Another energy harvesting impractical idea? - Page 1
Forum section: electronics / general

author: mcinque
author_rank: Unknown
timestamp: May 05, 2015, 09:55:20 pm
content: http://techcrunch.com/2015/05/04/nikola-labs-launches-iphone-6-case-which-harvests-electricity-from-the-air/"The offending Disrupt startup is Nikola Labs, and they’re gearing up to launch a Kickstarter for a very special iPhone 6 case. This case uses small, energy-harvesting antennas to gather RF energy from the cellphone tucked away in this case. This energy is then sent to a rectifier where it is converted into something the Apple Lightning connector can sip power from. According to Nikola Labs, this RF harvesting antenna takes energy from the transmissions of the iPhone 6 entombed in this case, converts it to about 5 Volts, and uses that to charge the iPhone battery."Isn't a little bit unpractical and inefficient? I mean: did they do some math to realize how much rf power you need to harvest to charge the phone battery or they hope simply to raise money by kickstarter?And... it's only my impression of this kind of "energy harvesting wonders" ideas are more popular in the last years?

author: corrado33
author_rank: Frequent Contributor
timestamp: May 05, 2015, 10:13:34 pm
content: Hm, let's take the energy needed to let the phone connect to the towers and make it charge the battery. At least that's my take on it.GENIUS.

author: c4757p
author_rank: Super Contributor
timestamp: May 05, 2015, 10:17:35 pm
content: Of course it's impractical.Rule of thumb: if they mention Tesla, it's utter bullshit, don't even bother reading past that name. I can only think of one exception.

author: tom66
author_rank: Super Contributor
timestamp: May 05, 2015, 10:21:21 pm
content: Quote from: corrado33 on May 05, 2015, 10:13:34 pmWell, actually... If this idea DID work, it wouldn't take any more energy away from the towers.Think of it like installing a solar panel... that does increase the load on the sun and it won't make the sun dimmer... although it would block something in its path (so if this device harvested the energy from cell signals, it's reasonable to consider that it would also block them getting to the phone, as it's a case and will surround the device.)Anyway, it won't work, because the received power is well under a milliwatt. My phone has 2/4 indicated signal strength (arbitrary units) right now and shows -98dBm signal strength (under Developer Options menu), which is about 0.1pW. During normal use, I've never seen it go beyond -70dBm.

author: corrado33
author_rank: Frequent Contributor
timestamp: May 05, 2015, 10:51:43 pm
content: Quote from: tom66 on May 05, 2015, 10:21:21 pmThat's what I was getting at.

author: amyk
author_rank: Super Contributor
timestamp: May 06, 2015, 12:53:09 am
content: The phone generates RF from power supplied by its battery, which then gets captured and used to charge itself, with massive losses in the loop...?QuoteBullshit. The phone uses only as much power as it needs to keep in contact with the closest base station, and continuously adjusts this power.This is basically the same idea as those "free energy" schemes with a generator and motor connected together.

author: mcinque
author_rank: Unknown
timestamp: May 06, 2015, 11:09:46 am
content: How can unpractical ideas like this be posted also on hackaday...

author: donotdespisethesnake
author_rank: Super Contributor
timestamp: May 06, 2015, 06:08:18 pm
content: Quote from: mcinque on May 06, 2015, 11:09:46 amSince Hackaday were bought out by a faceless corporate that claims to be "Innovating the Sites that Engineers and Electronics Buyers Rely on Daily", they seem to be more likely to post clickbait. Controversial articles create page views. It's all about "monetization".

author: mcinque
author_rank: Unknown
timestamp: May 06, 2015, 07:57:02 pm
content: Quote from: donotdespisethesnake on May 06, 2015, 06:08:18 pmI understand that, but their credibility is gone...Quote from: c4757p on May 05, 2015, 10:17:35 pmindeed!Quote from: tom66 on May 05, 2015, 10:21:21 pmThis is a crystal clear example.Quote from: amyk on May 06, 2015, 12:53:09 amYeah, exactly the same.But the question is: it's only an impression of mine, or this kind of "energy harvesting wonders/bullshits" ideas are more popular in the last years?

author: smjcuk
author_rank: Frequent Contributor
timestamp: May 06, 2015, 07:58:16 pm
content: Also if you look at hackaday, 90% of it was a new way to flash LEDs with an arduino or some vacuous 'maker' circlejerking over some outright dangerous thing attached to the mains. There was rarely anything credible or interesting. Corporate sell out was inevitable as is magic unicorn poop. In fact its akin to homeopathy - just because the signal is there doesn't mean you can power a Prius off it.I'll keep my neckbeard, bag of BJTs and eventual heat death of the universe thanksEdit: these idiots have been around forever. My physics A level teacher was into it back in the last century. You can tell why he didn't last in industry can't you?

author: Sigmoid
author_rank: Frequent Contributor
timestamp: May 06, 2015, 09:30:06 pm
content: Quote from: tom66 on May 05, 2015, 10:21:21 pmIt wouldn't magically siphon power out of the towers or the phone, but it would impede connection.Quote from: tom66 on May 05, 2015, 10:21:21 pmYea... The sun is most certainly "dimmer" if you are standing in the shadow of a solar panel.This design is about as smart as placing a photoelectric panel in the path of a camera's flash, in order to "harvest energy" to charge the camera.

author: Galenbo
author_rank: Super Contributor
timestamp: May 07, 2015, 10:20:46 am
content: Quote from: mcinque on May 06, 2015, 07:57:02 pmSome characteristics seem constant:-Powerpoint presentation and a guy that could also be a politician or standup comedian.-Overclassy fashionate trendy spectators.-Media/video campaign that costs more than a car.-Absence of specs.-strong push to get it polarised as believers/nonbelievers.