Slashdot Mirror
$500k "Energy-Harvesting" Kickstarter Scam Unfolding Right Now
New submitter FryingLizard (512858) writes For a while I've been following the saga of the Kickstarter "iFind" Bluetooth 4.0 tracking tag. Nothing new about such tags (there are many crowdfunded examples; some have delivered, some have disappointed), but this one claims it doesn't require any batteries — it harvests its energy from electromagnetic emissions (wifi, cell towers, TV signals, etc). The creators have posted no evidence other than some slick Photoshop work, an obviously faked video, some easily disproven data, and classic bad science. So far they've picked up half a million in pledges. With six days to go until they walk off with the money, skeptics abound (10min in) including some excellent dissections of their claims. The creators have yet to post even a single photo of the magical device, instead posting empty platitudes and claims that such secrecy is necessary to protect their IP.
Using just their published figures, their claims are readily refuted, yet still backers flock in. Kickstarter appear uninterested in what can only be described as a slow-motion bank robbery, despite their basic requirement to demonstrate a prototype. It seems self-evident that such scams should not be allowed to propagate on Kickstarter, for the good of other genuine projects and the community at large. Skeptics are maintaining a Google Doc with many of the highlights of the action. Bring your own popcorn and enjoy the show."
Using just their published figures, their claims are readily refuted, yet still backers flock in. Kickstarter appear uninterested in what can only be described as a slow-motion bank robbery, despite their basic requirement to demonstrate a prototype. It seems self-evident that such scams should not be allowed to propagate on Kickstarter, for the good of other genuine projects and the community at large. Skeptics are maintaining a Google Doc with many of the highlights of the action. Bring your own popcorn and enjoy the show."
Surely, though, they must have registered the "iFind" trademark? And if you search on TESS we find:
Owner (APPLICANT) WeTag, Inc. CORPORATION TEXAS 3309 San Mateo Drive Plano TEXAS 75023
With an attorney listed as "Richard G. Eldredge" which corresponds to a local attorney. Before you deploy the door kickers to lynch somebody, that address is just somebody's $200,000 house and could possibly be a random address used by a jerk. Remember that it's entirely possible that this is all a front by some other actor and someone was paid western union/bitcoin to register this trademark through this attorney without realizing they were just being used by literally anyone in the world ... of course, kickstarter should have even better transaction details (hopefully).
My work here is dung.
As somebody familiar with RF engineering, I'd say this is obviously a scam. And it's not a miniaturization issue. It's a power density issue. Yes, I could build something that would gather energy like they're saying. And with the power draw of a BT device, I bet every 10 days or so, I'd have harvested enough energy to run it for an hour.
Fact is, the RF energy needed to be harvested to do even small amounts of work would cook you if you got in the way. The amounts that are just free floating around you from cell phones for example is around -60dBm. Or -90dB. 1dB is 1 watt, -10dB is .1 watt, -20dB is .001 watt, so the typical cell phone signal is .000000001 watt by the time you receive it. And if anybody is going to try to tell me that you're going to power anything off of that sort of energy....yeah, but no. Just no.
It appears, based on my back of an envelope math, it would have enough RF energy to operate continuously at at least 5meters from your typical Wifi AP or router.
5 meters from a maximum 1 W transmitter gives you 3 mW / m^2. The chip you selected runs at least 1.8 V, so it needs ~30 mW when active.... hence you would need an antenna with an area of 10 m^2 to get that type of power to run continuously off a Wifi AP. When idle, you would still need an antenna with ~0.5 m^2, so like 70 cm on a side square. Heck, if your device was an inch square, it would barely be able to power the bluetooth in sleep mode, with no power left over to charge up to allow it to briefly transmit.
And this is ignoring things like the antenna not being able to capture 100% of the power going through it, and that your harvesting chip isn't 100% efficient. The harvester chip gives a minimum RF input of -10 dBm, which means you would still need an antenna 20 cm square to work at that level 5 m from a wifi AP. And this is assuming your AP is working at full 1 W power continuously (In EU they would be limited to 100 mW, for example). If you are trying to power it off the bluetooth of a cell phone, most are class 2 with a maximum power of 2.5 mW, which wouldn't be enough. You have the main cell transmitter which can be up to a watt, but it isn't typically running at full power and has a small duty cycle when not making calls. This also assumes your tag is out in the open, with nothing on top or even behind it that would attenuate the signal, in which case making it brightly colored might be all that is needed...