科学美国人60秒 这部手机不需要电池（在线收听）

A dying battery is a huge annoyance for cell phone users. But for engineers? It's inspiration. "Can we design a smartphone which can make a phone call and have a conversation without the need for any kind of battery?"

电池没电对于手机用户来说是一大烦恼，但对于工程师来说，它就是灵感。“我们能设计一部可以在不需要任何电池的情况下就能打电话交谈的智能手机吗?”

Shyam Gollakota is a computer scientist at the University of Washington. And he and his team have indeed designed a battery-free phone. It looks like a circuit board, with touch-responsive numeric buttons. And it runs on just a few microwatts of power, which it harvests from light, and the radio signals emanating from a nearby wireless base station.

夏玛是华盛顿大学的一位计算机科学家。他和他的团队真的设计出了一个免用电池的电话。它看起来像一个电路板，带有触摸响应程序的数字按钮。它仅靠从光线中获取的几微瓦的能量运行，并接收附近无线基站发出的无线电信号。

The team achieved the battery-free, energy-efficient design by ditching two power-hungry features of modern cell phones. The test unit skips digital to analog conversion. And does not generate its own wireless signals to make calls.

通过甩开现代手机的两个耗电特性，该团队实现了无电池节能设计：试验设备使用了数模转换技术，而且它无法通过产生自己的无线信号来打电话。

Instead, in receiving mode, it absorbs incoming radio waves from the base station, and converts them directly into vibrations of its speaker. In sending mode, it uses the vibrations of its onboard microphone to change the way radio waves are reflected back to the base station.

相反，在接收模式中，它通过接收来自基站传入的无线电波，并将它们直接转换为扬声器振动。在发送模式中，它利用内置麦克风的振动来改变无线电波反射回基站的方式。

And it worked, to make a Skype call: <"Hello?" "Hello, from the battery-free cell phone.">

而且它成功了。我们来打了一个网络电话：<“你好?”“你好，这是来自免用电池手机的电话。”>

The findings appear in the Proceedings of the Association for Computing Machinery on Interactive, Mobile, Wearable and Ubiquitous Technologies.

这一研究结果发表在计算机协会关于人机互动、移动、可穿戴和普适技术的会议上。

The demo device does have limitations: It can only stray 50 feet from the base station. The voice quality is pretty lo-fi. And you can't check Facebook either—yet. "Oh, —we're going to get there. This is again a first step. Think of it as like: you need to make a first move to get someplace where you can harvest power to do other operations."

演示设备的确存在局限性：它必须在距离基站50英尺的范围内，且音质很低。另外它也不能用来浏览社交网络脸书。“但是，我们正在努力实现这个功能。这只是个开端。大家可以这样想：你需要迈出第一步，才能到达某个地方，以收获力量来进行其他操作。”

And it’s those other operations that will ultimately be crucial. Because, battery or not, you could argue that voice calls are by now just a neat retro feature of our ever-smarter phones.

而那些其他操作最终才是至关重要的。因为，无论有无电池，你都可以说目前这种语音通话只是我们即将变得更智能的手机的一个简单的复古特征。