This might be a wonderful Segway into the entire subject of energy. Just as the car's sensor responds to the electromagnetic signal radiated from the key at a specific designated frequency, so too does your eye's retina respond to the frequencies of electromagnetic energy radiated by the sun as light waves. And what we call "light waves" are actually just that spectrum of electromagnetic frequencies to which the retinas in our eyes react. There are radiant energies that go completely and harmlessly through your body all day long, and some that go invisibly through your body but cause damage to cells along the way.
If you're innately interested in physics, there're a whole lot of directions your research can take you. I urge you to not limit your research to car locking systems.
Sincere best with this. Physics is a truly wonderful and fun subject.