Many of us have gone on a stationary romp through some virtual or augmented scape with one of the few headsets out in the wild today. While the experience of viewing a convincing figment of reality is an exciting sensation in itself, [Mark Lee] and [Kevin Wang] are figuring out how to tie other senses into the mix.
The duo from Cornell University have built a mechanical exoskeleton that responds to light with haptic feedback. This means the wearer can touch the sphere of light around a source as if it were a solid object. Photo resistors are mounted like antenna to the tip of each finger, which they filed down around the edges to receive a more diffused amount of light. When the wearer of the apparatus moves their hand towards a light source, the sensors trigger servo motors mounted on the back of the hand to actuate and retract a series of 3D printed tendons which arch upward and connect to the individual fingers of the wearer. This way as the resistors receive varying amounts of light, they can react independently to simulate physical contours.
One of the goals of the project was to produce a working proof of concept with no more than 100 dollars worth of materials, which [Mark] and [Kevin] achieve with some cash to spare. Their list of parts can be found on their blog along with some more details on the project.
Filed under: Virtual Reality
Imagine a camera that took encrypted pictures. If your camera is stolen, the only thing on the memory card would be random data that can only be unlocked with a key. If you hire a photographer, those images cannot be copied without the key. At the very least, it’s an interesting idea made impressive because this actually exists.
[Doug] recently got his hands on a Samsung NX300, a nice camera for the price that conveniently runs Linux and is kinda open-sourced by Samsung. With special firmware, [Doug] created public/private key encryption for this camera, giving only the person with the private key the ability to unlock the pictures taken with this camera.
[Doug] started his build by looking at the firmware for this camera, figuring out how to take everything apart and put it back together. With a few modifications that included encryption for all images taken with this camera, [Doug] repackaged the firmware and upgraded the camera.
The encryption firmware is available on the site, but considering how easily [Doug] was able to make this hack happen, and a great walkthrough of how to actually do it raises some interesting possibilities. The NX300 is a pretty nice camera that’s a little bit above the Canon PowerShot cameras supported by CHDK. It also runs Linux, so if you’re looking for something cool to do with a nice camera, [Doug] has a very good resource.
Filed under: digital cameras hacks
Over in Russia there are a few people doing extremely in-depth technical teardowns, and the latest is one of the most ambitious ever seen. The PSXDEV team is tearing into the heart of the original PlayStation (Google translatrix), looking at 300,000 transistors, and re-implementing the entire console in a logic level simulator.
While the CPU in the PSX is unique to that specific piece of hardware, a lot of this custom silicon can be found in other places. The core – a RISC LSI LR33300 – is documented in a few rare tomes that are somehow available for free on the Internet. Other parts of this chip are a little stranger. There is a bizarre register that isn’t documented anywhere, a Bus Unit that handles the access between various devices and peripherals, and a motion picture decompressor.
The reverse engineering process begins by de-encapsulating the CPU, GPU, sound processing unit, and CD-ROM controller, taking very high magnification photos of the dies, and slowly mapping out the semiconductors and metals to figure out what cells do what function, how they’re connected, and what the big picture is. It’s a painstaking process that requires combing through gigabytes of die shots and apparently highlight gates, wires, and busses with MS Paint.
The end result of all this squinting at a monitor is turning tracings of chips into logic elements with Logisim. From there, the function of the CPU can be understood, studied, and yes, eventually emulated down to the gate level. It’s an astonishing undertaking, really.
If this sort of thing sounds familiar, you’re right: the same team behind PSXDEV is also responsible for a similar effort focused on the Nintendo Entertainment System. There, the CPU inside the NES – the Ricoh 2A03 – was torn down, revealing the 6502 core, APU, DMA, and all the extra bits that made this a custom chip.
Thanks [Rasz] for the tip.
Filed under: playstation hacks, teardown
You might notice that many of my writings start with “Back in the day”. Not wanting to disappoint I will say that back in the day we used to use wire wrap technology when we needed a somewhat solid, somewhat reliably assembly. Given a readable schematic a good tech could return a working or near-working unit in a day or two depending on the completeness and accuracy of the schematic.
Properly done a wire wrap assembly is capable of fairly high speed and acceptable noise when the alternative option of creating a custom PCB would take too long or not allow enough experimentation. Wire wrap is also used in several types of production, from telco to NASA, but I am all about the engineer’s point of view on this.
My first wire wrap tool and wire wrap wire came from Radio Shack in the mid 1970’s. I still have the wire, because frankly its kind of cheap wire and I use it when it’s the only thing I can reach quickly when I need to make a jumper on a PCB. The tool is still around also, given the fact that I can’t find it at the moment the one shown here is my new wire wrap tool which is good for low quantity wrapping, unwrapping and stripping.
The skinny little wrap tool is okay for hobbyist as the wraps are fine with a little practice. But I do recommend investing in high-quality wire. A common wire available is Kynar® coated, a fluorinated vinyl that performs well as an insulator.
Before I go too much further, here’s the video walkthrough of wire wrap, its uses, and several demonstration. But make sure you also join me after the break where I cover the rest of the information you need to start on the road to wire wrap master.
Another important You will also hear me harp on good power and ground layout; “stubs or lengths of power supply wire that terminate in dead ends should be kept to a minimum and the power and ground wires are routed in close proximity to each other. Inductively coupling the supply and return together reduces impedance, hence noise. Obviously there is a lot more to it than that but that’s for another video.
A good wrap has 3-4 turns of the exposed wire on the square post and a turn of insulated wire which improves resistance to vibration and vibration based failure. The drawing here is from the NASA standards part of their website showing an acceptable wrap.
Wire wrap sockets are still available and I keep wire wrap SIP terminal strips as a custom socket footprint can be created as needed.
For more complex wire wrap components such as connectors you might have to find other sources such as electronic junk-yards. Hackaday’s [Brian Benchoff] was able to get a 64 pin “Hershey Bar” wire wrap socket from Apex Electronics in Sun Valley CA with an assist from [Todd Black].Wrap-ID Labels for Wire Wrap
Little slip on tags are available to help keep track of “reversed” pin numbering as seen from the bottom of the board.
Wrapping a wire on a post is accomplished by first stripping back the insulation on the wire wrap wire to 1″. The bare wire is then inserted into the hole on the wire wrap tool end (that is not in the center), and then the wire is pushed in until it is stopped by the tool. Next the tool and wire is placed over the specific square post being sure that the post goes into the hole in the center of the tool. For a manual router the tool is rotated with slight downward force to keep the wire wrap tight until the wire is completely wrapped, between 5-6 turns.
With the hand operated or power tool the same procedure is performed with inserting wire into the tool, then placing tool and wire onto the post, and finally the tool wraps the number of turns it is set up for.
There are different techniques for organizing the wires on a wire wrap board; sometimes the wires are routed together down channels and sometimes the individual wires connect straight across the board in as little length as possible. Both techniques have pros and cons as crosstalk and impedance are affected by wire placement.
Discrete components can be soldered to headers that then insert into standard wire wrap sockets as shown above with the 3.3K resistors.
And finally a technician named [Jeff] in the old MOS/Commodore R&D lab showed me how his boards never seemed to have much slack in them. He would take one of the skinny wire wrap tools and get on a socket pin/tail, then rotate the pin itself taking up the slack. While this looks better what he didn’t really address was the fact he was making a more pronounced inductor at the end of some wires. The answer to this technique as well as the channel routing technique (the techs would actually lace up the little bundles some times) was that my boards were to be “jungle routed”, I.E. more or less straight connections between pins, and slack was to be dealt with by adding some convolutions in the wire between the two pins by looping over other pins, similar to what you see on a high speed PCB where a trace will take a few extra turns to control the length/propagation time.
I should tell you that [Jeff] threw away my coffee cup one day because of what I had growing in it. From that day until I left Commodore I would make at least one trip a day to the R&D lab to throw his coffee cup away.
[Wire wrap diagram is from the nasa.gov website on Discrete Wiring]
Filed under: Featured
Summoning 4chans, 9gags, Reddits and other denizens of easily-digested content, Liberty Games stripped apart a dilapidated “Baby Doll” pinball arcade machine and turned it into this meme-spouting monstrosity. A complete redo of the vinyl and graphics to sport dozens of familiar internet tropes was first, then they had Shapeways create internal scenery and finally some electronics were added to spice things up.
We have seen PINMAME-based digital machines but this took a different path. Pinball machines this old pre-date common transistors so they rely on electro-mechanicals for everything. This made hacking the machine challenging so the team intercepted most of the signals and tied them into a Raspberry Pi with a Pi-face interface board. A videoscreen was added to the scoreboard, triggering all manner of memey videos and sounds according to actions performed and unlocked on the screen.
If you yearn for expired pranks of years gone by and are bad at pinball, you are in luck. Losing the game gets you Rickrolled – over and over again. On the plus side, Nyan Cat rockets away to bonuses and even the Admiral himself warns you of impending danger.
We resisted the urge to write this article as a chain of one meme to the next, you will get plenty of that from the well-documented project conversion and the following video. Someone in the comments will probably make a list of all memes.http://www.libertygames.co.uk/blog/wp-content/uploads/2014/09/internet-meme-pinball.mp4
Filed under: classic hacks, Raspberry Pi
When [Ch00f] was getting jeans rung up at Nordstroms, he noticed how fast thermal receipt printers can put an image on a piece of paper. This observation isn’t unique to the circles [Ch00f] frequents – there are a few small receipt paper printers out there that connect to the Internet, iPhones, and a whole bunch of other Kickstarter-friendly keyword devices.
Nevertheless, a device that can make a hard copy of an image quickly and cheaply isn’t something you just stop thinking about. After rolling the concept around in his head for a few years, [Ch00f] finally came up with the perfect build – a camera.
The hardware for the build is based around an STM32F4 Discovery board. It’s a bit overpowered for this sort of application, and this is one of [Ch00f]’s first adventures in ARM-land. The rest of the hardware consists of a thermal receipt printer and a JPEG camera, the latter of which replaced a cellphone CMOS camera module that was lost in a move.
A custom camera requires a custom enclosure, and for this [Ch00f] made something remarkable. The entire enclosure is CNC milled out of a beautiful piece of figured walnut. The end result looks far too good for a prototype, but it does polish up nicely with a bit of linseed oil.
Now [Ch00f] has an instant camera that takes the idea of a Polaroid and turns it into something that produces a print for tenths of a cent. There’s a time-lapse function – just a zip tie on the shutter button – filters with the help of highlighters, and the ability to record movies in flipbook format.
It’s a great project, and also something that will make for a great crowdfunding campaign. [Ch00f] has already started work on this. He already has a sleek, modern-looking website that requires far too much scrolling than should be necessary – the first step to a winning Kickstarter. [Ch00f] also learned a lot about ARMs, DMA, dithering, gamma correction, and the JPEG format, but that’s not going to get anyone to open up their wallet. You know what will? A slick video. You’ll find that below.
Filed under: ARM, digital cameras hacks
Several years ago [dan] saw some plastic frame bikes designed by MIT students. Ever since he saw those bikes he thought it would be cool to make an edge-lit plastic framed bike.
The frame is made from 1/8″ and 3/8″ thick polycarbonate sheet. The parts were designed with tongue and grooves so they fit together nicely. The joints were glued to hold everything together. Holes were drilled in the edge of the plastic large enough to fit an LED. Once the LED was inserted in the hole, it was wired up and secured with hot glue. There are about 200 LEDs on the bike, powered by a constant current LED driver circuit that [dan] designed specifically for this project.
The build process was certainly not flawless. For example, the plastic holding the bottom bracket (where the crank and pedals attach) broke. This can be avoided by increasing the amount of material in that area prior to cutting out the pieces. [dan] was able to fiberglass his broken parts back together.
[dan] admits that the bike is heavy and a little wobbly, but is definitely ride-able. He did us a favor and made all his CAD files available to anyone that wants to make one themselves. If polycarbonate is too expensive for your blood, check out this bike make from cardboard.
Filed under: transportation hacks
[psgarcha]’s modem/router comes straight from his internet provider, is on 24/7, and is built with the cheapest components imaginable. Eventually, this will be a problem and for [psgarcha], this problem manifested itself sooner than expected. Fortunately, there was a soldering iron handy.
The problems began with a boot loop – starting the router up, watching the blinking LEDs, and watching these lights follow the same pattern forever. Initially thinking this would be a problem with the firmware, [psgarcha] did the only thing he could do – take it apart. Inside, he found some bulging capacitors. Unsheathing his iron and replacing the obviously faulty components, [psgarcha] plugged the router in and had everything work. Great. Until those caps failed again a few months later.
There was obviously something wrong with the circuit, or wrong with the environment. Figuring it was hot out anyway, [psgarcha] replaced those caps again and added a fan and a small heatsink to the largest chip on the board. This should solve any overheating problems, but the real testing must be done in summer (or putting the router in a well-insulated enclosure). It’s an easy fix, a good reminder of exactly how often caps fail, and a great example of reducing the electronic cruft building up in landfills.
Filed under: repair hacks
Two Cornell students have designed their own multi-factor authentication system. This system uses a PIN combined with a form of voice recognition to authenticate a user. Their system is not as simple as speaking a passphrase, though. Instead, you have to sing the correct tones into the lock.
The system runs on an ATMEL MEGA1284P. The chip is not sophisticated enough to be able to easily identify actual human speech. The team decided to focus their effort on detecting pitch instead. The result is a lock that requires you to sing the perfect sequence of pitches. We would be worried about an attacker eavesdropping and attempting to sing the key themselves, but the team has a few mechanisms in place to protect against this attack. First, the system also requires a valid PIN. An attacker can’t deduce your PIN simply by listening from around the corner. Second, the system also maintains the user’s specific voice signature.
The project page delves much more deeply into the mathematical theory behind how the system works. It’s worth a read if you are a math or audio geek. Check out the video below for a demonstration.
Filed under: security hacks
There’s just something about the holidays and man’s best friend that brings out the best in people. [Tara Anderson], Director of CJP Product Management at 3D Systems, fostered a husky mix named Derby. Derby was born with a congenital defect: his forelegs were underdeveloped with no paws. This precluded the poor fellow from running around and doing all of the things dogs love to do. [Tara] had fitted him with a wheel cart, but she still felt that Derby deserved more mobility and freedom. Deciding that 3D-printed prosthetics was the answer, she turned to her colleagues and collaborated with Derrick Campana, a certified Animal Orthotist, to create a new set of forelegs for Derby.
The design is different from typical leg prosthetics; Tara felt that the typical “running man” design would not work for a dog, since they’d just sink right into the ground. Instead, the “loop” design was used, allowing for more playful canine antics. They were constructed using MultiJet Printing on the 3DS’ ProJet 5500X. MultiJet Printing enabled the prosthetics to be printed with firm and soft parts, both needed for comfort and durability.
The first set they designed is lower, to help ease the dog into using the prosthetics and strengthening his muscles. As he grows more accustomed to his newfound mobility, newer ones will be printed that will gradually increase in height. Derby has taken a shine to his new legs, happily gallivanting around and in some cases outrunning his new owners!
This is a very neat variation on prosthetics; we are impressed with the novel design and efficacy. We would love to see this MultiJet concept explored in the Maker community with open-source platforms and materials, as well as more unconventional designs made possible by 3D-printing. We never get tired of seeing the many ways people have already created amazing prosthetics for men, women, and children. No matter your personal opinion on 3D Systems, you can’t deny that Derby is having a blast with his awesome gams.
Filed under: 3d Printer hacks
What do you get when you have a computer-controlled laser pointer and a big sheet of glow in the dark material? Something very cool, apparently. [Riley] put together a great build that goes far beyond a simple laser diode and servo build. He’s using stepper motors and a proper motion control software for this one.
The theory behind the device is simple – point a laser at some glow in the dark surface – but [Riley] is doing this project right. Instead of jittery servos, the X and Y axes of the laser pointer are stepper motors. These are controlled by an Arduino Due and TinyG motion control software. This isn’t [Riley]’s first rodeo with TinyG; we saw him at Maker Faire NYC with a pendulum demonstration that was absolutely phenomenal.
Right now, [Riley] is taking SVG images, converting them to Gcode, and putting them up on some glow in the dark vinyl. Since the Hackaday Skull ‘n Wrenches is available in SVG format, that was an easy call to make on what to display in weird phosphorescent green. You can see a video of that along with a few others below.
Filed under: laser hacks
Lumographic images are those patterns you see at the bottom of swimming pools. When water works as a lens, the light patterns of bright and dark are random and wandering based on the waves above. [Matthew] figured out a way to create fixed images from lens shape alone. The images only morph into view clearly when light shines at the proper angle. At near angles an eerie fun-house mirror effect appears, but too far off and it scatters unrecognisably.
The exact method for designing the optics is not explained, though we are sure someone in our readership could figure it out. The artist claims it to be a hundred year old million-variable math problem. The lenses are often quite thick and do not resemble much of anything. The effect however, is sharp, clear and detailed.
At first he suspected he needed astronomically-expensive military-grade 50 nanometer (0.000002″) precision machining for the lenses, but some friends in the autobody industry gave him a few tips to squeeze good enough accuracy from more affordable industrial machines. The technique also allows for images to appear from mirrors and internal reflections. It is probably not something you can 3D print or machine yourself, but it would be interesting to see someone try.
[Matthew]’s work is on display in the “Composite” gallery at the National Museum of Math in New York (MoMath). See the video after the break for a peak at the machinery he uses to manipulate the lenses to enhance the visuals in the exhibit.
Filed under: misc hacks
Whether you call them individually controllable RGB LEDs, WS2812, or NeoPixels, there’s no denying they are extremely popular and a staple of every glowey and blinkey project. Fresh off the reel, they’re nearly useless – you need a controller, and that has led to many people coming up with many different solutions to the same problem. Here’s another solution, notable because it’s the most minimal WS2812 driver we’ve ever seen.
The critical component in this build is NXP’s LPC810, an ARM Cortex M0+ in an 8-pin DIP package. Yes, it’s the only ARM in a DIP-8, but still able to run at 30MHz, and hold a 4kB program.
JeeLabs is using the SPI bus on the LPC810 to clock out data at the rate required by the LEDs. The only hardware required is a small LED to drop the voltage from 5V to 3.3V and a decoupling capacitor. Yes, you could easily get away with this as a one-component build.
The build consists of a ring of sixty WS2812b RGB LEDs, and the chip dutifully clocking out bits at the correct rate. It’s the perfect start to an LED clock project, an Iron Man arc reactor (are we still doing those?), or just random blinkey LEDs stuffed into a wearable.
Thanks [Martyn] for sending this one in.
Filed under: ARM, led hacks
Take it from someone who has played at the guitar for over 20 years: reading sheet music can be a big stumbling block to musical enjoyment. Playing by ear is somewhat unreliable, tablature only works well if you’re already familiar with the tune and tempo, and pulling melody from chord charts is like weaving fiction from the dictionary. A lot can be said for knowing basic chord formations, but it can be difficult get your fingers to mimic what you see on the page, the screen, or someone else’s fretboard. Enter Ukule-LED, a learning tool and all-around cool project by [Raghav and Jeff] at Cornell.
Ukule-LED uses 16 NeoPixels across the first four positions of the fretboard to teach chord positions. All 16 NeoPixels are connected in series to a single pin on an ATMega1284P, which sits on a board mounted to the bottom of the uke along with power and serial. [Raghav and Jeff] set the NeoPixels below the surface so as not to interrupt playability. The uke can operate in either of two modes, ‘play’, and ‘practice’. In ‘play’ mode, the user feeds it a text file representing a song’s chords, tempo, and time signature. The LEDs show the chord changes in real-time, like a karaoke teleprompter for fingers. In ‘practice’ mode, the user enters a chord through the CLI, and the lights hold steady until they get a new assignment. Knowing which fingers to use where is up to the user.
To add another layer of learning, major chords alight in green, minor chords in red, and 7th chords in blue. These are the currently supported chord types, but the project was built with open, highly extendable Python sorcery available for download and subsequent tinkering. Go on tour after the break.
Filed under: Microcontrollers, musical hacks
The ESP8266 Internet of Things module is the latest and greatest thing to come out of China. It’s ideal for turning plastic Minecraft blocks into Minecraft servers, making your toilet tweet, or for some bizarre home automation scheme. This WiFi module is not, however, certified by the FCC. The chipset, on the other hand, is.
Having a single module that’s able to run code, act as a UART to WiFi transceiver, peek and poke a few GPIOs, all priced at about $4 is a game changer, and all your favorite silicon companies are freaking out wondering how they’re going to beat the ESP8266. Now the chipset is FCC certified, the first step to turning these modules into products.
This announcement does come with a few caveats: the chipset is certified, not the module. Each version of the module must be certified by itself, and there are versions that will never be certified by the FCC. Right now, we’re looking at the ESP8266-06, -07, -08, and -12 modules – the ones with a metal shield – as being the only ones that could potentially pass an FCC cert. Yes, those modules already have an FCC logo on them, but you’re looking at something sold for under $5 in China, here.
Anyone wanting to build a product with the ESP will, of course, also need to certify it with the FCC. This announcement hasn’t broken down any walls, but it has cracked a window.
Filed under: hardware
We’ve held our third drawing for the Trinket Everyday Carry Contest. Once again we’ve used a Pro Trinket to pick the random winner. This week’s winner is [Scissorfeind] with his project Stylin’ safety jacket
In true hack style, [Scissorfeind] went into this project with two goals: A jacket that will be visible at night, and keep him “looking f*cking sick”. The jacket itself is a faux leather affair from a thrift store. [Scissorfeind] added some studs for bling, and he’s working on adding a ton of electronics for light.
The Pro Trinket will be driving a series of LED matrices, which [Scissorfeind] is working on turning into POV displays. The matrices come from an LED clock which [Scissorfeind] saved from the landfill. In fact, most of the parts in the jacket are upcycled from e-waste. The jacket is just starting to come together. We can’t wait to see the final results!
We hope that [Scissorfeind] enjoys his Bus Pirate V3.6 from The Hackaday Store. The Bus Pirate was designed by former Hackaday writer [Ian Lesnet] as a Swiss Army knife of electronic communications. If you’re trying to connect to a circuit with SPI, I²C, JTAG, or UART, the Bus Pirate has you covered. It can do plenty more though – from reading analog data to programming components. Check out [Brian Benchoff’s] full review on the Bus Pirate V3.6 product page!
If the pseudo random number gods didn’t smile on you this week, don’t worry, there are still two more chances to win a random drawing! Our next drawing will be on 12/23/2014 at 9pm EST. The prize will once again be a Cordwood Puzzle! To be eligible you need to submit your project as an official entry and publish at least one project log during the week.
The main contest entry window closes on January 2, 2015 – but don’t wait for the last minute! Hit the contest page and build some awesome wearable or pocketable electronics!
Filed under: contests, Featured
Keurig, the manufacturer of a single-serve coffee brewing system, has a very wide following amongst coffee drinkers. Their K-cup (pre-packaged coffee grounds with a coffee filter, all in a plastic container) is an interesting concept and makes brewing a single cup of coffee much more efficient over making a whole pot. Their newer line of coffee makers, the Keurig 2.0, has some interesting (and annoying) security features though, which [Kate Gray] has found an interesting and simple way around.
The DRM security in these coffee makers is intended to keep third-party “cups” from being used in the Keurig. It can recognize an authentic Keurig cup, and can stop the operation of the coffee pot if a knockoff is placed in the machine. We can only assume that this is because Keurig makes a heap of cash by selling its canisters of coffee. The simple solution? Removing one wire from a wiring harness inside of the case.
There are other ways around the security on these devices, but when [Kate Gray] actually investigated, she found the security decidedly lacking. With something this simple, one can only speculate how much Keurig has really invested in making sure users don’t use third-party cups of coffee in their machines, but it also brings up the classic question of who really owns hardware if we can’t use it in the way we want, rather than the way the manufacturer wants.
You can read more about the project on its Reddit page. Thanks to [MyOwnDemon] for the tip!
Filed under: home hacks
If choosing a rechargeable battery for your project intimidates you, [Afroman] has prepared a primer video that should put you at ease. In this tutorial for battery basics he not only walks you through a choice of 5 rechargeable chemistries and their respective tradeoffs, but gives a procedure that will allow you to navigate through the specs of real-world batteries for sale – something that can be the most intimidating part of the process.
You cannot learn everything about batteries in 9 minutes, but watching this should get you from zero to the important 80% of the way there. Even if your project does not give you the specs you need to begin buying, [Afroman] tells you what to measure and how to shop for it. In particular, the information he gives is framed in the context you care about, hopefully ensuring you are not waylaid by all the details that were safe to ignore. If this is not enough, [Afroman]’s prequel video on battery terminology has more detail.
Much like your high school English teacher told you, you need to know the rules before you can choose to break them. Many of battery absolute Dos or Don’ts are written for the manufacturer, who provides for the consumer, not the hacker. Hackaday has published hundreds of battery articles over the years; search our archives when you are ready for more.
Filed under: how-to, parts
Personal UAV’s are becoming ubiquitous these days, but there is still much room for improvement. Researchers at [Modlab] understand this, and they’ve come up with a very unique method of controlling pitch, yaw, and roll for a coaxial ‘copter using only the two drive motors.
In order to control all of these variables with only two motors, you generally need a mechanism that adjusts the pitch of the propeller blades. Usually this is done by mounting a couple of tiny servos to the ‘copter. The servos are hooked up to the propellers with mechanical linkages so the pitch of the propellers can be adjusted on the fly. This works fine but it’s costly, complicated, and adds weight to the vehicle.
[Modlab’s] system does away with the linkages and extra servos. They are able to control the pitch of their propellers using just the two drive motors. The propellers are connected to the motors using a custom 3D printed rotor hub. This hub is specifically designed to couple blade lead-and-lag oscillations to a change in blade pitch. Rather than drive the motors with a constant amount of torque, [Modlab] adds a sinusoidal component in phase with the current speed of the motor. This allows the system to adjust the pitch of the blades multiple times per rotation, even at these high speeds.
Be sure to watch the demonstration video below.
Filed under: drone hacks
They said it couldn’t be done, and perhaps it shouldn’t have been attempted. Shouldas and couldas aside, the oil crisis of the 1970s paved the legislative way for an 800-mile pipeline across the Alaskan frontier, and so the project began. The 48-inch diameter pipe sections would be milled in Japan and shipped to Alaska. Sounds simple enough. But of course, it wasn’t, since the black gold was under Prudhoe Bay in Alaska’s North Slope, far away from her balmy southern climes.
The Trans-Alaska Pipeline System was constructed in three sections: from Valdez to Fairbanks, Fairbanks to a point in the Brooks Pass, and south from Prudhoe Bay to the mountain handoff. Getting pipe to the Valdez and Fairbanks is no big deal, but there is no rail, no highway, and no standard maritime passage to Prudhoe Bay. How on earth would they get 157 miles worth of 58-foot sections of pipe weighing over 8 tons each up to the bubblin’ crude?
Barges! Ridiculously huge, specifically-built barges with 35-foot stanchions to hold pipe sections stacked on decks as large as football fields. Four barges were built close to the steel mills, two in Japan and two in Hong Kong. Several other barges were constructed stateside, departing regularly from Tacoma to meet the demanding timeline of the project. The barges headed for Prudhoe Bay from Asia would be towed 3300 miles by a pair of heroic tugboats to rendezvous with the other barges at Nome.
About 150 miles from Prudhoe Bay, the tugs encountered the arctic ice floe as expected. What they didn’t expect was no sign of an open channel. Time was of the essence here: if they didn’t make it to Prudhoe and back within about a month, they’d be mired in ice all winter long. Each tug was towing two barges in tandem. Since no channel ever opened, they decided to anchor each tug’s rear barge, take the lead barges through the ice all nice and easy, and come back for the rest. Ninety miles of ice cakes and cursing later, they reached the open waters of the Arctic Ocean and floored it for Prudhoe Bay. Pretty slick stuff, eh?
Retrotechtacular is a weekly column featuring hacks, technology, and kitsch from ages of yore. Help keep it fresh by sending in your ideas for future installments.
Filed under: Hackaday Columns, Retrotechtacular