Outdoor motion sensors that connect directly to smartthings tend to be unreliable (lots of false alerts) because they’re almost all PIR based, which just measures very small changes in heat moving across the sensor field. So the problem is just a gust of warm air or the sun going behind a cloud can trigger the sensors. In fact, the aeotec multisensor, which is rated for outdoor use, suggest turning off the motion sensor feature altogether if the device is used outside, and just using it for temperature, light, and humidity detection. This problem is even worse for mesh devices, such as those using zwave.
There are some options. See the outdoor motion sensor FAQ, which details them. (This is a clickable link)
That thread is quite long and covers a lot of different use cases, including driveway detection, so for your particular use case I think the short answer is either going to be use three different sensors and set up a zone using Mike Maxwell’s smart app so that all three sensors have to detect motion before you consider it a real alert.
Or, use the Kumo outdoor sensors, but those are going to require also getting their $40 ethernet bridge (one bridge can support up to 40 sensors.) The Kumo are nicely weatherproofed, have better range and fewer false alerts, but it’s a cloud to cloud integration with SmartThings. Or you can use IFTTT. There are quite a few community members using them, but it may not be what you want.
I used a battery-powered electric fence charger for many years. There are some that use D-cells but most are 12V SLA. Solar chargers might work ok with less maintenance.
The fence itself, is very easy to install.
Also there is an integral motion-detecting sprinkler called “scarecrow”, that makes a great racket and usually squirts the owner too. Driven by 9v battery and less reliable. The deer might learn to like it.
I have tried Aoen multi for outdoor motion. Alot of variables. Seems to work okay inside.I was also using it for driveway sensor.
I did find the Arlo motion sensor on the camera to be fairly reliable. Especially if mount it so direction of movement goes across and not toward. But I used it to close my garage door as the car backs out of garage and it was above garage (movement toward and away) worked good.
But I was going to do what your doing for stray dogs in the lawn not just to scare away but also deluit the urine.
Dont use it anymore, found a better way for garage door.