Does anyone have insight on motion sensors that could be used for motion/pressure detection on the perimeter of a home?
Wireless or wired it doesn’t matter, but I can’t seem to find anything that can be buried in-ground - everything is mounted as a motion sensor. Any insights or ideas would be great, thanks!
Sure, these exist as pressure mats. Many are waterproof, for example they are often used as a “doorbells“ on houseboats, but also to indicate when someone is approaching an open bay in a commercial building.
But you almost always have to put the part of the system which is actually going to transmit the signal above ground or the signal won’t get through. So I don’t know if that’s going to help you or not. You can run a cable from the pressure mat itself to the transmitter device, but as a practical matter these are usually limited to about 2 m.
In Addition, these generally have to be buried very close to the surface or the change in pressure isn’t sufficient to set them off. So that’s another factor to take into account.
See the following thread (The topic title is a clickable link)
(I should say also that you can’t do it with motion sensors of the sort that are typically used for a low cost home automation sensor. Those are almost all PIR sensors, passive infrared, and the infrared will not travel through the dirt. but the pressure sensors can work with the caveat noted above.)
I should also say that there are some accelerometers used as buried cables to attempt to detect footsteps, but the inexpensive one almost all have a really high degree of false alarms from passing traffic, high winds, even thunder. I haven’t heard of anyone trying to use them with smartthings, but I just don’t think they’re going to be successful. The pressure mats are a much more targeted approach because they aren’t affected by simple vibration.
There’s an Israeli company named Sensoguard Which makes an accelerometer cable with a higher degree of reliability, but the system costs thousands of dollars, even tens of thousands of dollars, so I don’t think most individual homeowners would be interested.
The facility i work at has a sensor cable that runs thru the fencing around the whole perimeter of the plant…
Buried underground, or just along the fence?
along the bottom of fence. so if you touch the fence or attempt to dig under they will know…
Interesting concept for sure. Do you happen to know what cable it is or the brand?
Ideally even if it wasnt a Smart system I’d want to find something I can have a main terminal to alert me of motion on the exterior of the home. Sounds like I’d likely be stuck with PIR sensors then that are outdoor-proof
These days most people who want that kind of security also have cameras and they just use the motion alerts from the cameras. These tend to be more reliable than the PIR sensors. The price on cameras has come down significantly in the last few years as well, and there are a number of options.
Integration with SmartThings is trickier, but there are multiple choices there as well. Arlo and Ring have official integrations for some (not all) models. Blink and Wyze are less expensive devices, and you may be able to get some integration through Alexa routines. Other brands may require IFTTT or other methods.
This thread has some examples of how people use the motion alert from Ring cameras with smartthings.
2020 Rundown: Ring Products and new V3 App?
Anyway, just another possibility if that might work for you. 
Seen one of these with a 8 meters of pressure hose you bury for driveway sensors https://www.amazon.com/Dakota-Alert-DCRH-4000-Wireless-Driveway/dp/B07PDZPGJ5?ref_=ast_sto_dp
I’ve seen others too, so checkout driveway sensors in your searches.
The military uses sensors like the OP describes. I suspect they are very expensive and may not be for sale to non-military/law enforcement.
In the US, you can get them, but, yes, very expensive. Tens of thousands of dollars expensive.
Dakota driveway alert systems come in two types, but neither really fits the use case in this thread.
The ones with a cable that you bury won’t detect people.
The Duty Cycle Probe Alert DCPA-4000 is a driveway alarm system that uses a magnetic probe that senses the change in magnetic field caused by large moving metal objects.
The ones like the one linked to at Amazon with the long rubber hose cannot be buried. You just lay them on top of the driveway so cars will drive over them. So they are really easy for an intruder not in a car to avoid, and for that matter, pretty easy to move out of the way. Beyond that, most of them are calibrated for a weight of more than 1000 pounds, for example, they won’t detect a bicycle.
Most other brands of Home driveway detection systems are similar. if they use pressure sensors, they are set for very heavy loads intentionally not to go off for people or animals.
If they use buried cables, again, they are looking for cars and are probably set for metallic detection of very large metal objects.
They’ll work for some use cases, particularly if you are trying to detect vehicles, but not if you just want to detect people trying to sneak into the yard.