i was walking in someones garage checking out their truck and i was not even touching it when it started making some high pitch beeping then an automated voice told me to stand back. how did the car even detect me?
It could be or a motion sensor or the static electricity. Those car alarms are rather weird devices.
Many new car alarms can be set off by loud sound, vibration, and motion detection. If you circle it, walk too hard next to it, or make crazy noises it'll go off. Also, you may have touched it without knowing. I set off my car alarm once by barely touching the tire, some are sensitive.
It's done by capacitance. You charge the metal car with a weak charge that people won't even feel. The charge stays in the car because it can't get to ground thru the rubber tires. When someone walks near the car, this capacitance bleeds off thru the person to ground, the security system feels that charge reduction triggers the alarm.
