Just heard about "Freevolt" - another scam / marketing bs or real useful tech? - Page 1
Forum section: electronics / general

author: docpaul
author_rank: Newbie
timestamp: October 01, 2015, 10:11:29 am
content: Drayson Technologies today announced Freevolt, a system that harvests energy from radio frequency (RF) signals bouncing around in the ether and turns it into usable, "perpetual power."http://www.getfreevolt.com/

author: crispy_tofu
author_rank: Super Contributor
timestamp: October 01, 2015, 01:37:47 pm
content: *sigh*

author: rolycat
author_rank: Super Contributor
timestamp: October 01, 2015, 02:14:46 pm
content: On first inspection it looks fairly legitimate, if you allow for the usual BS spouted by the marketroids to get media attention.The company is owned by Lord Drayson, former Minister for Science. He also has a PhD in robotics, so should be a little more technology-savvy than the average CEO. Supposedly it's based on research done at Imperial College, London.It appears that the technology is primarily aimed at ultra low power sensors of various types, including a wearable pollution sensor. They can harvest energy from Wi-Fi, mobile networks and digital TV transmissions.

author: daqq
author_rank: Super Contributor
timestamp: October 01, 2015, 02:20:21 pm
content: Since the target market is something that might run off of the few micro watts it can gather, I'm guessing that it MIGHT work, provided that it's in a city or heavily RF polluted area.Added: However, there's more marketing on that page than I like. A photo of the devkit? Some actual technical data (plot of ambient RF power vs output power?)? Instead there's some heavy marketing, buzzwords and that's about it.

author: Mr.Smith
author_rank: Newbie
timestamp: October 03, 2015, 04:28:02 am
content: There is technical data on their website, under Downloads there is a white paper.However, their own white paper comes up with numbers which are internally inconsistent.They mention a typical "connected device" with a CR2032 battery with a lifetime of 6 months, and calculate its power consumption at an average of 165uW. That's about right, and it corresponds to 14.25J/day.Later, they say:QuoteThat also seems realistic. So for a realistic product in a realistic use case, Freevolt can provide less than 0.3% of the product's energy requirements.They also say thisQuoteAnd on this basis calculate that Freevolt can provide 4000 additional readings per day. But this is entirely misleading. It is true that e.g. the Silicon Labs Si7021 only requires about 2uJ to take the lowest-resolution reading, but the energy required to read the value over I2C dwarfs that figure, as does the energy required to transmit those readings using a radio link.There are numerous papers about, and even commercial development kits for ambient RF energy harvesting. The technology certainly is real, and it has its place, but I have my doubts about the claim that the CleanSpace tag will never need recharging.

author: expertmax
author_rank: Regular Contributor
timestamp: October 04, 2015, 04:03:02 am
content: Weirdly enough, media seem to have picked up the news and they misrepresent the product's intended use by writing "You will never have to charge your phone again with this incredible technology"... Ugh marketing, I hate marketing.

author: SteveLy
author_rank: Regular Contributor
timestamp: October 18, 2015, 06:10:58 am
content: There may be another thread on this already.Dave did some excellent videos on the topic of RF harvesting; one that showed he has the wits of a practical physicist. There is nothing new here and no use for this crap. The "Applications" page just reeks of BS but they are careful with the wording of the BS so technically you can't say they are lying. Devices that run on such low powers will run off small battery cells for years, and on solar cells (even if used indoors) for a lifetime.It's marketing BS, that while may be argued to be factually correct, is designed to mislead. A pocket sized solar cell exposed to sunlight for a few seconds will generate more energy than these RF harvesters could collect in a day. Or when you raise your arm, in that single motion you can easily generate a similar amount of energy. Self-winding wrist watches, anyone? They were kinda gimmicky but at least they worked.

author: Ian.M
author_rank: Super Contributor
timestamp: October 18, 2015, 06:48:01 am
content: A fairly small solar cell under ambient room lighting will give more power than a similar size RF harvester.Seehttp://www.eevblog.com/2009/12/04/eevblog-48-solar-power-hope/

author: Psi
author_rank: Super Contributor
timestamp: October 18, 2015, 07:10:02 am
content: Quote from: Ian.M on October 18, 2015, 06:48:01 am+1 to this.That said, if it cost like 20c extra on the BOM to add this to your 12uW IoT device it would totally be worth it and would make a huge difference to the lifespan of its CR2032.Of course it doesn't cost 20c, it costs ~$3-5.

author: rolycat
author_rank: Super Contributor
timestamp: October 18, 2015, 11:52:44 am
content: Quote from: SteveLy on October 18, 2015, 06:10:58 amI don't know that I'd call them gimmicky. They have been around for nearly a hundred years, and most high-quality mechanical wristwatches have self-winding movements. I have worn the same watch for over thirty years, and it still works flawlessly.As for automatic quartz watches such as the Kinetic, Seiko have sold over eight million of them and they are still popular.