Mailbox Notifier Texts When The Letter Carrier Arrives


[Felix Rusu’s] mailbox is on the other side of the street and he’s got a pretty big front yard. This means checking for mail is not just a pop your head out of the door type of activity. This becomes especially noticeable during the winter months when he has to bundle up and trudge through the snow to see if his letter carrier has been there yet. But he’s made pointless trips a thing of the past by building a notifier that monitors the mailbox for him.

He’s using a Moteino, which is an Arduino clone of his own making. It’s tiny and features an RF module on the underside of the board which takes care of communicating with a base station inside the house. The module seen above rolls the microcontroller board up along with a 9V battery and a hall effect sensor which can tell if the mailbox door is open or closed. When the Arduino detects a change to that sensor it pushes some data back to the base station which then relays the info to a computer or Raspberry Pi in order to send him a text message. All of this is shown off in the video after the break.

71 thoughts on “Mailbox Notifier Texts When The Letter Carrier Arrives

  1. I was thinking about trying something similar, until a grandfather down the street showed me the “wireless driveway sensor” he bought for 9.95 and put it in his mailbox. Everytime the box is opened it chimes. He had me beat.

    1. Yup, this project is way overkill as the same function can be achieved with 1/10 the cost and complexity. Take it as a chance to study the platform, not as a well engineered implementation of the idea.

      1. My mailman’s tried to excuse himself before. I simply wrote him a kind note to just deliver it next time.
        …Oh, and I wrote on the back of a “PO box application”

    1. How far away is his house? My mailbox is 150 feet away, wondering how to get a power miserly rf signal from there to here.

      And yes, Federal PMITA prison as soon as the substitute mail carrier flips her shit.

        1. No it’s not your mailbox even if you bought & installed it, the box belongs belongs to the USPS. Kinda cray to blow up an installed mail box seeing you are going to have to install new on to get the mail. Your money & time do whatever turns your crank. :)

    2. Well, there’s have to be intent to harm in order for you to go to “Ram in the ass” prison. A simple notifier may be misunderstood by the postman, but it won’t get you thrown in prison.

      The fact that some of you have a kee-jerk reaction like this means you are all so afraid of the government that you’ve lost the American spirit of innovation. :-(

  2. Don’t they have flags on the sides of mailboxes anymore?

    I grew up in the countryside of Canada and we never had this problem. The norm was for the letter carrier to raise the flag that was affixed to the side of the mailbox when he/she put mail in there. If we had mail to send we’d put it in the box and raise the flag so they would know to stop and pick it up.

    When did things change? BTW, I moved to the city about 15 years ago.

    1. I’ve never had a mailbox (military and apartment living), but I do know what you’re talking about. That really would be the most simplest solution. If I recall correctly, they’re usually bright red flags, too!

    2. The idea here is to alert you if the standard red flag is to alert the carrier that you have mail you want them to pick up. The do make and yellow flag to add to the box that will automatically pop up when the carrier opens the box to deliver mail.

  3. I know this is a hack, but I wouldn’t want my mailman getting curious about a taped up little package on the lid of my mailbox. He might think it’s a bomb or something stupid like that. Maybe this just says something about the community around me, though. :-)

    I would have stuck the Arduino board and battery all the way into the back of the mailbox, placed the hall effect sensor alone on the lid, and run the wires along the edges of the interior of the mailbox to keep it neat.

  4. I still don’t get why so many people use 9V batteries. They have low energy/volume and energy/price ratio, deliver a low maximum current and are rather large. On top of that you burn off about a third of the energy with a 5V regulator in most projects.

    I usually use a scavenged or cheaply bought Li-Ion and a $2 booster circuit if i need 5V. Most µC projects will happily run straight off a Li-Ion though.

    Almost always when a laptop battery pack is “dead” to the laptop, at least 2/3 of the batteries are fine, just a little run down. The larges difference is that they will have a slightly higher than usual internal resistance but they work fine in low current applications. Here is a link to a neat Li* protection circuit combined with a 5V booster in a very small package:

    1. Most of the time it’s entirely because of the voltage, and because they are cheaply available. I agree about using a Li-Ion for most things, but when you can get the batteries so easily they do end up attractive. Personally I’d love a booster that’d let me drain off some D-Cells to power things at 3.3v for a very long time.

    2. Quiescent current. Let’s say I have a microcontroller that uses 2mA when operating and spends most of it’s time in sleep mode, where is consumes 8uA. It is active for a grand total of 10 seconds per day. The LDO has a quiescent current draw of 2uA. That is about 1 Coulomb per day of charge.

      Try finding a switchmode converter that uses <10uA of quiescent current. If you application spends most of it's time in sleep mode, then this is the factor that will dominate.

  5. My grandmother had something liek this in the 80’s, it was tied down to the door and actuated by a(n internal) mercury switch. Obviously it wasn’t powered by a microcontroller more powerful than the world had seen at the time, but Inside the receiver would play “She’ll be Comin’ ‘Round the Mountain” when it tripped and a light would stay on until you pressed a button to reset it.

  6. Am I the only one that still knows what the flag on the mailbox is used for? If the flag is raised, the postman knows “Hey, there is something in here for me.”. Once he picks up the mail, he drops the flag. If there is mail to be picked up by the owner, the flag stays up.

    1. that would only work if and when you have to leave mail. aka you would have to leave mail every single day for it to work. which would mean you would be at the mail box every single day. which would mean you have no use for this

    2. I don’t know where you’re from but in my part of the US, the flag is only used to tell the mail carrier to take the mail in the box. It’s never used to alert the owner that there is new mail.

    1. Convenience is something most people appreciate. No car is longer than an estate driveway, but people still get central locking simply because it’s more convenient. Another example is the Internet – it allows one to sling personal insults at people from the convenience of one’s own home, without the hassle of doing it in person. Sorry, I need more coffee :/

    2. I dunno. Last place I lived it was 300 yards to the mailbox. It was a communal setup with around 30 boxes. No way I am walking through the snow just for junkmail. It would take twenty minutes and I would still have to cut through a couple yards.

      I checked the mail once a week at best.

    1. I live in New England where ball-bat mailbox attacks are common. Solution? People here have mounted large wooden board about 2′ by 4′ on traffic side of mailbox. They put their address number on the top. It seems to work as the idiots look for easy targets and this configuration presents a much harder target.

  7. As nifty as this is (and I would really like to make something like it), I have to agree that unless it’s packaged in a much less dodgy-looking manner, this is probably a good way to get your mail box blown up by EOD and find yourself in prison.

    1. Do Americans really get sent to jail with no due process? Surely any decent forensics guys are gonna figure out pretty sharpish that there was no bomb. Also why would you blow up your own mailbox?

      1. “Due process” just means that they have a few hearings proving that you put something that looked scary to someone else in your mailbox. Things have been very weird in this country for the last 12 years, and it’s scary that weird is now accepted as normal.

      2. No they do not. Mainly you are seeing people that are into posting hyperbola to push a political agenda. Yes the cops may be called and you would be asked what the heck. At worst you would be asked to not use it but probably they would just say okay. Most of the weird stuff people talk about is just in there head or they take a poorly handled case and make it look like the norm.

        1. I left out that no one would probably do anything or care and I would also point out the all the FUD slingers…. This guy lives in the US and he has not gone to jail and nothing happened to him.

    1. Reed switch as well. Have it hooked to a simple RF remote like a key fob and hook the receiver up to your PC, Maybe tie it to a line of a serial port or printer port. Worse comes to worse a cheap USB gamepad.

  8. I keep getting excited when I see mail alert projects, but leave sad when it looks to be either too complex, or too simple for my purposes.
    I’d really like a way for a cheap remote switch (door bell, driveway alarm, home alarm window trigger, whatever) to trigger an Android phone (possibly with Tasker help) to take a photo, several photos, or video. (May sound paranoid, but I’m looking at possible stalker issues in my near future, want this, and other monitoring equipment in place before problems begin)
    I’m confident in setting up the entire thing with the exception of where the remote switch receiver tells the phone it has been tripped. They always seem to involve Arduinos, Raspberry Pis or other such items that I’m not quite ready to tinker with yet time-wise :/
    If anyone has any ideas on that part…

  9. I would have used a few different solutions.

    1) just a simple push button under the front of the mailbox that is engaged when the door is open (think of where it hinges).

    2) an optical sensor in the back that detects sunlight (or reflection off the front of the box)

    both of these would probably be less suspicious then the taped up mess in the front.

    1. I like the idea of the driveway sensor – I wonder if it would work if it were stuck on the back of the mailbox to sense when the door is lowered? I know I could hack the circuit to work like that but it would be nice if it would work out of the box.

  10. I like it but how about a jumbo red flasher LED from Radio Shack wired in series with a limiting resistor, 9 v alkaline battery, and a burglar alarm normally closed reed switch (closes when magnet removed) and it’s companion magnet (also available at RS)? The LED would be mounted on top of box (via a drilled hole). No suspicious boxes to freak out the temporary replacement USPS carrier covering that day. And if you can’t see it flashing from that distance either use your binoculars or replace the LED with a laser pointer aimed at your front door. The laser pointer would not need a 9v battery as they typically run on 3 1,5v mercury cells (4.5 volts total). To eliminate “door left open” condition (draining the battery) put elastic band(s) on the door. However, this certainly will piss off your carrier as (s)he will have to hold the door down while loading and the band(s) will only get in the way..

    I like the driveway alarm because Harbor Freight sells them for $12 bucks (USD). However it requires 9v battery in sender, and C-cells in receiver. But receiver can be plugged into AC. Only drawback is that the RF signal gets attenuated by proximity to all metal mailboxes allowing for poor range. Also the sender is so big it takes up room from your mail. It’s the perfect quick & dirty project though…

    And if the little box in this hackaday doesn’t get a panic call to the USPS dispatcher for “suspicious package found” this huge thing certainly will. BTW – USPS supervisor comes out to inspect incident before calling local law enforcement or federal DHS.

    1. Oops! I forgot flasher stops flashing when the carrier closes the door. A simple SCR (silicon-controlled rectifier *available at RS*) which latches the circuit on until a normally closed SPST momentary action switch is pushed by you to break the circuit. With the SCR you obviously wouldn’t need the elastics. Because you would close the left open door after you retrieve the mail and press the reset button.

  11. The magnet should be applied to the moveable Part, so the rest can be hide in the Box and you dont get in any trouble to take this for a bomb.
    (Sorry for my bad english, i only learned it in school)

  12. Seems nice. I would probably try to find a more elegant sensor arrangement, though. Ideally, you would not need to poll the sensor every 250ms. You could try using an ambient light sensor, a low-power accelerometer, or even just some sort of comparator circuit that trips on flux. 60uA is quite a lot, especially at 9V. If you can migrate to a platform that uses low voltage, that will help too. AVR is crap for low-power wireless.

  13. Wouldn’t a deadman switch work better so you can run the device to the back of the box and run the antenna out of a small sealed hole from there? Hall sensor just seems to be a bit overkill since this is not a rapid moving part.

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