Pixel Envy

Written by Nick Heer.

Archive for September, 2009

Thoughts on Wireless Power

Imagine, if you will, your cell phone. It looks the same, costs the same, and connects to the same cell networks. But you never have to charge it, and it weighs 50% less than it did before. Imagine the same for your laptop, your iPod and your video camera. This would be a boon to anyone who’s owned an electronic device and forgotten to charge it the night before (pretty much everyone). And I have some ideas and questions. First, however, a bit of background information.

In 1820, a French physicist by the name of André-Marie Ampère discovered that electric current produces a magnetic field. He described this in his theory, and as a result of its groundbreaking status in the study of electricity and electromagnetism, the SI unite of current (the ampere) was named after him. Eleven years later, Michael Faraday described his law of induction. Fast forward to 1894, when Nikola Tesla lit a series of lightbulbs wirelessly, as if through magic and wizardry. Since then, the idea of transmitting electricity wirelessly has had one proof of concept after another, but the technology isn’t really available to consumers in a meaningful way.

There are two main types of WiPow (I’m going to abbreviate as such): near field and far field. The first type is already available to consumers in a variety of ways, but since they have to be used in such close proximity with the power source, they’re not exactly massive hits in my mind. A good example would be Palm’s Touchstone dock for the Palm Pre. You set it up on your desk, attach the backplate to your Pre, and you’re ready to charge it wirelessly. Except, it’s not exactly a stellar experience. To charge wirelessly, you have to pull the phone from your pocket/briefcase/coat and attach it to the Touchstone (it’s magnetic). It will then charge. This obviously eliminates the extraordinarily complex procedure of attaching a USB cable. You can’t even keep the Pre in your pocket as you’re sitting at your desk, having it charge while you’re playing Tetris. I see the proof of concept in this, but is it really worth $70 to avoid plugging in a cable?

These near field WiPow systems are also used in RFID applications. In all cases, the near field devices don’t require too much power. These applications are more about unnecessary hyping over insignificant details than the fantasy world I described earlier. Which segues nicely into the next step — far field WiPow, where the action really heats up.

In 1994, a group of scientists wirelessly transmitted 10kW of power over 700m to a tiny, remote island which didn’t have electricity up to that point. The only drawback was that the receiving antenna wasn’t exactly pocket-sized (background). Since the far field type is capable of transmitting greater amounts of power, I have a few ideas.

Imagine that all WiFi base stations, all cell towers and wall outlets transmitted a WiPow signal. Your cell phone would practically never need to be charged, especially if you live in a large city (note that the previous sentence does not apply to AT&T customers). Your iPod touch, whenever it’s connected via WiFi would also be charging. You can imagine the world of possibilities here. But, as I see it, it raises some important points.

When you’re out of range of a cell signal, your phone probably doesn’t have a plug on the side for telephone cable. You don’t carry around an ethernet cable, should your iPod drop its connection. So would either of those devices conceivably need a battery? Truthfully, I don’t think batteries will be completely eliminated, but perhaps they’d only hold an hour charge. How about laptops? Would those need a large battery any more, or could it be shrunk down to a maximum 2 hour charge?

How about the non-WiFi, non-cell devices, such as, say, an iPod nano? Earlier, I mentioned the idea that wall outlets could provide a WiPow signal. Since we’re pretty much always in range of one of those, would they need a battery any more?

If a wireless power company were founded, and set up towers all over the city, would you pay for a monthly plan in order to have power virtually everywhere? Do you think such a company would charge by amount used, as your current power company does, or would they charge by duration of use, as a cell company does?

I’m looking forward to hearing any comments, questions or ideas that you have on this. Sidenote: the styling for the comments area is very broken — I’ll try fixing that this weekend.