Monday, October 31
Sort Your Candy With A Raspberry Pi And Google Cloud Vision
If you have been off trick-or-treating and returned home with an embarassment of candy, what on earth can you do to mange the problem and sort it by brand?
Yes, it’s an issue that so many of us have had to face at this time of year. So much a challenge, that the folks at [Dexter Industries] have made a robotic candy-sorter to automate the task.
OK, there’s something of the tongue-in-cheek about the application. But the technology they’ve used is interesting, and worth a second look. Hardware wise it’s a Lego Mindstorms conveyor and hopper controlled by a Raspberry Pi through the BrickPi interface. All very well, but it’s in the software that the interest lies. They use the Raspberry Pi’s camera to take a picture to send off to Google Cloud Vision, which they then query to return a guess at the brand of the candy in question. The value returned is then compared to a list of brands to keep or donate to another family member, and the hopper tips the bar into the respective pile. They provide full build details and code, as well as the video we’ve put below the break. So simple a child can explain it, sort of.
Machine vision remains a challenge, as we can see from our list of stories tagged with it; only a few of them over all the years Hackaday has been in existence. Using a cloud service might not be to everyone’s taste, but it provides an alternative route into machine vision as well as the extra power of the Google engine, and could open up the technology to makers who might not otherwise use it.
[via Recantha]
Filed under: Raspberry Pi
Quick Tip: Know Your Screwdrivers (Hint: It’s Not Called a “Flathead!”)
The post Quick Tip: Know Your Screwdrivers (Hint: It’s Not Called a “Flathead!”) appeared first on Make: DIY Projects and Ideas for Makers.
Building Transistors with Transistors
Since the 1940s when the first transistor was created, transistors have evolved from ornery blocks of germanium wrangled into basic amplifiers into thousands and thousands of different devices made of all kinds of material that make any number of electrical applications possible, cheap, and reliable. MOSFETs can come in at least four types: P- or N-channel, and enhancement or depletion mode. They also bear different power ratings. And some varieties are more loved than others; for instance, depletion-mode, N-channel power MOSFETs are comparatively scarce. [DeepSOIC] was trying to find one before he decided to make his own by hacking a more readily available enhancement-mode transistor.
For those not intimately familiar with semiconductor physics, the difference between these two modes is essentially the difference between a relay that is normally closed and one that’s normally open. Enhancement-mode transistors are “normally off” and are easy to obtain and (for most of us) useful for almost all applications. On the other hand, if you need a “normally on” transistor, you will need to source a depletion mode transistor. [DeepSOIC] was able to create a depletion mode transistor by “torturing” the transistor to effectively retrain the semiconductor junctions in the device.
If you’re interested in semiconductors and how transistors work on an atomic level, [DeepSOIC]’s project will keep you on the edge of your seat. On the other hand, if you’re new to the field and looking to get a more basic understanding, look no further than these DIY diodes.
Filed under: hardware
The Potowitzer: A Rapid Fire Potato Cannon
If you’ve ever fired a potato cannon, you’ll know that they are a raucous good time, but are somewhat clumsy to reload after each shot. Seeing an opportunity to improve on the design and minimize the delay between launches, [Danger First] have concocted a fast reloading potato cannon — or should I say — Potowitzer.
The key here is that they’ve gone through the extra effort of designing and building honest-to-goodness artillery rounds for their Potowitzer’s manual breech-loading mechanism. Foregoing the inconsistency of potatoes, they’ve 3D printed a bevy of bullets and sealed them with propane gas into PVC pipe cartridges. Metal contacts around the base to carry current from a BBQ lighter to the inside of the cartridge to ignite the propellant. Seeing it fire at about 18 rounds per minute is something special.
This home-made piece of artillery looks like a blast to fire. The only issue appears to be that the rapid salvos are offset by the necessity of fabricating more ammunition — something that isn’t an issue with regular potato cannons. Remember to exercise all necessary precautions if you plan on using any kind of combustible.
If you want to get an idea of what’s going in inside these rounds — or the chamber of a regular potato cannon — check out this tennis ball cannon with a clear combustion chamber.
[Thanks for the submission, Ivan Owen!]
Filed under: 3d Printer hacks, weapons hacks
By the Glow of the CRT
If you are a certain age, you probably remember writing software (or playing Adventure) bathed in an amber or green light from an old CRT terminal. If you are even older, you might have found it way better than punching cards, but that’s another story. [Tobi] wanted to relive those days (well, sounds like he is too young to have lived them to start with) so he hooked up a VT220 terminal to his Linux box.
This isn’t that surprising. Linux’s forefather, Unix, expected these kind of terminals (or a hard copy TeleType) and all the trappings for working with a glass terminal are still in there. You do have to deal with a few configuration items that [Tobi] works through.
In fact, it appears that he wrote his blog post using vi on that very VT220 using a text-based Web browser to research the links. He has a lot of resources for connecting a terminal of any sort (or even a terminal emulator) to a Linux computer.
There’s been a lot of interest in old terminals lately. You see a lot of old VT100s lying around. I personally have an ADDS Regent 100 that occasionally connects to several of my computers. You can see it in the video below.
Filed under: linux hacks
Punk Those Trick-or-Treaters with a 3D Radar Booby Trap
The post Punk Those Trick-or-Treaters with a 3D Radar Booby Trap appeared first on Make: DIY Projects and Ideas for Makers.
Build a NeoPixel Ninja Mask with Particle Photon
The post Build a NeoPixel Ninja Mask with Particle Photon appeared first on Make: DIY Projects and Ideas for Makers.
Mechanical Music Boxes Mix MIDI with Marbles
The post Mechanical Music Boxes Mix MIDI with Marbles appeared first on Make: DIY Projects and Ideas for Makers.
Pro Tip: Techniques to Make Halloween Makeup Last Through the Night
The post Pro Tip: Techniques to Make Halloween Makeup Last Through the Night appeared first on Make: DIY Projects and Ideas for Makers.
Put That Amateur Radio License to Use on 915 MHz
Amateur radio enthusiasts in the US will be interested in Faraday, an open-source digital radio that runs on 915 MHz, which amateur radio enthusiasts may know better as the 33 cm band.
You can transmit on 915 MHz without a license (in the US), taking advantage of the Industrial, Scientific, and Medical (ISM) exemption. This means that there’s commodity hardware available for sending and receiving, which is a plus. But you can’t do so with any real power unless you have an amateur radio license. And that’s what makes Faraday interesting — it makes it very easy to transmit and receive digital data, with decent power and range, if you’re licensed. The band is currently under-utilized, so go nuts!
The hardware design and documentation is online, and so is the firmware. The founders of the project would like you to build out a big network of these devices, possibly meshing them together. Our only regret is that the 33 cm band is only really open for use in the US, both with a license and without. Of course, there’s very little the Faraday team can do about that.
We’re no strangers to digital-mode amateur radio around here. But if you’re an amateur who hasn’t played around with digital modes yet, this might be a good way to get your feet wet.
Thanks to [Daniel] for the tip!
Filed under: radio hacks
Making VR A Little More Usable With A Pinch Gesture Ring
[Florian] wants to browse the web like an internet cowboy from a cyberpunk novel. Unfortunately, VR controllers are great for games but really incapacitate a hand for typing. A new input method was needed, one that would free his fingers for typing, but still give his hands detailed input into the virtual world.
Since VR goggles have… hopefully… already reached peak ridiculousness, his first idea was to glue a Leap Motion controller to the front of it. It couldn’t look any sillier after all. The Leap controller was designed to track hands, and when combined with the IMU built into the VR contraption, did a pretty good job of putting his hands into the world. Unfortunately, the primary gesture used for a “click” was only registering 80% of the time.
The gesture in question is a pinching motion, pushing the thumb and middle finger together. He couldn’t involve a big button without incapacitating his hands for typing. It took a few iterations, but he arrived at a compact ring design with a momentary switch on it. This is connected to an Arduino on his wrist, but was out of the way enough to allow him to type.
It’s yet another development marching us to usable VR. We personally can’t wait until we can use some technology straight out of Stephenson or Gibson novel.
Filed under: Virtual Reality
Forget Wifi or Bluetooth, Pair Directly With Your Phone’s Speaker
[Kedar Nimbalkar] hyperbolically advertises the ultimate cell phone speaker dock. It costs a dollar. It doesn’t need you to pair with it via Bluetooth or WiFi. It pairs extremely fast, 0.000000000001, he clarifies. It may also look like a broken laptop speaker with a stomped wall wart soldered to it, but who can keep up with industrial design trends these days?
He shows us the device in operation. He starts playing some music on his phone’s speaker. It’s not very loud, so he simply lays the phone on the dock. Suddenly, all the audio fidelity a Dell Lattitude from the 90s can provide erupts from the device! How is this done?
Of course, there’s not much to the trick. Since the cellphone speaker is a coil it can induce a small current in another coil. The resulting voltage can be picked up by an audio amplifier and played through the speakers. Nonetheless it’s pretty cool, and we like his suggestion of betting our friends that we could wirelessly pair with their ear buds. Video after the break.
A coil can pick up a lot more sounds than you might expect – check out the Elektrosluch to learn more. If you want to learn more about coils and coupling, check out [James’] simulation.
Filed under: home entertainment hacks, wireless hacks
Phone-To-Phone Power Theivery
Once again, [Rulof]’s putting his considerable hacking abilities to good use, his good use that is. By modding a few simple parts he’s put together something that he can carry around on his keychain that’ll allow him to steal power from his friend’s phones to charge his own phone.
He starts by cutting away the motor from an iPhone fan to isolate the Micro USB connector. He then removes the charging circuit board from a cheap Chinese USB power bank, and solders wires from the Micro USB connector to one side of the board. Lastly, he cuts away the Lightning connector from a Lightning-to-USB cable and solders that connector to the other side of the circuit board. For longevity and cosmetics, he puts it all in a small wood block and connects a key ring. The result is a small, neat looking box with a Micro USB connector on one side and a Lightning connector on the other. You can see him make it, and then use it to steal power from his friends in the video after the break.
And as long as his friends don’t catch on, he’ll never be without a power source again. But if they do catch on, he could always turn an ATX computer power supply into an 8 USB port charging station and win his friends back by charging all their phones. And what if there just isn’t any power because you’re city’s been hit with a cyclone? For that, one very capable hacker has built a hand cranked phone charger.
Filed under: Cellphone Hacks, iphone hacks
How to Make Beautiful Midori-Style Traveler’s Notebooks
The post How to Make Beautiful Midori-Style Traveler’s Notebooks appeared first on Make: DIY Projects and Ideas for Makers.
Sunday, October 30
Hackaday Links: October 30, 2016
Diablo. Mech Warrior. Every LucasArts game. There are reasons to build an old PC, and no, emulation cannot completely capture the experience of playing these old games. [Drygol] set out to create a retro PC and succeeded brilliantly. The built features an old desktop AT case (when is the last time you saw one of them?), a 233MHz Pentium with MMX technology, an ancient PCI video card, and an old ISA Ethernet card (with AUI connector). Incoming upgrades will be an ATI 3D Rage PRO, PCI SoundBlaster, and hopefully Windows 98SE.
Right now, we’re gearing up for the Hackaday Superconference next weekend. It’s going to be awesome, and we’re going to announce the winner of the Hackaday Prize. We have another contest going on right now – the Enlightened Raspberry Pi Contest. The name of the game here is documentation. Build something, document it on hackaday.io, and you get some cool prizes.
It’s no secret to Hackaday readers that I’m a gigantic dumbass. A few weeks ago, I speculated Espressif’s ESP32 module won’t see out of stock issues unless someone figures out how to run a Nintendo emulator on it. [Sprite_tm] took this as a challenge and put an NES emulator on an ESP32 dev board as a test. Now, [Derek Lai] built the WiFiBoy32, a very simple PCB with a few buttons, speaker, LCD screen, and an ESP32 module built just to play old Nintendo games. Great, now the ESP32 will see Raspberry Pi Zero levels of adoption.
The VoCore is a tiny router SoC-based Linux computer that’s an acceptable solution in some cases. We’ve seen a few tutorials, and a few people playing Doom on it. Now there’s a VoCore2 on IndieGogo. There are two models, The VoCore 2 and VoCore 2 Lite, with the Lite model available for $4 + shipping. That’s really cheap, even if the ‘tiny board that runs Linux for under $10’ market is getting a little crowded.
@mwichary got lost in Spain and stumbled upon something fantastic. Instead of following the signs for the Dali museum, he found another sign for the ambiguously named Museu de la Tecnica. What was inside? The greatest collection of typewriters on the planet. There’s the original Sholes typewriter, a weird two-keyboard typewriter, a dual typewriter, bizarre ball typewriters, everything is typewriters, and it’s all in a tiny, tiny town in Spain. Thanks [Beth] for the tip.
The ATtiny85 is the new 555. Want proof? Here’s a ring watch, constructed out of nothing but some perf board, a few resistors, buttons, and an OLED. The ATtiny85 is the only active component in the project.
Your input requested. This is the Hackaday Retro Edition. Currently, it displays five random Hackaday posts every five minutes, stripped of all JavaScript, CSS, and Web 2.0 cruft. The idea is to make a destination on the Internet that is accessible from every computer, from Commodore 64s to computers running an Intel 4004 (this is possible, and it happened). The Retro Edition is my baby, and over the next few months, I’m going to take some time to fix it up. What would you like to see in an updated Hackaday Retro Edition?
Filed under: Hackaday Columns, Hackaday links
Just In Time For Christmas! A DIY Desktop LED Tree
Okay, we haven’t even hit Halloween yet, but if you’re planning some kind of holiday project, now’s a good time to start ordering your parts, especially if you’re designing your own PCB. While there’s no PCB involved, [designer2k2] built a desktop “hollow” Christmas tree using some WS2812 RGB LEDs controlled by a microcontroller and powered by USB.
The board running [designer2k2]’s project is a Digispark, a USB powered board by Digistump which contains an ATtiny85. The LEDs, four different sized NeoPixel rings, plus a single pixel for the top, are connected together using some solid wire which makes for a very cool look. The code that runs on the ATtiny is the part that really makes this tree. The code cycles through colors and some light chaser effects, as well as a mode that shows a green tree with some white lights. The whole project is topped off by a routine that spells “XMAS” as you look at the tree from the top down.
We’ve seen some other Christmas tree hacks over the years controlled by various things, but this one is a fairly simple, cool design. [Designer2k2] also released the code for the tree and I’m sure a lot of us could come up with some more light designs.
Check out the video after the break:
Filed under: ATtiny Hacks, Holiday Hacks
Robotic Farming, Aussie Style
Australian roboticists from the Queensland University of Technology have developed a prototype agricultural robot that uses machine vision to identify both weed and crop plants before either uprooting or poisoning the weeds or applying fertiliser to the crop.
The machine is a wide platform designed to straddle a strip of the field upon which it is working, with electric wheel motors for propulsion. It is solar-powered, and it is envisaged that a farm could have several of them continuously at work.
At a superficial level there is nothing new in the robot, its propulsion, or even the plant husbandry and weeding equipment. The really clever technology lies in the identification and classification of the plants it will encounter. It is on the success or failure of this in real farm environments that the robot’s future will hinge. The university’s next step will be to take it on-farm, and the ABC report linked above has a wonderfully pithy quote from a farmer on the subject. You can see the machine in action in the video below the break.
Farming robots have a significant following among the hardware hacker community, but it is possible that the machine-vision and plant-identifying abilities of this one would be beyond most hackers. However it is still an interesting project to watch, marking as it does a determined attempt to take the robot out of the lab and into real farm settings.
We’ve covered farming robots a few times in the past here at Hackaday. Gantry-based robots like Farmbot, the walking hexapod Prospero robot farmer, or a further six-legged robot also called Farmbot. Practical farming robots have been a little more rare though, with a Canadian autonomous John Deere tractor made not by engineers but by a farmer being one of the most promising.
Thanks [muA] for the tip.
Filed under: robots hacks
Projection Mapping in Motion Amazes
Projection mapping is pretty magical; done well, it’s absolutely miraculous when the facade of a building starts popping out abstract geometric objects, or crumbles in front of our very eyes. “Dynamic projection mapping onto deforming non-rigid surface” takes it to the next level. (Watch the video below.)
A group in the Ishikawa Watanabe lab at the University of Tokyo has a technique where they cover the target with a number of dots in an ink that is only visible in the infra-red. A high-speed (1000 FPS!) camera and some very fast image processing then work out not only how the surface is deforming, but which surface it is. This enables them to swap out pieces of paper and get the projections onto them in real time.
Make sure that you do watch the video. The bit where they aim a fan at the projection-mapped T-shirt, and the dancing animated Stanford Bunny flaps in the breeze along with it is truly amazing.
Want more of the projection-mapping craze of the early 2010’s? Check out this post on projection mapping with industrial robot arms, or a projection mapped sandbox. If that’s not enough for you, have a look at this footage from [Amon Tobin]’s live tour in 2012.
Thanks [Stuart] for the tip!
Filed under: video hacks
This Week in Making: Waterjet Jack-O’-Lanterns and the Truth About Wireless Power
The post This Week in Making: Waterjet Jack-O’-Lanterns and the Truth About Wireless Power appeared first on Make: DIY Projects and Ideas for Makers.
Ultra-Polished, Handmade Settlers of Catan Redux
[Fuzzy Wobble] and [Amy Wang]’s Deep Space Settlers project is a one-of-a-kind re-invention of the popular board game Settlers of Catan, and showcases the polished results that are possible with the fabrication tools and methods available in many workshops and hackerspaces today. We reached out to the makers for some of the fabrication details, which they were happy to share.
(For those of you who are familiar with the game, technically this is a remake and slight evolution of the Seafarers expansion to the base Settlers of Catan game. A few rule changes were made, but it is mostly a total remodel and redesign.)
The project page doesn’t talk much about the fabrication process, but laser-cut plastic is a major component. The tiles are black acrylic hexagons with circular pieces attached. The circular pieces are made from different translucent colors (which vendors often call ‘fluorescent’ colors) except for the gold, which is a gold-mirrored acrylic. They are engraved on the bottom, which gives the patterns their frosty white etched appearance. Mounted with the etched side downward onto the black hexagons, the contrast really makes the design pop. The cities are two-piece acrylic assemblies made in a variety of translucent colors, and the larger trophies are laser-engraved on both sides; text on front, pattern on back.
[Fuzzy Wobble] kindly provided Hackaday with some additional details on the methods and materials used:
- Hex pieces were all laser cut and etched on acrylics. They were attached using a double-sided tape.
- The resource cards were made with layers of premium paper. Gloss ink was used to print on the matte paper for the text and textured backs.
- The patterns on the backs of the development cards were created using silver foiling. “A tricky process that produces astonishing results given how simple it is.”
- The numbered markers were created using acrylic hemispheres, and again, silver foiling. “The numbers were without a doubt the most tedious part of the project and had to be done by hand in a way that there were no imperfections, otherwise they would be magnified by the lens effect of the hemisphere.”
- The player pieces were made with the laser cutter with various colors of tint acrylic.
- The box was internally partitioned with laser-cut acrylic.
- The perimeter pieces are 1/4″ acrylic, and backed with high friction material to ensure the board cannot slide out of alignment.
It’s clear that the builders of this project know what they’re doing. However, using a tool well only gets you part way. It’s one thing to etch a pattern or cut some acrylic, but it’s another thing to etch or cut that plastic then attach it onto something else without showing a single glue smudge, fingerprint, or scratch on the end result. Even if you start with quality parts, experience and attention to detail (and the patience and willingness to apply both) is what will separate a hack job from a polished end product. We certainly know there are plenty of ways to fail at laser cutting.
As for the other methods mentioned (like silver foiling), do any of you have experience using those processes to get sharp-looking end results? Any tips to share? Let us know in the comments!
Filed under: misc hacks
America’s largest gaming museum: Rare games, crazy prototypes, and giant Pong
FRISCO, Texas—Finally, there's a museum made for people like me.
The National Videogame Museum (yes, they spell it as one word) has been open since April of this year in the Dallas-area suburb of Frisco, and it houses an incredible collection of gaming memorabilia. The rarest cartridges, systems, and prototypes are all here, protected as if they were the Mona Lisa (and for some game collectors, they may as well be). Come here to marvel at one-of-a-kind finds like a Nintendo World Championship cartridge, a mint-condition Ultra Hand toy, or the only known white-molded Atari 2600 in the world.
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Litter Basket Automation
Sometimes the technology part of a project isn’t the hard part. It is having an idea for something both useful and doable. Sure, a robot butler that would do your cleaning and laundry would be useful, but might be out of reach for most of us. On the other hand, there’s only so many use cases for another blinking LED.
[Martinhui] knows how to use an ultrasonic sensor with an Arduino. Driving a motor isn’t that hard, either. The question is: what do you do with that? [Martin’s] answer: Automate a trash can. You can see a video of the result, below.
You can find commercial versions of this, of course, but what fun is that? The can is a bit small, but a larger motor or a different mechanical design could scale it up easily.
As robotic trash cans go, this isn’t that ambitious, but it is highly doable. If only it connected to the Internet.
Filed under: Arduino Hacks
Primer on Servos Hits All the Basics
Servos are pretty basic fare for the seasoned hacker. But everyone has to start somewhere, and there’s sure to be someone who’ll benefit from this primer on servo internals. Who knows – maybe even the old hands will pick up something from a fresh perspective.
[GreatScott!] has been building a comprehensive library of basic electronics videos over the last few years that covers everything from using a multimeter to programming an Arduino. The last two installments delve into the electromechanical realm with a treatment of stepper motors along with the servo video below. He covers the essentials of the modern RC-type servo in a clear and engaging style that makes it easy for the newbie to understand how a PWM signal can translate into positional changes over a 180° sweep. He shows how to control a servo directly with an Arduino, with bonus points for including a simple 555-based controller circuit too. A quick look at the mods needed to convert any servo to continuous rotation wraps up the video.
If [GreatScott!]’s video whets your appetite for more, be sure to check out [Richard Baguley]’s deeper dive into servos. And when you’re ready to put your new-found knowledge into practice, maybe a nice project would be to convert a hobby servo into a linear actuator.
Filed under: classic hacks, misc hacks
A Virtual Glimpse Into The Forest
Taking a stroll through the woods in the midst of autumn is a stunning visual experience. It does, however, require one to live nearby a forest. If you are one of those who does not, [Koen Hufkens] has recently launched the Virtual Forest project — a VR experience that takes you though a day in a deciduous forest.
First off, you don’t need a VR apparatus to view the scenery. Web-browsers and most smart phones are capable of displaying the 360 degree images. The Raspberry Pi 2-controlled Ricoh Theta S camera is enclosed in a glass lamp cover and — with the help of some PVC pipe — mounted on a standard fence post. Power is delivered ingeniously via a Cat5e cable, and a surge protector has also been included in case of lightning strikes. Depending on when you view the website, you could be confronted with a black screen, or a kaleidoscope of color.
The project’s goal is to track the timing of seasonal changes in North-Eastern forests. If you’re interested in setting up a similar system, the build and a parts breakdown can be found here while the code is available on Github. If the cost of the Theta S camera is prohibitive, then you can make your own panoramic camera to keep your build on track.
[Thanks for the submission, Koen Hufkens!]
Filed under: digital cameras hacks, Raspberry Pi, Virtual Reality
Vintage Radio Transformed into Custom PC Case
We see a lot of old radio restoration projects around here, and we have to admit to having mixed emotions about some of them. It seems a shame to go through the effort to lovingly restore a vintage Art Deco case only to stuff it with a Raspberry Pi and Bluetooth. Seems like if you’re going to restore a radio, go all the way and bring the original electronics back to life. But this radio “restoration” avoids that issue altogether by cleverly concealing a full PC build in a vintage radio case.
You don’t have to go far in the Hackaday Wayback machine to find an antique radio with updated audio, but we’re pretty sure this is the first antique radio PC case mod we’ve seen. Nicely done, [Solomon]!
[via r/DIY]
Filed under: classic hacks, misc hacks
Easy UFO Lights on your Drone for Halloween
Sometimes it’s not so much what you put together, it’s how you use it. The folks at Adafruit have put up a project on how to dress up your drone with ‘UFO lights’ just in time for Halloween. The project is a ring of RGB LEDs and a small microcontroller to give any quadcopter a spinning ‘tractor beam light’ effect. A 3D printed fixture handles attachment. If you’re using a DJI Phantom 4 like they are, you can power everything directly from the drone using a short USB cable, which means hardly any wiring work at all, and no permanent changes of any kind to the aircraft. Otherwise, you’re on your own for providing power but that’s probably well within the capabilities of anyone who messes with add-ons to hobby aircraft.
One thing this project demonstrates is how far things have come with regards to accessibility of parts and tools. A 3D printed fixture, an off-the-shelf RGB LED ring, and a drop-in software library for a small microcontroller makes this an afternoon project. The video (embedded below) also demonstrates how some unfamiliar lights and some darkness goes a long way toward turning the otherwise familiar Phantom quadcopter into a literal Unidentified Flying Object.
While it might be tempting to buzz people to show off the effect on Halloween, flying over or around people with what is essentially an airborne surprise blender is a needless risk. But you don’t need people around; drones (and some cleverness) have opened many doors for the amateur film crowd.
Filed under: led hacks
Saturday, October 29
Build the Simplest Bipolar Power Supply
How many integrated circuits do you need to build up a power supply that’ll convert mains AC into a stable DC voltage? Would you believe, none? We just watched this video by [The Current Source] (embedded below), where he builds exactly that. If you’re in the mood for a very well done review of diode bridges as well as half- and full-wave rectifiers, you should check it out.
First off, [TCS] goes through the basics of rectification, and demonstrates very nicely on the oscilloscope how increasing capacitance on the output smooths out the ripple. (Hint: more is better.) And then it’s off to build. The end result is a very simple unregulated power supply — just a diode bridge with some capacitors on the output — but by using really big capacitors he gets down into the few-millivolt range for ripple into a constant load.
The output voltage of this circuit will depend on the average current drawn, but for basically static loads this circuit should work well enough, and the simplicity of just tossing gigantic capacitors at the problem is alluring. (We would toss in a linear regulator somewhere.)
Quibbling over circuit designs isn’t why you’re watching this video, though. It’s because you want to learn something. Check out the rest of his videos as well. [TCS] has only been at it a little while, but it looks like this is going to be a channel to watch.
Filed under: misc hacks
Living off the Grid, on Water Power
When you think of living off the grid, you often think of solar power. But if you’ve got a good head, and enough flow, water power can provide a much more consistent flow of electrons. All it requires is a little bit of engineering, epic amounts of manual labor, and some tricks of the trade, and you’ll have your own miniature hydroelectric power plant.
[Homo Ludens], the playful ape, has what looks like a fantastic self-sufficient home/cabin in a beautiful part of Chile. His webpages are a tremendous diary of DIY, but the microhydro plant stands out.
You might expect that building a hydro plant involves a lot of piping, and trenching to lie that pipe in, but the exact extent, documented in many photos, is sobering. At places, the pipe needed to be bent, and [Homo Ludens] built a wire-mesh pipe heater to facilitate the work — with the help of a few friends to weigh the pipe down at either end and create the bend. The self-wound power transformer is also a beauty.
There’s a lot more detail here than we can possibly get into, so go check it out. And if you’re in the mood for more hydro, we’ve recently run a writeup of a less ambitious, but still tidy, project that you should see. Or you could just rip apart an old washing machine.
Thanks [Patrick] for the great tip!
Filed under: green hacks
Diamonds are for Data Storage
Most data storage devices we currently use are, at their core, two-dimensional. Sure, a hard drive might have multiple platters, but the data storage takes place on a flat surface. Even an optical drive is effectively a single surface that holds data. At the City College of New York, they are experimenting with storing data in three dimensions using lab-grown diamonds and LASERs.
Usually, diamonds that have few flaws are more valuable. But in this application, the researchers exploit the flaws to store information. Optical memory that uses a volume instead of a surface isn’t exactly new. However, it is difficult to use these techniques in a way that is rewritable.
Diamonds are a crystalline structure of carbon atoms. Sometimes, though, a carbon atom is missing from the structure. That’s a vacancy. Another defect is when a nitrogen atom replaces a carbon atom. Sometimes a vacancy occurs next to a rogue nitrogen atom and that causes an NV (nitrogen vacancy) center.
It turns out these NV centers are exploitable in several ways ranging from magnetic resonance detection to quantum mechanics experiments. The NV centers can trap an electron, but can also be forced to release a trapped electron. This allows you to treat an NV center with or without an electron as a binary one or zero.
A green LASER can inject an electron into an NV center. A red LASER at low power can determine if an electron is present. At higher powers, the red LASER will eject an electron from an NV center if it is present. If the diamond is in total darkness, the memory state will persevere “virtually forever” according to the researchers (we guess diamonds really are forever).
Of course, the LASER beams are larger than the single-atom defects, but the researchers actually use that to their advantage. By controlling the duration of the LASER pulse, a particular number of NV centers can be charged. That allows a single pulse to store or read multiple bits of data. For example, if the volume contained four NV centers, the volume could represent two bits of information. Since the diamonds are created in a lab, the concentration of NV centers is deterministic.
Currently, the device can store data at a density that exceeds a DVD by about 100 times. However, they are working on ways to get even more dense storage.
We’ve seen glass storage before. You have to wonder if this has applications with 3D ICs, as well.
Photo Credit: [Siddharth Dhomkar] and [Jacob Henshaw] CC BY-ND
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From Poop to cat meeples, the most unusual new board games
Welcome to Ars Cardboard, our weekend look at tabletop games. Check out our complete board gaming coverage at cardboard.arstechnica.com.
At the recent Essen board game fair—the hobby's biggest event—we saw 1,000+ new titles. That meant we also saw our fair share of amazing new games. We also saw plenty of titles that were strange, unusual, and/or poop-focused. These are those games.
Don't let anyone tell you that this isn't board gaming's "Golden Age."
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