Using ST Multisensor accelerometer as mailbox mail detector

For anyone interested in detecting mail delivery to their mailbox,

I use a Samsung/SmartThings (ST) Multipurpose Sensor (MPS). While these are generally promoted for their Open/Close (door/window) sensors, they also have a very good accelerometer in them. As a mail detector, in my hands, the MPS accelerometer does pretty good, but not 100%. Very roughly 90% of the time.

Actually sensing Open/Close, per se, with a metal mailbox is a very awkward proposition both because it’s a metal enclosure, and just the pure geometry of trying to mount the sensor around the arched opening and/or where it’s not blocking/knocked off by mailman or seen and taken by kids walking down the street. Maybe you could put it up underneath (the bottom edge of our plain metal mailbox door swings back when you open it) but then the unit would have to be mounted right up against a nice big metal thing when reception isn’t good already (see below). And even then it’s still awkward geometry; you don’t have a ton of space, and are trying to detect something moving just a small distance, in a radial fashion (axis around the mailbox door hinge).

As an aside, I might mention that, for the umpteenth time I wish someone would make sensors that are separate from the rest of their unit. Here, it would be wonderful if there was a teeny-tiny open/close sensor (or accelerometer) that was on a very thin wire 2’ long or whatever (but easily extendable becuase it’s, well, a plugin sensor, thank you very much). Meanwhile the actual device including antenna could be put some other better access / broadcasting place. Sometimes it really is a huge inconvenience that companies always insist on putting all parts into one inseparable package. There are also good reasons for everything to be in one package, of course. I just wish that not every single company, every single time, insisted on it.

So anyway, instead of trying to use the MPS’s Open/Close, I simply stuck it to my wooden mailbox pole, up in the little V alcove of a little buttress beam supporting the mailbox. It’s hidden from view and rain here (so far, fingers crossed). I used 3M VHB #4920 double-sided tape for a solid yet non-permanent bond (to catch the movement). I also have it oriented right-side up, which is to say, I stuck the white top of the MPS to the underside of the mailbox beam. This way, any moisture that might by chance get there will tend to roll down the sides and maybe only tend to moisten the join there. And it would never pool inside the white cap (which it would do if I stuck the gray bottom of it to the underside of the mailbox beam).

These ST multipurpose sensors accelerometers are incredibly sensitive (just a little tap is enough) and always signal, when tested inside my home. In fact I had to send one back because it was super over sensitive… not only would it go off with people walking down the hall when it was attached to a wall near there, but it even started to go off spuriously. Maybe it was just detecting Hawking radiation particle annihilation.

So the ST Multisensor was great for sensitivity and sending a signal. But its Zigbee signal was problematic, apparently. It is about 50’ open air from mailbox to front of house, then another 40’ or so to my ST hub. If I plugged a Samsung SmartThings Outlet into a wall receptacle on the front wall of our house (inside the house) as a relay, reception was extremely spotty. This is behind the brick wall front of our house. But if I rest it on the window (wood frame) on the inside of the house with old-school metal screen on the window, it does much better (85%). Maybe it would be 100% if I took down the screen or actually put the Outlet outside (but then it’d be exposed to elements). It has done fine with occasional Atlanta GA rain and humidity for several months, so mounting it under the beam seems to be okay. Definitely not covered by warranty though, I bet. :innocent:

If my MPS doesn’t detect a mail delivery, at this point I can’t be sure if it’s because of reception, or because the mailbox simply wasn’t shaken much. If I put mail into it very lightly, it will not go off. If I deliberately bop the mailbox a few seconds later, it will almost always go off. So, in ideal testing conditions, the actual amount of acceleration of the mailbox does matter. (Remember it’s mounted on 2-sided tape which probably damps it a little. You could screw it on but that’s more work and not completely easily reversible.) The good news is that mailmen are not in the habit of lightly and gently taking their time to close the mailbox door. Most of the time it seems to work, but not always.

For the record, I also tried a Z-Wave Aeon gen5 Multisensor 6. Its Z-wave can go much farther (of course), but its accelerometer is clearly not as sensitive as the MPS’s. It was simply not good enough.

I also posted accelerometer data captured by @krlaframboise’s Simple Event Logger over in this thread, if anyone wants to see what it looks like.

I also once asked if the orientation of the MPS matters (to optimize detection) but the answer seems to be No, it’s equally sensitive in all directions. That thread also has some clues as to the chip used, and accelerometer sensitivity. (Thanks @tgauchat!)

For the record, the ST Multipurpose Sensors have a setting “Do you want to use this as a garage door opener”. This is irrelevant to using it in my particular accelerometer setup; it doesn’t matter. Maybe the garage door has it sense a change in angle, I don’t know. (If it does, that could be used in interesting ways.)

I hope this setup helps someone. Detecting mail was one of the two main reasons I decided to “go smart home” in the first place, but in reality (if you read through the lines) it was highly problematic. In fact, it was a complete fail initially (you can’t really use Open/Close, and the accelerometer is a rather hidden property). And the distance was a real problem, next to the metal mailbox.

So perhaps this will give someone else hope.

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tl;dr but I got the main points. This is an easy way to get notified when mail comes. I did the same thing with a 1st gen SmartSense Multi 3m’d to the back of my aluminum mailbox. All I did to “waterproof” it was to smear some silicone caulk all around where the plastic case parts join and where the tabs came together.

It’s been through snow and rain, and so far it’s worked perfectly. Distance is about as far as yours, with an Iris smartplug in the garage acting as a zigbee repeater. I have yet to miss a mail notification. I also created my own DTH to remove the open/close tile and to use motion/acceleration as the main tile. I’m using a custom SHM rule to notify me when there’s activity at the mailbox.

Ah, good thinking on the caulk. I guess it’s slightly messy if you need to open it, but that’s easily dealt with. I guess you could even use wax… it’s better than nothing.

I actually use it mainly as a temperature sensor as far as how it’s set up in the SmartThings app for me (along with 12 other temp sensors), and the mail delivery only appears as a notification I set up through a custom SHM rule. That’s all I want - a ding when I get mail. Plus to keep all my ding notifications straight I paired this one with a TTS with Tasker. I used a fem Italian voice so when she says “MB” it sounds like “emma bee”, laugh.

Hey John,

I am trying to gather some stats,

Do you have long-term records and can you say -

What kind of temperatures has it been through? And it’s still living?

Do you have any long term log like the CSchwer Log on it?

The question is, can it push past its ratings. Which amounts to, don’t even look at the ratings … what has it endured in your hands?

Plus how long has the battery lasted so far?

If you don’t have long-term data from the device per se, but can look at long-term weather records for your area and can say it didn’t stop when things were extreme (as far as you know), that’s good, too. Either way, mind saying your general area?

Thanks for your help if this info is easy for you. If not, don’t worry about it.

We live in NC, and have seen temps go into the teens and over 100 since mine has been in place. No problems with major temp swings. Prior to being on my mailbox it was in one of my freezers where it was always always below zero. It gets pounded by rain and my sprinklers, and no problems there either, but I did run a bean of exterior silicone sealant where the 2 halves come together.

I don’t use that app, but instead I use Simple Event Logger for many of my devices. Unfortunately I don’t capture any data for that sensor since I’m just concerned about mail notifications. I also get notified of severe thunderstorms because every once and a while the thunder does get a bit loud…

I know I have, but I guess it depends on where you live. I personally don’t think you’ll have a problem. Keeping out of direct sunlight will help prevent crazy temps.

I put new batteries in on January 28th, and I’m at 88%. If you’re familiar with how these devices report in ranges, that’s pretty good. This is a gen 1 version on the sensor I got way back when ST just came off kickstarter. This is only the second set of batteries I’ve had to use. Like I said above, it’s been in my freezer and also as an open/close sensor on a porch door.

No problem providing you info. I’m glad to help in any way.

Thanks greatly John, it sounds like yours is doing as well as mine. I am working my way to some wiki articles on this and other sensors. I’m trying not to announce my site until I can get it in better shape, it could well be months, but I’ll share a link soon as I can. It’s good to have some other corroboration that this little sensor can handle being outdoors fairly well, as long as you keep it dray and out of the sun.

John, I would like to learn more about what you did to add a sensor to your mailbox. I need to do something simular… something that would alert me when the door was opened. Can you help me out?

Depending on how far your mailbox is to one of your repeaters, you could just use a simple open/close sensor. I am in NC and mines have been going strong for over a year without any issues.

I used a then $10 Visonic Contact. It has a low profile and works flawlessly even through the winter.


This can be a very useful project, and a number of community members have approached it in different ways. If you’d like to see some of the posted project reports, check the quick browse lists in the community – created wiki, look in the project reports section, and there’s a list there specifically for project reports on mailbox notifications. :sunglasses:

Edit: that setting probably controls whether that sensor is a tilt sensor or contact sensor

As far as the setting on the smartthings multi-sensor, “do you want to use this on a garage door”, I do not remember exactly what this does, but I am pretty sure it would NOT have anything to do with vibration sensing, it may or may not change the orientation for tilt sensing, or maybe the multi does not report open and close tilt events unless this is set. Tilt sensing in my experience has been VERY reliable for all devices that I have tried tilt sensing on. This setting does change the graphic that is shown in the smartthings iphone UI. This I just tried

You are complaining about the reliability of vibration sensing, and I agree with that, I have had mixed results with vibration sensing.

Tilt sensing works

While I agree that the zigbee signal probably will not propogate from inside the metal mailbox, have you verified that a zwave plus signal does not work?

I have found that zwave seems to penetrate solid walls much better.

Did you try the Aeon multi-sensor inside the metal mailbox? And are you aware that you can get an open/close event based on the tilt of the sensor?

My mailbox, which is plastic, not metal, I get the open event and then the close event, every time the mail box is opened, and then closed.

I have found that zwave signals are less affected by walls and metal than zigbee.

In my garage I have found that battery powered zwave devices work but zigbee based devices are problematic.

For a garage door and a mailbox I can recommend this device:

And at a cost of $25, it is much cheaper than $60 for an aeon multi-sensor.

In general I really like the smartthings multi-sensors, but only INSIDE my house and NOT in my garage due to zigbee propagation issues.

Hi @adkins147, apologies for the delayed reply. I’ve been traveling the last several days.

If you can find a 1st gen multipurpose sensor, then your setup can be just like mine. The 1st gen detects vibration, unlike the newer ones. With vibration detection, I just have the sensor mounted on the back of the box not visible from the street. If I were to use the open/close feature, I’d have to mount it inside because my wife didn’t like to see the device outside the mailbox. When I tried that I had range issues because my box is a heavy gauge metal box. I had no range issues mounting it outside, so I went with vibration detection.

Depending upon where your mailbox is located from the hub or any repeating device, you may be able to use any generation ST sensor, an Iris open/close sensor, or even zwave sensors. @rontalley is spot on, and his is a good setup too.

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