停车场找不到车怎么办？试试借你的脑袋一用！

2023-03-01 10:03

对有车一族来说，在停车场找车绝对是一件极具挑战性的事情。停车的时候明明记得停在了什么位置，但找的时候面对茫茫车海，还是会经常忘记。这位外国博主告诉你，借用自己的脑袋当天线，可以快速定位自己的车！

汽车遥控钥匙方便携带和使用，但超过一定范围灵敏度会降低。你万万不会想到，此时你的脑袋大有用处。把车钥匙抵住下巴后再按下按钮，就能够在更远的距离内解锁自己的车辆。解锁提示音一响，找到车不就轻而易举了吗？

Keyless entry remotes are great, but they don't always work how you want them to. One of the most common complaints is that they just don't reach far enough. Surprisingly, the key to fixing this is actually in your head. If you touch the remote to your head while pressing the button, you can unlock your car from a further distance.

这是什么原理呢？博主在视频中解释说，汽车遥控钥匙通过发送短距离无线电来工作，这种信号通常能传播5到20米，再远就传不到了。而头部可以起到放大信号、增加传播距离的作用。

Car remotes work by sending out a short-range radio signal. That signal usually travels about 5 to 20 meters until it peters out and can't reach your car anymore. But you can use your head to amplify it, increasing the distance it can travel.

和身体的其他部分一样，我们的头部含有大量水分。当你把车钥匙贴在脑袋上，遥控器发出的电磁波（electromagnetic wave）会与脑袋里的水分子（water molecule）发生相互作用，让它们动起来。水分子的运动产生的波和遥控器发出的波叠加，就扩大了信号传递的范围。

Just like the rest of your body, your head contains a lot of water. When you hold the key fob against your head, the electromagnetic waves from your car remote interact with the water molecules in your head. This moves them around. This movement creates a wave that adds together with the remote wave, amplifying it and increasing its range.

在2010年，由BBC出品的节目《疯狂汽车秀》（Top Gear）就曾做过类似的实验。节目主持人杰里米·克拉克森（Jeremy Clarkson）在空旷的场地做起了测试。

《疯狂汽车秀》节目中，主持人在距车30米处成功解锁。图源：YouTube@Top Gear

他先是走到距离车约30米的地方，用通常的方法成功将车子解锁。之后，他继续后退，退到距车子超过50米的位置，再按下按钮，发现信号已经无法传递到车内了。接下来，杰里米·克拉克森站在原地，把钥匙对着太阳穴。神奇的是，同样的距离下，车子解锁了！

At first, Jenemy Clarkson was 40 yards from the back of his car and the central locking was still working fine. He then went back another 10 to 15 yards and he was out of range. but when he put the key against his head, it was working.

这个实验结果让杰里米大为吃惊，当即在节目里兴致勃勃地研究起解锁姿势，呼吁知道原理的观众积极投稿，解释这一现象。

Top Gear节目中，主持人将钥匙抵在太阳穴进行实验。图源：YouTube@Top Gear

硅谷无线电工程师蒂姆·波扎尔（Tim Pozar）解释说，大脑是一个很好的电容因为它含水量很高，通过“电容耦合”（capacitive coupling），即一种借助电容传输能量和信号的方式，可以让车钥匙的信号范围增大好几个车位。

The trick turns your head into an antenna, says Tim Pozar, a Silicon Valley radio engineer. Pozar explains, "You are capacitively coupling the fob to your head. With all the fluids in your head it ends up being a nice conductor."

用头做汽车钥匙信号放大器甚至出现在了2016年在美国上映的电影《爱乐之城》（La La Land）里。原来这不是一个编剧空想的方法，而是有一定科学依据的。不过，关于片中提到的“辐射”副作用的问题，现在还没有官方的科学解释。