I'm having trouble believing that RCA's Airnergy, a "WiFi hotspot power harvester" unveiled at CES, can actually charge its internal battery from WiFi radio signals.
The Airnergy has a battery inside it, so you can just carry it around and as long as you're near some WiFi, it charges itself. Unlike a solar charger, it works at night and you can keep it in your pocket. Of course, proximity to the WiFi source and the number of WiFi sources is important, but at the rate it charges, if you have a home wireless network you could probably just leave anywhere in your house overnight and it would be pretty close to full in the morning.
A commenter on OhGizmo! offers the following:
Here's some math. Long story short, by my calculations, 100% efficiency and absorption at 5 feet away from a 100mW home router, (reasonable figures), it would take 34.5 years to charge that blackberry battery.
It's not a Dyson Sphere, so you only get the power that hits the antenna.
Surface of a sphere = 4pir^2, r = 60" (5 feet).
Surface area of a 5' sphere = 45,216 square inches.
The device appears about 2" x 3" = 6 square inches.
The device then picks up, best case, 0.000133 of the power out from the router, which is 100mW, so.. 0.0133mW
If you leave it there for 24 hours, 0.0318 mWh are stored.
According to Will's battery, it has ~4,000 mWh capacity.
So, it would take 12,579 days, or 34.5 years, to charge your blackberry battery once, presuming 100% absorption, no losses.
(BTW, What is that dent in the gadget about? Looks like someone poked it with an awl.)
RCA Airnergy Charger Harvests Electricity From WiFi Signals
Dyson, makers of high-end vacuum cleaners and other gadgets that do clever things with air, is moving into beauty products. The Dyson Supersonic hair dryer promises a premium model’s power in a smaller, quieter package, and was built around the company’s smallest motor yet. It’s priced at $400, too — apparently not unreasonable for salon […]
Doniguitar — makers of the Rebel Bass Millennium Falcon bass guitar — also make the NES Paul, a guitar whose body is made from hollowed out, vintage Nintendo Entertainment Systems.
For years, Geoff Manaugh has entertained and fascinated us with his BLDGBLOG, and now he’s even better at full-length, with A Burglar’s Guide to the City (previously), a multidisciplinary, eclectic, voraciously readable book that views architecture, built environments, and cities themselves through the lens of breaking-and-entering.
You never know when new projects, ideas or opportunities can drop into your lap at a moment’s notice. That may require you to learn a new programming language like Python. Or maybe you need a primer on 3D game development. Or you might realize you could use a serious brush-up on iOS mobile creation.Point is, […]
Isn’t it about time to stretch what your Mac can do? I mean, you’ve got plenty of great programs now…but don’t you think you could use some new tools to get your creative, analytical and organizational juices really flowing? It’s spring, so we cleaned up a whole bunch of super-cool apps lying around and packaged […]
In the world of app development, there’s no greater arena to find success than with Android users. About 80% of the smartphones in use today worldwide operate on the Android operating system, so if you build a great app that Android users love, you’re an international rock star. You’ll be able to make sure your […]