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
Benji Edwards’s guide to preserving vintage electronics is a fascinating look into all the ways that even solid-state gear can go off in long-term storage: a lot of stuff (batteries, capacitors and even rubber) can leak viscous, electronics-destroying liquids; plastics break down in UV light; mold and corrosion eat your gear from within; spiders, crickets […]
Indiana U is selling off a huge lot of lab equipment, including these space-pod-looking gantries. Winning bidder is responsible for dismantling and shipping. “To give someone an idea of how large these are, there are two pits that they sit in. Each of the pits are 28’x35’x10′ deep.”
Vertu, the “luxury” cellphone maker whose handsets look like drug cartel handguns and are always comically obsolete, went out of business last month, reports the BBC. It is to auction off its inventory. Bids start at $26,000. Thuy Ong: The auctioneer, G J Wisdom & Co, says the phones are a mix of concept models […]
The Pry.Me Bottle Opener holds tens of thousands of times its own weight, and you can pick one up now from the Boing Boing Store.This remarkable keychain is considerably smaller than any of your keys, but don’t let that fool you: it can easily open any bottle, and could even tow a trailer full of […]
Guaranteeing your privacy online goes way beyond checking the “Do Not Track” option in your browser’s settings. To ensure that your internet activity is totally hidden from Internet Service Providers, advertisers, and other prying eyes, take a look at Windscribe’s VPN protection. It usually costs $7.50 per month, but you can get a 3-year subscription […]
This project management bundle will help you get organized and learn how to lead a team to success. You can pay what you want for these five courses when you pick them up from the Boing Boing Store.To help you become an invaluable asset for your company, this bundle includes a curated collection of professional […]