs a sequence of commands to ping your web service, then go back into deep sleep till the next time the PIR sensor trips the reset pin. Such a setup would probably run off a few alkaline batteries for months. Something like this example code, replacing the push button with the PIR would probably do

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