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
At Reddit, mtietje posted this remarkable photo of their lockdown project: an iPad stand made using an old Macintosh SE/30. The display size is perfect for the 9.7″ iPad, and now that iPadOS can use mice they work much better as “normal” computers. Se/30 shells turn up on eBay now and again. One’s there now […]
A $350 USB device claiming to block 5G radio signals is just a cheap unbranded thumbdrive, report security researchers. The makers of the “5GBioShield” claim their USB stick can block electrical waves through a “proprietary holographic nano-layer catalyst” technology. It purportedly does this by “balancing” all the existing radiations around you to create a protective […]
COOPH put together a video featuring DIY smartphone video rigs put together with stuff lying around the house. Want to make your smartphone footage more creative than ever? In our latest video the COOPH photographers share some of their best hacks on how to create stunning images and videos with your smartphone and everyday tools, […]
With everything happening in the last few months, we all but guarantee no one has been thinking about their taxes. That’s understandable — because, beyond all of our current concerns, nobody enjoys the whole tax filing process during even the best of times. Unfortunately, Benjamin Franklin was right — taxes truly are as inescapable as […]
Most parents know that giving their kids educational toys and other projects will expand their minds. But what many might not realize is that physical play is actually building their mental abilities as well. Studies are still in beginning stages, but some early research supports the theory that kids who get the chance to get […]
Not every house has a fireplace. And to be honest, not every homeowner wants to deal with the hassles and maintenance of a fireplace. But it’s tough to argue that the intoxicating glow and dance of a licking flame isn’t mesmerizing, not to mention all of a fire’s practical uses. For those looking to enjoy […]