Professor Roger Bowley unlocks his car from various distances, using waves from his key, brain and a big bottle of water.
The principle is easy as it gets and it stand as the basis of the way microwave ovens work: water acts like an antennae and is also able to heat up. Since our brain contains water and this water has two partial poles, positive the Hydrogen, and negative, the Oxygen, it will interact with the microwave/radio wave from the car remote and amplify that signal.
Professor Roger Bowley uses also a bucket of water to increase the range of the signal. So, if the car remote does nto work as expected, then put it against your head.