Ask Hackaday: Global Energy Transmission – Can It Work?

July 7, 2014 by Will Sweatman 177 Comments

Atop a small mountain in Colorado Springs sat the small, makeshift laboratory of Nikola Tesla. He chose this location because the air was thinner, and therefor more conductive. Tesla had come to believe that he could use the Earth as a conductor, and use it to send electrical power without the need for wires. Though some facts are forever lost, it is said that on a clear, moonless night, Tesla flipped the switch that fed millions of volts into a large coil that towered high into the air. He cackled maniacally as an eerie blue corona formed around the crackling instruments, while some 200 florescent bulbs began to glow over 25 miles away.

A magnificent feat took place in the hills of Colorado that night. A feat that surely would change the world in how it harnessed electricity. A feat that if brought to its full potential, could provide wireless power to every point on the globe. A feat that took place almost one hundred and twenty years ago…

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The IFind Kickstarter Campaign Was Just Suspended

June 26, 2014 by Mathieu Stephan 67 Comments

A little more than one month ago we featured a Kickstarter campaign that was raising quite a lot of eyebrows and over half a million dollars. This particular product was a battery-free tag meant to be attached to anything you may lose in your daily life. It was supposed to communicate with Bluetooth Low Energy (BLE) devices and have a 200ft (60m) detection range.

The main claim was that the iFind could harvest enough power from existing RF fields inside a typical home environment to operate for centuries. As Kickstarter just cancelled its funding a few minutes ago it seems that the basic maths Hackaday did a while ago were correct and that the project was in fact a scam. We’ll direct our readers to this particular comment that sums up all the elements pointing to a fraudulent campaign and show you the email that the backers received:

A review of the project uncovered evidence of one or more violations of Kickstarter’s rules, which include:

A related party posing as an independent, supportive party in project comments or elsewhere

Misrepresenting support by pledging to your own project

Misrepresenting or failing to disclose relevant facts about the project or its creator

Providing inaccurate or incomplete user information to Kickstarter or one of our partners

Putting aside this news, this campaign’s cancellation raises a bigger question: why didn’t it happen before and how could we control Kickstarter campaigns? On a side note, it’s still very interesting to notice the nearly religious fervor of the sunk cost fallacy that such campaigns create in their comments.

Thanks [Rick] for the tip!

Ask Hackaday: Program Passes Turing Test, But Is It Intelligent?

June 9, 2014 by Will Sweatman 119 Comments

A team based in Russia has developed a program that has passed the iconic Turing Test. The test was carried out at the Royal Society in London, and was able to convince 33 percent of the judges that it was a 13-year-old Ukrainian boy named Eugene Goostman.

The Turing Test was developed by [Alan Turing] in 1950 as an existence proof for intelligence: if a computer can fool a human operator into thinking it’s human, then by definition the computer must be intelligent. It should be noted that [Turing] did not address what intelligence was, but only tried to identify human like behavior in a machine.

Thirty years later, a philosopher by the name of [John Searle] pointed out that even a machine that could pass the Turing Test would still not be intelligent. He did this through a fascinating thought experiment called “The Chinese Room“.

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Ask Hackaday: Can Battery-Free Bluetooth Item Locating Tags Exist?

May 21, 2014 by Mathieu Stephan 220 Comments

[Vishak] tipped us about the iFind Kickstarter campaign, a 1.25×1.06×0.09″ (32x27x2.4mm) tag meant to be attached to anything you may lose in your daily life. This device communicates with Bluetooth Low Energy (BLE) enabled smartphones, has a 200ft (60m) detection range and a loud alarm. What is interesting to mention is that this device doesn’t need any battery to operate as it

recycles electromagnetic energy and stores it in a unique power bank.

As you can guess, this particular claim intrigued the Hackaday team given that we never featured so small energy harvesting devices. The ‘closest’ thing that comes to our minds is the Allsee project, a simple gesture recognition device that uses existing wireless signals (TV and RFID transmissions) to extract any movement that occur in front of it. However the antenna was quite big and very little power was extracted.

A quick Google search let us know that Bluetooth Low Energy solutions usually consume an idle current of around 10uA @ ~3V. The (very) successful Sticknfind campaign which promoted the same battery-enabled product claimed a one year autonomy with a CR2016 battery and a 100ft range, leading to a ~90mAh/24/30.5/12 = 10.2uA idle current. As we’re not expert on the subject, we would like to ask our readers if they ever came across such energy harvesting performances (3V*10.2uA = 30uW) in a normal home environment. Our very bad maths indicate that if one would like to extract power from a typical Wifi router located 2 meters from you emitting 0.5Watts of power (in a perfect vacuum environment) with a 32*27mm = 864mm = 0.000864m² tag you’d only be able to get 0.5 * (0.000864/(4*pi*2*2)) = 8.6uW.

It is therefore too bad that we can’t see in the presentation video what is inside the iFind, nor more details about the patent pending technologies involved. We hope that our dear readers will enlighten us in the comments section below.

Ask Hackaday: Auto Bed Leveling And High Temperature Force Sensitive Resistors

March 19, 2014 by Brian Benchoff 39 Comments

FSR

[Johann] over on the RepRap wiki has an ingenious solution for making sure a borosilicate glass bed is completely level before printing anything on his Kossel printer: take three force sensitive resistors, put them under the build platform, and wire them in parallel, and connect them to a thermistor input on an electronics board. The calibration is simply a bit of code in the Marlin firmware that touches the nozzle to the bed until the thermistor input maxes out. When it does, the firmware knows the print head has zeroed out and can calculate the precise position and tilt of the bed.

Great, huh? A solution to bed leveling that doesn’t require a Z-probe, uses minimal (and cheap) hardware, and can be retrofitted into just about any existing printer. There’s a problem, though: these force sensitive resistors are only good to 70° C, making the whole setup unusable for anything with a heated bed. Your challenge: figure out a way to use this trick with a heated bed.

The force sensitive resistors used – here’s a link provided by [Johann] – have a maximum operating temperature of 70° C, while the bed temperature when printing with ABS is around 130° C. The FSRs are sensitive to temperature, as well, making this a very interesting problem.

Anyone with any ideas is welcome to comment here, on the RepRap forums, the IRC, or anywhere else. One idea includes putting an FSR in the x carriage, but we’re thinking some sort of specialized heat sink underneath the bed and on top of the FSRs would be a better solution.

Video of the auto bed leveling trick in action below.

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Ask Hackaday: Wiping Your Bum With An Arduino?

March 9, 2014 by Brian Benchoff 83 Comments

Over or under? Standing or sitting? Truly, toilet paper has been the focus of the most irreconcilable arguments ever. The folks on the Arduino Stack Exchange have a far more important question: how do you trigger an alarm when your TP supply is low?

[user706837] asked the Internet this question in response to his kids never replacing an empty roll. This eliminates the most obvious means of notifying someone of an empty roll – looking at it before you sit down – and brings up a few interesting engineering challenges.

Most of the initial ideas deal with weight or some sort of light sensor that can differentiate between the white TP and the brown roll. A much, much more interesting solution puts a radioactive source in the TP holder’s spring-loaded rod and uses a sensor to detect how much TP is left. A quick back-of-the-wolfram calculation suggests this might be possible, and amazingly, not too dangerous.

We’re turning this one over to you, Hackaday readers. How would you design an empty toilet paper alarm? Bonus points awarded for ingenuity and cat resistance.

Image source, and also one of the longest and most absurd Wikipedia articles ever.

Ask Hackaday: What’s Up With This Carbon Fiber Printer?

January 29, 2014 by Brian Benchoff 40 Comments

The Hackaday Tip Line has been ringing with submissions about the Mark Forg3D printer, purportedly the, “world’s first 3D printer that can print carbon fiber.”

Right off the bat, we’re going to call that claim a baldfaced lie. Here’s a Kickstarter from a few months ago that put carbon fiber in PLA filament, making every desktop 3D printer one that can print in carbon fiber.

But perhaps there’s something more here. The Mark Forged site gives little in the way of technical details, but from what we can gather from their promo video, here’s what we have: it’s a very impressive-looking aluminum chassis with a build area of 12″x6.25″x6.25″. There are dual extruders, with (I think) one dedicated to PLA and Nylon, and another to the carbon and fiberglass filaments. Layer height is 0.1mm for the PLA and Nylon, 0.2mm for the composites. Connectivity is through Wifi, USB, or an SD card, with a “cloud based” control interface. Here are the full specs, but you’re not going to get much more than the previous few sentences.

Oh, wait, it’s going to be priced at around $5000, which is, “affordable enough for average consumers to afford.” Try to contain your laughter as you click the ‘read more’ link.

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