Adding facts together, or why you can't charge your cell phone from wifi

Got this random bit of tech news from Nabil Maynard (@Nadreck) from the twitter stream the other day… The article was about a device that can recharge your cellphone by converting ambient wi-fi radio frequencies into electricity. (RCA's Airenergy charger converts WiFi energy to electricity)

Before getting into the physics of this, I had one of those cynical 'That can't be right' moments. My first thought was that there should be a lot of OTHER ambient radio frequency bouncing around that should be a lot stronger than wi-fi. I mean, why wi-fi? Other than saying 'why, oh why, wi-fi?' is so much fun…

Then the math kicks in (thanks to the comments in the article). The output from a wireless router is around 100 milliwatts, or .01 watts -- it would take about 250 hours to charge a device using that kind of output. Now, the idea is that the device collects and stores a charge in its own battery all the time, so you can get a quick hit, but the reality is you'd still have to wait a week to get that charge back on this device…

My point in posting this here is basic critical thinking. Well, I say basic, but it's not that basic when it's so rarely used. The article in question didn't do the extra math or try to prove or disprove the idea that this device works, it took readers to do the math and disprove it, and very few of those readers at that. Most people just said, coool…

While one school of thought says 'just post the facts' we need people to report more than the facts they were given. Do a little research and add a little more to the world than just forwarding stuff along and maybe the world will be a slightly better place…