How Does A Voltage Multiplier Work?

March 22, 2017 by 43 Comments

If you need a high voltage, a voltage multiplier is one of the easiest ways to obtain it. A voltage multiplier is a specialized type of rectifier circuit that converts an AC voltage to a higher DC voltage. Invented by Heinrich Greinacher in 1919, they were used in the design of a particle accelerator that performed the first artificial nuclear disintegration, so you know they mean business.

Theoretically the output of the multiplier is an integer times the AC peak input voltage, and while they can work with any input voltage, the principal use for voltage multipliers is when very high voltages, in the order of tens of thousands or even millions of volts, are needed. They have the advantage of being relatively easy to build, and are cheaper than an equivalent high voltage transformer of the same output rating. If you need sparks for your mad science, perhaps a voltage multiplier can provide them for you.

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Hands-On Nvidia Jetson TX2: Fast Processing For Embedded Devices

March 14, 2017 by 74 Comments

The review embargo is finally over and we can share what we found in the Nvidia Jetson TX2. It’s fast. It’s very fast. While the intended use for the TX2 may be a bit niche for someone building one-off prototypes, there’s a lot of promise here for some very interesting applications.

Last week, Nvidia announced the Jetson TX2, a high-performance single board computer designed to be the brains of self-driving cars, selfie-snapping drones, Alexa-like bots for the privacy-minded, and other applications that require a lot of processing on a significant power budget.

This is the follow-up to the Nvidia Jetson TX1. Since the release of the TX1, Nvidia has made some great strides. Now we have Pascal GPUs, and there’s never been a better time to buy a graphics card. Deep learning is a hot topic that every new CS grad wants to get into, and that means racks filled with GPUs and CUDA cores. The Jetson TX1 and TX2 are Nvidia’s strike at embedded deep learning, or devices that need a lot of processing power without sucking batteries dry.

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The Tiko Printer: What Happens When You Innovate Too Much

February 27, 2017 by 76 Comments

Sometime in the very distant future, the Universe will become the domain of black holes. Energy and entropy will be compressed into minuscule quantum fluctuations. Even in this domain of nothingness, there will still be one unassailable truth: you should not buy a 3D printer on Kickstarter.

We’re no strangers to failed 3D printer crowdfunding campaigns. Around this time last year, backers for the Peachy Printer, an inordinately innovative resin printer, found out they were getting a timeshare in Canada instead of a printer. This was unusual not because a crowdfunding campaign failed, but because we know what actually happened. It’s rare to get the inside story, and the Peachy Printer did not disappoint.

For the last few months, we’ve been watching another crowdfunding campaign on its long walk to the gallows. The Tiko 3D printer is another 3D printer that looks innovative, and at the time of the crowdfunding campaign, the price couldn’t be beat. For just $179 USD, the backers of the Tiko printer would receive a 3D printer. Keep in mind the Tiko launched nearly two years ago, when a bargain-basement printer still cost about $400. Fools and money, or something like that, and the Tiko 3D printer campaign garnered almost three million dollars in pledges.

Now, after almost two years of development, Tiko is closing up shop. In an update posted to the Tiko Kickstarter this week, Tiko announced they are laying off their team and winding down operations. It’s a sad but almost predictable end to a project that could have been cool. Unlike so many other failed crowdfunding campaigns, Tiko has given us a post-mortum on their campaign. This is how the Tiko became a standout success on Kickstarter, how it failed, and is an excellent example of the difference between building one of something and building ten thousand.

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Ask Hackaday: What Can You Do With Origami?

February 26, 2017 by 43 Comments

At some point, most of us have learned a little of the ancient art of origami. It’s a fascinating art form, and being able to create a recognizable model by simply folding paper in the right order can be hugely satisfying. Most of us move on to other pursuits once we master the classic crane model, but the mathematics behind origami can lead some practitioners past the pure art to more practical structures, like this folding ballistic barrier for law enforcement use.

The fifty-pound Kevlar and aluminum structure comes from Brigham Young University’s College of Mechanical Engineering, specifically from the Compliant Mechanisms Research program. Compliant mechanisms move by bending or deflecting rather than joints between discrete parts, and this ballistic shield is a great example. The mechanism is based on the Yoshimura crease pattern, which can be quickly modeled with a piece of paper. Scaling that up to a full-sized structure, light enough to be fielded but strong enough to stop a .44 Magnum round, was no mean feat. But as the video below shows, the prototype has a lot of potential.

Now it’s your turn: what applications have you seen for compliant mechanisms? Potential applications range in scale from MEMS linkages for microinjecting cells to huge antennas that unfurl in orbit. We’ve featured a few origami-like structures before, like this self-assembling robot or a folding quadcopter, but neither of these really rates as compliant. This elegant parabolic satellite antenna is more like it, though. There are applications for designing origami and a mathematical basis for the field; has anyone tried using these tools to design compliant structures? Sound off in the comments below.

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40-Acre HAARP Rides Again, And They Want You To Listen

February 18, 2017 by 62 Comments

News comes to us this week that the famous HAARP antenna array is to be brought back into service for experiments by the University of Alaska. Built in the 1990s for the US Air Force’s High Frequency Active Auroral Research Program, the array is a 40-acre site containing a phased array of 180 HF antennas and their associated high power transmitters. Its purpose it to  conduct research on charged particles in the upper atmosphere, but that hasn’t stopped an array of bizarre conspiracy theories being built around its existence.

The Air Force gave up the site to the university a few years ago, and it is their work that is about to recommence. They will be looking at the effects of charged particles on satellite-to-ground communications, as well as over-the-horizon communications and visible observations of the resulting airglow. If you live in Alaska you may be able to see the experiments in your skies, but residents elsewhere should be able to follow them with an HF radio. It’s even reported that they are seeking reports from SWLs (Short Wave Listeners). Frequencies and times will be announced on the @UAFGI Twitter account. Perhaps canny radio amateurs will join in the fun, after all it’s not often that the exact time and place of an aurora is known in advance.

Tinfoil hat wearers will no doubt have many entertaining things to say about this event, but for the rest of us it’s an opportunity for a grandstand seat on some cutting-edge atmospheric research. We’ve reported in the past on another piece of upper atmosphere research, a plan to seed it with plasma from cubesats, and for those of you that follow our Retrotechtacular series we’ve also featured a vintage look at over-the-horizon radar.

HAARP antenna array picture: Michael Kleiman, US Air Force [Public domain], via Wikimedia Commons.

Building Homebrew VTOL Rockets

February 16, 2017 by 35 Comments

No one can deny what SpaceX and Blue Origin are doing is a feat of technological wizardry. Building a rocket that takes off vertically, goes into space, and lands back on the pad is an astonishing technical achievement that is literally rocket science. However, both SpaceX and Blue Origin have a few things going for them. They have money, first of all. They’re building big rockets, so there’s a nice mass to thrust cube law efficiency bump. They’re using liquid fueled engines that can be throttled.

[Joe Barnard] isn’t working with the same constraints SpaceX and Blue Origin have. He’s still building a rocket that can take off and land vertically, but he’s doing it the hard way. He’s building VTOL model rockets. Most of the parts are 3D printed. And he’s using solid motors you can buy at a hobby shop. This is the hard way of doing things, and [Joe] is seeing some limited success with his designs.

While the rockets coming out of Barnard Propulsion Systems look like models of SpaceX’s test vehicles, there’s a lot more here than looks. [Joe] is using a thrust vectoring system — basically mounting the Estes motor in a gimbal attached to a pair of servos. This allows the rockets to fly straight up without fins or even the launch rod used to get the rocket up to speed in the first few millseconds of flight. This is active stabilization of a model rocket, with the inevitable comments of ITAR violations following soon afterward.

Taking off vertically is one thing, but [Joe] is also trying to land his rockets vertically. Each rocket he’s built has a second Estes motor used only for landing. During descent, the onboard microcontroller calculates the speed, altitude, and determines if it’s safe to attempt a vertical landing. If the second motor has sufficient impulse to make velocity and altitude equal zero at the same time, the landing legs deploy and the rocket hopefully makes a soft touchdown in the grass.

While [Joe] hasn’t quite managed to pull off a vertical takeoff and landing with black powder motors quite yet, he’s documenting and livestreaming all of his attempts. You can check out the latest one from a week ago below.

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Turbine-driven Robot To Navigate Inside Space Station

February 14, 2017 by 23 Comments

It may look more like a Companion Cube than R2-D2, but the ISS is getting an astromech droid of sorts.

According to [Trey Smith] of the NASA Ames Research Center, Astrobee is an autonomous robot that will be able to maneuver inside the ISS in three dimensions using vectored thrust from a pair of turbines. The floating droid will navigate visually, using a camera to pick out landmarks aboard the station, including docking ports that let it interface with power and data. A simple arm allows Astrobee to grab onto any of the hand rails inside the ISS to provide a stable point for viewing astronaut activities or helping out with the science.

As cool as Astrobee is, we’re intrigued by how the team at Ames is testing it. The droid is mounted on a stand that floats over an enormous and perfectly flat granite slab using low-friction CO₂ gas bearings, giving it freedom to move in two dimensions. We can’t help but wonder why they didn’t suspend the Astrobee from a gantry using a counterweight to add that third dimension in. Maybe that’s next.

From the sound of it, Astrobee is slated to be flight ready by the end of 2017, so we’ll be watching to see how it does. But if they find themselves with a little free time in the schedule, perhaps adding a few 3D-printed cosmetics would allow them to enter the Hackaday Sci-Fi Contest.