For folks wanting to protect their cars from thieves going after catalytic converters, registration tags, etc: I bought one of these Hosmart driveway motion detectors with alarm, and I am surprised at how well this thing works! I use it when parking somewhere and going on a hike with my dog. I have an RV and would hate to come back to find the RV stolen or broken into. I just mount the motion detector in the inside of the RV and carry the alarm with me -- it works at least 1/4 mile away by my testing and probably more. It does not give many (really, any) false alarms -- just alarms when it senses motion from a human or other warm body.
https://www.amazon.com/Hosmart-Rechargable-Driveway-Wireless-Weatherproof/dp/B07PRGGRGW/ref=sr_1_3?crid=4IUS76GA0D06&keywords=hosmart&qid=1669140591&sprefix=hosmart%2Caps%2C817&sr=8-3
1/2 Mile Hosmart Driveway Alarm Wireless Sensor System & Driveway Sensor (I agree that the name of the thing is not the greatest!)
I imagine that if you park your car on the street in front of your house, you would put the motion sensor under the car, hidden by a tire, and it would alert you if someone (or maybe a cat) crawls under the car. Of course, a friend of mine said that maybe you would not want to do anything if the alarm goes off when I was on a hike, since the thieves might have weapons. I'd rather know than not know.
The alarm unit can be powered by 4 AA batteries, or an AC adapter. The motion sensor is charged using a USB cable and any phone charger, and the battery in it still had a charge, enough so the alarm worked fine after sitting six months in storage
I went on a hike last month at a remote area in Puget Sound, and I had a second phone with a working cell data plan (just $10 per month from tello). I put this phone in my car and made sure that it was turned on, that it could get a cell signal where or near I was hiking. I used Google's Find Device app to make sure that my phone was indeed being located and hid it in the car. If the car had gotten stolen, I'd know where the car was. I guess Apple Airtags can do the same thing without a cell phone plan.
