Formlabs makes a pretty dang good SLA printer by all accounts. Though a bit premium in the pricing when compared to the more humble impact of FDM printers on the wallet, there’s a bit more to an SLA printer. The reasoning becomes a bit more obvious when reading through this two part series on the design and testing of the Form 2.
It was interesting to see what tests they thought were necessary to ensure the reliable operation of the machine. For example the beam profile of every single laser that goes into a printer is tested to have the correctly shaped spot. We also thought the Talcum powder test was pretty crazy. They left a printer inside a sandblast cabinet and blasted it with Talcum powder to see if dust ingress could cause the printer to fail; it didn’t.
The prototyping section was a good read. Formlabs was praised early on for the professional appearance of their printers. It was interesting to see how they went from a sort of hacky looking monstrosity to the final look. They started by giving each engineer a Form 1 and telling them to modify it in whatever way they thought would produce a better layer separation mechanism. Once they settled on one they liked they figured out how much space they’d need to hold all the new mechanics and electronics. After that it was up to the industrial designer to come up with a look that worked.
They’re promising a third part of the series covering how the feedback from beta testing was directed back into the engineering process. All in all the Form 2 ended up being quite a good printer and the reviews have been positive. The resin from Formlab is a little expensive, but unlike others they still allow users to put the printer in open mode and use other resin if they’d like. It was cool to see their engineering process.
Filed under: 3d Printer hacks
A recurring idea in hackspaces worldwide seems to be that of the vending machine for parts. Need An Arduino, an ESP8266, or a motor controller? No problem, just buy one from the machine!
Most such machines are surplus from the food and drink vending industry, so it’s not unusual to be able to buy an Arduino from a machine emblazoned with the logo of a popular chocolate bar. These machines can, however, be expensive to buy second-hand, and will normally require some work to bring into operation.
A vending machine is not inherently a complex machine nor is it difficult to build when you have the resources of a hackspace behind you. [Mike Machado] is doing just that, building the Vendotron, a carousel vending machine constructed from laser cut plywood and MDF. The whole thing is controlled by an Arduino, with the carousel belt-driven from a stepper motor.
It’s not doing anything commercial vending machines haven’t been doing for years, except maybe having a software interface that allows phone and Bitcoin payments. Where this project scores though is in showing that a vending machine need not be expensive or difficult to build, and broadening access to them for any hackspace that wants one.
We’ve had a few vending machines here before, like this feature on the prototyping process for commercial machines, or even this one that Tweets. Sadly few have a secret button to deliver a free soda though.The HackadayPrize2016 is Sponsored by:
Filed under: hardware
A fun thread over at the EEVblog forum starts off with [TerraHertz]’s triangle-peg, square-hole capacitor repair job and goes entertainingly down-hill from there.
Everything from horrifying eBay purchases to work (horror) stories can be found in this thread. But you can learn something too. Did you know the correct way to fix a mercury switch stored in the incorrect orientation is to whack it against a table really hard?
We enjoyed the cigarette box shroud used to fix a graphics card with a defective fan. We’re still not sure about the person who managed to Dremel bits off a graphics card and end up with a working PCI-e card. That one may be a troll.
Regardless, it’s a lot of fun, spanning the hilariously bad and the seriously impressive. We would not be surprised if some of these people met the devil at the crossroads for some soldering skill. Do any of you have an interesting or ugly repair to share? We’d love to see it.
Filed under: misc hacks
Today at the Open Hardware Summit in Portland, Alicia Gibb and Michael Weinberg of the Open Source Hardware Association (OSHWA) launched the Open Source Hardware Certification program. It’s live, and you can certify your own hardware as Open Hardware right now.What Is Open Source Hardware?
Open Source Hardware can’t be defined without first discussing open source software. At its very core, open source software is just a copyright hack, enabled by a worldwide universal computer network. The rise of open source software is tied to the increasing ease of distributing said software, either through BBSes, Usenet, and the web. Likewise, Open Source Hardware is tied to the ease of distributing, modifying, and building hardware.
In the 1980s, there were no services that could deliver a custom circuit board to anywhere on the planet for a dollar per square inch. When open software began, CNC machines were expensive tools, now you can build a very good machine for just a week’s wages. We are currently living at the dawn of Open Source Hardware, enabled by the creation of Open Source design tools that have themselves been used to create physical tools. Inexpensive 3D printers, open source oscilloscopes, circuit board plotters, and the entire hackerspace movement are as revolutionary as the Internet. These devices and the Internet are the foundations for Open Hardware and software, respectively. The objections to why hardware is incompatible with Open Source no longer apply and small-scale manufacturing techniques are only going to get better.
Open source is a moral imperative in the truest Kantian sense of the word. It is a good unto itself. Of course, this means open source is also mind-numbingly prescriptivist. Holy scrolls have defined dozens of different open source licenses. The relevant license for Open Source Hardware has already been laid out to define the freedoms and responsibilities of all Open Source Hardware creators. Open Source Hardware is a tangible thing, from a laptop to a lampshade, whose design is available so anyone can make, modify, distribute, and sell that thing. Native documentation is required, and software required to run this thing must be based on an OSI-approved license.
The definition of Open Source Hardware has been around for a few years now, and since then the community has flourished, there’s a great gear logo, and you can buy real, functional hardware that bills itself as Open Source Hardware. It’s become a selling point, and this has become a problem.
Many hardware creators don’t adhere to the definition of Open Source Hardware. In some cases, the design files simply aren’t available. If they are, they could be unmodifiable. The software used to create these design files could cost thousands of dollars per seat. This is the problem the movement faces — Open Source Hardware must have a certification program. Unlike open source software, where the source is almost proof enough that a piece of software complies with an open source license, hardware does not have such obvious assurances.Software Is Closed By Default, Hardware Is Open And The Licenses Are Harder
All software is closed by default. Anything written is covered by copyright, and the developers of open source software choose to license their works under an open source license. Open source software, then, is a copyright hack, enabled because all software is closed by default.
Hardware, on the other hand, is open by default. If you build a device to automatically inject epinephrine intramuscularly, you must go out of your way to patent your device. Only a patent will give you the ability to license your work, and before that patent is published anyone can make their own epinephrine pen. If you build something with an FPGA, the code that programs the FPGA is covered by copyright, but an arbitrary circuit that uses that FPGA isn’t. Any generic piece of Open Source Hardware could be covered under patents, trademarks, and a dozen licenses. Therefore, an Open Source Hardware license is impractical. This is why OSHWA is not releasing an Open Source Hardware license, and instead creating an Open Source Hardware certification program. No Open Source Hardware license could cover every edge case, and a certification is ultimately the only solution.The Open Source Hardware Certification Program
At last year’s Open Hardware Summit, OSHWA formally announced the creation of the Open Hardware Certification program. Now, this program is live, and the certification database will growing very, very quickly. At its heart, the Open Source Hardware Certification program is pretty simple — create hardware that complies with the community definition of Open Source Hardware.
The theoretical basis for the need of an Open Source Hardware license is the fact that anyone is able to manufacture hardware. Of course, there are limits to technology and no one has a 14nm silicon fab line in their garage. This is a problem for any piece of Open Source Hardware, and the technical capability for anyone to recreate integrated circuits and other high technologies is the sole source of the traditional objections to any open hardware license. Garage-based fabrication is always improving, though, but closed hardware in the form of NDA’d chips will remain a problem for years to come.
The clearest example of the problem with closed-source chips is bunnie’s Novena laptop. This laptop is designed as both a hacker’s laptop and an artifact of Open Hardware. Although most of the chips used in the Novena are available without signing NDAs, open source, and blob-free 3D graphics acceleration was unavailable when the laptop launched. This non-open graphics problem will be fixed with open source drivers, but it does illustrate the problem of Open Source Hardware. Even though chips might be available, there might be binary blobs required for full functionality. You can build an Open Hardware chip in VHDL, but it’s not really open if you have to use closed-source FPGA dev tools.
OSHWA’s solution to this problem is simply asking for hardware creators to act in good faith. The certification program won’t knock points off for using closed source binary blobs if that’s the only way of doing something. Open Source Hardware is just slightly more aware of the pace of technical progress, and what is closed today may be open tomorrow. Building a piece of Open Source Hardware isn’t an all or nothing proposal; just give your best effort to make it open, and technology or reverse engineers will probably make it more open in the future.
Of course, with any certification program, there must be some effort given to enforcement. If an Open Hardware project is certified under the program but does not meet the guidelines of the certification program, fines may be levied against the project creators. Again, good faith of the project creator is assumed, and a project found not in compliance with the certification program will be given 90 days to either fix the problem or remove the project from the certification program. After 90 days, there’s a 120-day period of public shaming, and after that small fines of $500 per month. The worst offender will get a fine of up to $10,000 per month, but that would require years of non-compliance, and it’s very doubtful any conflict with OSHWA will ever reach that stage. It should be noted these fines have a legal basis in the trademark of the OSHW certification logo, and if you don’t use the OSHW logo or certify your project, there’s nothing OSHWA can do.
The old Open Source Hardware ‘gear’ logo — unquestionably a better logo — will still remain in use, and no one is going will look down on you for using it. Using the trademarked OSHW logo, though, is the only way any certification program can be enforced.The Objections To Open Source Hardware
Of course, the Open Source Hardware Certification program has been more than two years in the making, and that’s time enough for a few people to start having very strong opinions about it. A few years ago, Saar Drimer of Boldport said he won’t be using the Open Source Hardware logo on his boards. This is despite the fact that he loves Open Source Hardware, has written open source PCB design software, and offers a 20% discount on open source contract work. His reason is simple: adding a logo brings baggage, and building Open Source Hardware is not mutually exclusive with putting a logo on a board. Dave Jones is a big supporter of Open Hardware, but he realizes the famous gear logo is becoming meaningless through abuse.
You need only look back on the last twenty or thirty years of the world of Open Source Software to get a sense of where Saar and Dave are coming from; Stallman does not believe in a moral imperative to Open Hardware, whereas most everyone in attendance of today’s Open Hardware Summit does. Gnome versus KDE is nothing compared to the religious war we potentially face between various Open Hardware philosophies. The Open Source Hardware community is relearning what the open source software community learned twenty years ago. We can only hope to learn from their missteps.
But Open Source Hardware has a much bigger obstacle to adoption than politicking and empire building. Open source software is a simple concept — you have a (copy) right to whatever software, music, words, or boat hull designs you create. You can, therefore, give others the right to use, study, share, and modify that work. Physical objects and artifacts do not have copyright, they have patents. Patent law in the United States is atrocious, and just because you were the first to create a useful invention doesn’t mean a patent would be invalidated. This is the greatest challenge to anything developed as Open Source Hardware. The only solution to this is prior art and patent inspectors that know where to look.This Will Take a While to Work Out
The Open Source Hardware Certification program is going to take a while to unravel. OSHWA doesn’t believe this certification program will be a repository used by patent inspectors looking for prior art. The legal basis for the certification is literally built upon every piece of intellectual property law. It is, perhaps, an answer to the most complex legal questions ever: what is property, what is intellectual property and can the concept of physical things be given away.
No one has an answer to these questions, or at least an answer that can be summed up in one-page FAQ. The Open Source Hardware Certification program is an attempt to answer these questions, and so far it’s the best attempt yet.
None of this matters unless the community gets behind it, and if another competing Open Source Hardware certification or license pops up, the community may very well migrate to that. Judging from the last thirty years of open source software license drama, we can only hope that the community figures this out the first time, and we hope this certification program is a rousing success.
Filed under: Featured, news, slider
[Nicomedia] (a team of two) built a payload for their drone with two distinct purposes: to allow it to drop things like rose petals and to fire off fireworks. Honestly, while it is a cool idea, we are a little worried that dropping things from a height might not be a good idea (although rose petals are probably OK) and lighting off fireworks from a drone didn’t seem like a good idea at all. If you want to reproduce this, you probably need to make sure either of these things are legal in your part of the planet.
In the video below, you can see the effect. A servo tied to the drone’s controller opens the box to release the payload. In this case, the team didn’t have a spare channel so they used a separate controller, but if you had a spare channel on the flight controller, that would probably be better.
The description of the fireworks part isn’t very detailed and there’s no pictures or videos. That’s probably just as well, since that’s probably not something you ought to do, anyway. The good news is that the typical drone can’t carry anything to heavy to drop on people or blow up.
Filed under: drone hacks
If you deploy a lot of Raspberry Pi computers, you might find it inconvenient to log into each one to perform different tasks. Orka, an open source project by [Karthik K], is a server that runs on a desktop PC (Windows, Linux, or Mac) and can control multiple Orka clients (that can run on a Pi, or a desktop PC). We understand that [Karthik K] is looking for Mac testers, by the way.
From the server, you can execute commands and create tasks. You can also receive notification when a client PC reaches a threshold (for example, over temperature or too much CPU or RAM usage). You can open a shell on a client and do other operations.
Filed under: Raspberry Pi
I’m guessing most of the members of the Hackaday community are what most people would consider early adopters. Sure, there’s variation among us, but compared to the general population we probably all qualify. I’ve spent many years being an early adopter. I owned a computer, a TiVO, a digital camera, a 3D printer, a drone, and many other gadgets before they became well known. I’ve avoided the self-balancing conveyance craze (I’ll stick with my motorcycle).
Of course, you know if you are an early adopter, you will overpay. New has a premium, after all. But there is another price: you often have the first, but not the optimum. My first digital camera took 3.5 inch floppies. My TiVO has an analog tuner.
I was reminded of this last week. A number of years ago, I built a 3D printer. A lot of printers back then didn’t have heated build plates, so printing ABS required rafts and ABS juice and frustration. I made sure to get a heated bed and, like most people in those days, I had a glass print surface covered in Kapton.
That works pretty well with ABS, but it isn’t perfect. Aqua Net hair spray makes it stick better, but large flat prints still take a little work. With a little practice, it isn’t bad. I eventually switched to an aluminum bed and didn’t have to level the head quite as often, but it didn’t really make things any better, just more repeatable.
The years pass and other gadgets beckon. I use the printer about like I use a drill press. I don’t use it every day, but when you need it it is handy. I have to admit, I’ve been getting partial to PLA since it doesn’t warp. But PLA in the hot Houston sun isn’t always a good mix, so I still print a fair amount of ABS.
The other day I noticed a product called BuildTak. I also heard some people are printing on PEI sheets. I decided to try the BuildTak. Wow! What a difference.
I don’t want to turn this into a review on BuildTak–you can find those all over the Internet. I can’t compare it to PEI or any of the other newer solutions. I will say this: at first I didn’t adjust my first layer parameters–I usually print a little low and over-extruded to smoosh against the Kapton. You have to accept a little bit of a smashed base when you do this, but it helps with warping.
With the BuildTak, the print came out fine, but it was very difficult to remove from the print bed. A little reading (yeah, I don’t read directions so well) showed that the bed is tacky enough that you should not squash the plastic down. For the first time ever, I printed with the first layer high enough up to look like all the other layers and with no over-extrusion. The print popped right off and was perfectly flat.
I was embarrassed to find this isn’t such a new product. It was just new to me — an early adopter. The sheets aren’t cheap, but if you take care of them they appear to last, making this a cheap, easy upgrade. You still need a heated bed for ABS, by the way, so it isn’t a cheap upgrade for a non-heated printer.
But that’s not really my point. Gadgets get better and better, in general. Early adoption is fun, but don’t forget to track the state of the art to see where you can or should make improvements.
By coincidence, we recently talked about a printer that has a build plate that looks like rebranded BuildTak (but I don’t know if it is or just some similar material). Just to give PEI a fair shake, you can see a video about that material below.
Photo credit: [Chris Cecil] Creative Commons 2.0
Filed under: 3d Printer hacks, Featured, rants
If you’ve played around with “white” LEDs, you already know that there’s no such thing. There’s warm white and cool white and any numbers of whites in-between. And when white LEDs were new, the bluer “cool white” variety were significantly more prevalent.
Enough US states have swapped out their old street lights with LEDs that it may be having a measurable effect on people and on the animals around us. This is the claim in a recent position paper by the American Medical Association’s Council on Science and Public Health. (Report as PDF.)
Science strongly suggests that heavy doses of light can keep people from falling asleep, and that brighter LED streetlamps may be making the problem worse. The AMA report goes a step further, and pins extra blame on the color of the light. Blue light apparently suppresses the production of melatonin which helps you sleep at night. And it’s not just humans whose circadian rhythms are getting messed up — the effects are seen throughout the animal kingdom.
Blue light additionally diffracts funny in your eyeball — we’re sure you’ve noticed the strange appearance of blue LEDs and UV lasers. Add together tired drivers and glare-inducing streetlights, and you’ve got a recipe for disaster, even without taking into account those birds who keep peeping while they should be sleeping.
The benefits of LED lighting are huge, however. From an energy-efficiency standpoint, there’s no comparison. But it may be the case that initial adoption in streetlights ended up being too bright and too blue.
[via The Washington Post]
Filed under: led hacks, news
In the 1950s and 1960s, the prospects for a future powered by nuclear energy were bright. There had been accidents at nuclear reactors, but they had not penetrated the public consciousness, or had conveniently happened far away. This was the age of “Too cheap to meter“, and The Jetsons, in which a future driven by technologies as yet undreamed of would free mankind from its problems. Names like Three Mile Island, Chernobyl, and Fukushima were unheard of, and it seemed that nuclear reactors would become the miracle power source for the second half of the twentieth century and beyond.
The first generation of nuclear power stations were thus accompanied by extremely optimistic public relations and news coverage. At the opening of the world’s first industrial-scale nuclear power station at Calder Hall, UK in 1956, the [Queen] gave a speech in which she praised it as for the common good of the community, and on the other side of the Atlantic the American nuclear industry commissioned slick public relations films to promote their work. Such a film is the subject of this piece, and though unlike the British they could not muster a monarch, had they but known it at the time they did employ the services of a President.
The Big Rock Point nuclear power plant was completed in 1962 on the shores of Lake Michigan. Its owners, Consumers Power Company, were proud of their new facility, and commissioned a short film about it. The reactor had been supplied by General Electric, and fronting the film was General Electric’s established spokesman and host of their General Electric Theater TV show, the Hollywood actor and future President [Ronald Reagan].
The film below the break starts by explaining nuclear power as a new heat source powering a conventional steam-driven generator, and stresses the safety aspect of reactor control rods. We are then treated to a fascinating view of the assembly of an early-1960s nuclear reactor, starting with the arrival of the pressure vessel and showing the assemblies within it that held the fuel and control rods. Fuel rods are shown at their factory in California, and being loaded onto a truck to be shipped across the continent, seemingly without the massive security that would nowadays accompany such an undertaking. The rods are loaded and the reactor is started, as [Reagan] puts it: “The atom has been put to work, on schedule”.
The film captures well the optimism of the age, and it is obvious that there has been no need to consider the plant’s waste products or decommissioning costs when its $27m price is quoted. The plant was eventually shut down in 1997, and the site was decommissioned over the next decade. You can see pictures courtesy of attentive American rail enthusiasts, of the reactor vessel on a rail car as it heads for a nuclear waste containment site in South Carolina.
This hasn’t been our first expedition into early nuclear power publicity, we’ve previously shown you a General Electric film from 1952. If the inner workings of nuclear plants are your thing, we’d probably better also point you at a series of detailed cutaway diagrams of reactors from around the world.
Big Rock Point picture: Federal Government of the United States [Public domain], via Wikimedia Commons.Retrotechtacular is a column featuring hacks, technology, and kitsch from ages of yore. Help keep it fresh by sending in your ideas for future installments.
Filed under: Retrotechtacular
[Mike] had a bunch of disused fitness machines lying around. Being a skilled welder, he decided to take them apart and put them back together in the shape of a belt grinder.
In particular, [Mike] is reusing the height-adjustment guide rail of an old workout bench to build the adjustable frame that holds the sanding belt. A powerful DC motor including a flywheel was scavenged from one treadmill, the speed controller came from another. [Mike] won’t miss the workout bench: Once you’re welding a piece of steel tube dead-center on a flywheel, as happened for the grinder’s drive wheel, you may call yourself a man (or woman) of steel.
The finished frame received a nice paint job, a little switching cabinet, proper running wheels and, of course, a sanding belt. Despite all recycling efforts, about 80 bucks went into the project, which is still a good deal for a rock-solid, variable-speed belt grinder.
Apparently, disused fitness devices make an ideal framework to build your own tools: Strong metal frames, plentiful adjustment guides, and strong treadmill motors. Let us know how you put old steel to good use in the comments and enjoy [Mike’s] build documentation video below!
Filed under: tool hacks
[ITMAN496] and his local HAM radio group entered the Power Wheels Racing Series with great intentions, a feeling of unlimited power, and the universal spirit of procrastination all hackers share.
It wasn’t the first time his group had worked together on something a little different, such as a robot that can deploy an antenna by climbing poles. However, this one had a time limit and they ended up trying to fit it all in the week before the race.
They had a pretty good design. [ITMAN496] had modeled the entire frame in SketchUp and even did physics simulations to get the steering just right. However, the best laid plans of mice and men often don’t fully take into account just how hard it is to get the motor drivers they bought working.
In the end, what they really needed was time to test. The setscrews couldn’t hold the motor on the shaft, the electronics needed debugging, and one of the belts was too long. The design was solid, but without time to percussively maintain the last bugs out of the system, it just wasn’t going to run.
[ITMAN496] is taking this lesson properly; he’s already planning for next year’s run, but this time he’ll have time to test. We must commend him — the build under these time constraints was still impressive. Even more so that he took the time to document everything while it was happening, and to share the story of shortfall after the fact. We’re always on the hunt for documented fails (the best way to really learn something).Fail of the Week is a Hackaday column which celebrates failure as a learning tool. Help keep the fun rolling by writing about your own failures and sending us a link to the story -- or sending in links to fail write ups you find in your Internet travels.
Filed under: car hacks, Hackaday Columns
ALS robbed one of [C. Niggel]’s relative’s of the use of their upper body. This effectively imprisoned them in their house; ALS is bad stuff. Unfortunately too, the loss of upper body mobility meant that they couldn’t even use the computer to interact with people and the outside world. However, one day [C. Niggel] noted that the relative’s new electric wheelchair was foot controlled. Could this be adapted to a computer mouse?
He looked up commercial solutions and found them not only prohibitively expensive, but also fraught with proprietary drivers and all sorts of bad design nonsense. With all of the tools out there today there was no reason this couldn’t be quickly prototyped and sent to the relative in need.
He used a combination of conductive thread, neoprene, and velostat to build the pads themselves. The pads were balanced with some adjusting resistors in series. The signals are sent to an Adafruit Feather board which interprets them and converts it to a PS/2 standard.
The first version of the mouse used separate pads glued to a MDF board with contact cement. However this, along with some other initial design flaws, resulted in premature failure of the mouse. [C. Niggel] quickly returned to the lab and produced a new version with more robust construction and mailed it off. So far so good!The HackadayPrize2016 is Sponsored by:
Filed under: The Hackaday Prize
If you could only own one piece of test equipment, it should probably be an oscilloscope. Then again, modern scopes often have multiple functions, so maybe that’s not a fair assertion. A case in point is the Scopefun open hardware project. The device is a capable 2-channel scope, a logic analyzer and also a waveform and pattern generator. The control GUI can work with Windows, Linux, or the Mac (see the video, below).
The hardware uses a Xilinx Spartan-6 FPGA. A GUI uses a Cypress’s EZ-USB FX2LP chip to send configuration data to the FPGA. Both oscilloscope channels are protected for overvoltage up to +/- 50 V. The FPGA samples at 100 Mhz through a 10-bit dual analog-to-digital converter ( ADC ). The FPGA handles triggering and buffers the input before sending the data to the host computer via the USB chip. Each channel has a 10,000 sample buffer.
There are also two generator outputs with short circuit and overvoltage protection ( +/- 50 V ). Generator channels have 50 Ohm internal impedance and also operates via the GUI using the same USB chip. The FPGA generates signals at 50 Mhz using counters, algorithms, or simple waveform data and feeds a DAC.
A 16-bit digital interface can be set as inputs or outputs. The FPGA samples inputs at 100 MHz. The output voltage can be set, but inputs are 5 V tolerant.
According to the developer, you can build the scope from the information provided by using free sample chips from the various vendors, only paying for the small components and the cost of the PCB.
Filed under: tool hacks
Ever wonder why analog TV in North America is so weird from a technical standpoint? [standupmaths] did, so he did a little poking into the history of the universally hated NTSC standard for color television and the result is not only an explanation for how American TV standards came to be, but also a lesson in how engineers sometimes have to make inelegant design compromises.
Before we get into a huge NTSC versus PAL fracas in the comments, as a resident of the US we’ll stipulate that our analog color television standards were lousy. But as [standupmaths] explores in some depth, there’s a method to the madness. His chief gripe centers around the National Television System Committee’s decision to use a frame rate of 29.97 fps rather than the more sensible (for the 60 Hz AC power grid) 30 fps. We’ll leave the details to the video below, but suffice it to say that like many design decisions, this one had to do with keeping multiple constituencies happy. Or at least equally miserable. In the end [standupmaths] makes it easy to see why the least worst decision was to derate the refresh speed slightly from 30 fps.
Given the constraints they were working with, that fact that NTSC works as well as it does is pretty impressive, and quite an epic hack. And apparently inspiring, too; we’ve seen quite a few analog TV posts here lately, like using an SDR to transit PAL signals or NTSC from a microcontroller.
Filed under: classic hacks, misc hacks, video hacks
Like many of us, [Alex] spent a large part of his childhood feeding coin after coin into one arcade game or another. Galaga is one of his all-time favorites, and he has wanted to build a Galaga cabinet for a long time. Once his workshop was ready for the job, it was time to cross it off the list.
The cabinet is built to 4/5 scale. This is a great size because he gets the stability and feel of a full-size machine, but it’s much easier to move it around. As you might expect, there’s Pi in the cabinet. The display is an old TV that [Alex] found in a Dumpster. And although it works great, it would go into standby instead of powering off along with everything else. To get around this, [Alex] built an automatic remote control with an IR LED and an Arduino Diecimila. After a five-second wait, it sends the power-on code to the TV and switches the input. The TV is supposed to be in portrait mode for Galaga, but this proved to be a challenge. Changing the orientation at the Pi level resulted in poor performance and choppy sound, so he changed it at the game execution level.
We are continually impressed by the diversity of [Alex]’s builds and the care that goes into them. Who could forget his beautiful sidewalk graffiti machine or the time he showed us how to photograph stuff that’s not there? Make the jump to see a brief demonstration followed by a two-part build video.
Filed under: Raspberry Pi
MIT’s Computer Science and Artificial Intelligence Laboratory, CSAIL, put out a paper recently about an interesting advance in 3D printing. Naturally, being the computer science and AI lab the paper had a robotic bend to it. In summary, they can 3D print a robot with a rubber skin of arbitrarily varying stiffness. The end goal? Shock absorbing skin!
They modified an Objet printer to print simultaneously using three materials. One is a UV curing solid. One is a UV curing rubber, and the other is an unreactive liquid. By carefully depositing these in a pattern they can print a material with any property they like. In doing so they have been able to print mono body robots that, simply put, crash into the ground better. There are other uses of course, from joints to sensor housings. There’s more in the paper.
We’re not sure how this compares to the Objet’s existing ability to mix flexible resins together to produce different Shore ratings. Likely this offers more seamless transitions and a wider range of material properties. From the paper it also appears to dampen better than the alternatives. Either way, it’s an interesting advance and approach. We wonder if it’s possible to reproduce on a larger scale with FDM.
Filed under: 3d Printer hacks
At my university, we were all forced to take a class called Engineering 101. Weirdly, we could take it at any point in our careers at the school. So I put it off for more interesting classes until I was forced to take it in one of my final years. It was a mess of a class and never quite seemed to build up to a theme or a message. However, every third class or so they’d dredge up a veritable fossil from their ranks of graduates. These greybeards would sit at the front of the class and tell us about incredible things. It was worth the other two days of nondescript rambling by whichever engineering professor drew the short straw for one of their TAs.The patent drawing.
One greybeard in particular had a long career in America’s unending string of, “Build cool stuff to help us make bad guys more deader,” projects. He worked on stealth boats, airplanes with wings that flex, and all sorts of incredibly cool stuff. I forgot about the details of those, but the one that stuck with me was the Cyclocrane. It had a ton of issues, and as the final verdict from a DARPA higher-up with a military rank was that it, “looked dumb as shit” (or so the greybeard informed us).A Cyclo-What?
The Cyclocrane was a hybrid airship. Part aerodynamic and part aerostatic, or more simply put, a big balloon with an airplane glued on. Airships are great because they have a constant static lift, in nearly all cases this is buoyancy from a gas that is lighter than air. The ship doesn’t “weigh” anything, so the only energy that needs to be expended is the energy needed to move it through the air to wherever it needs to go. Airplanes are also great, but need to spend fuel to lift themselves off the ground as well as point in the right direction. Helicopters are cool because they make so much noise that the earth can’t stand to be near them, providing lift. Now, there’s a huge list of pros and cons for each and there’s certainly a reason we use airplanes and not dirigibles for most tasks. The Cyclocrane was designed to fit an interesting use case somewhere in the middle.
In the logging industry they often use helicopters to lift machinery in and out of remote areas. However, lifting two tons with a helicopter is not the most efficient way to go about it. Airplanes are way more efficient but there’s an obvious problem with that. They only reach their peak efficiency at the speed and direction for which their various aerodynamic surfaces have been tuned. Also worth noting that they’re fairly bad at hovering. It’s really hard to lift a basket of chainsaws out of the woods safely when the vehicle doing it is moving at 120mph.
The cyclocrane wanted all the efficiency of a dirigible with the maneuverability of a helicopter. It wanted to be able to use the effective lifting design of an airplane wing too. It wanted to have and eat three cakes. It nearly did.A Spinning Balloon with Wings
Four wings stick out of a rotating balloon. The balloon provides half of the aerostatic lift needed to hold the plane and the cargo up in the air. The weight is tied to the static ends of the balloon and hang via cables below the construction. The clever part is the four equidistant wings sticking out at right angles from the center of the ship. At the tip of each wing is a construction made up of a propellor and a second wing. Using this array of aerofoils and engines it was possible for the cyclocrane to spin its core at 13 revolutions per minute. This produced an airspeed of 60 mph for the wings. Which resulted in a ton of lift when the wings were angled back and forth in a cyclical pattern. All the while, the ship remaining perfectly stationary.There’s a really great description of its operation in the article this photo came from.
It really didn’t like strong winds.
Now the ship had lots of problems. It was too heavy. It needed bigger engines. It was slow. It looked goofy. It didn’t like strong winds. The biggest problem was a lack of funding. It’s possible that the cyclocrane could have changed a few industries if its designers had been able to keep testing it. In the end it had a mere seven hours of flying time logged with its only commercial contract before the money was gone.
However! There may be some opportunity for hackers here. If you want to make the quadcopter nerds feel a slight sting of jealousy, a cyclocrane is the project for you. A heavy lift robot that’s potentially more efficient than a balloon with fans on it is pretty neat. T2here’s a bit of reverse engineering to be done before a true performance statement can be made. If nothing else. It’s just a cool piece of aerospace history that reminds us of the comforting fact that we haven’t even come close to inventing it all yet.
If you’d like to learn more there’s a ton of information and pictures on one of the engineer’s website. Naturally wikipedia has a bit to say. There’s also decent documentary on youtube, viewable below.
Photo Credits: Rob Crimmins and Hal Denison
Filed under: news
You want to play Tetris. You want to play Tetris on any operating system. You want to play on an old IBM PC, you want to play Tetris on a new MacBook. You want a Tetris that’ll fit inside the master boot record of a disk. You want Tetris as an operating system. You want TetrOS.
Or maybe you don’t, but it’s a fantastic piece of work, and we love tiny demos. Check it out below the break. Or read through the source code in the banner image.
It doesn’t have scores, or fancy graphics, or an intro splash screen. It doesn’t show the next brick. It doesn’t speed up as you keep playing. The fatal flaw is that it doesn’t play the Tetris theme in the background. But it is tiny, and it is playable.
And speaking of Tetris without an OS, if you’ve got a comparatively spacious Arduino, you can get a version with all the frills.
Filed under: misc hacks
Meetings can actually be useful. It’s hard to believe, but they can actually save time if done right. While most of us are in a perpetual state of torture by Kevin in marketing holding another three-hour meeting during lunch hours, there are a few of us who know their hidden power when put in the right hands.
Working as a contractor, wasted meetings mean wasted billable hours. Even wasted meeting time is covered in the cost of the contract it runs the risk of giving the client the impression that you’re not as productive as originally thought. Organized, productive meetings show that you know what you’re doing and that the cost of your services as a whole is a good value. Yeah, some meetings suck but they are necessary and should be productive.
A meeting needs three things to be worth the time spent on it.
- A well prepared for, simple, and clear agenda.
- A time limit.
- Something needs to be written down at the end of it.
I’ll start with the third item as it shapes the rest. The point of a meeting is to have something to write down at the end of the meeting. Any meeting that ends up in anything requiring fallible human memory was a waste of everyone’s time. This includes, verbal agreements, handshake agreements, ideating (pronounced idioting), brainstorming, think tanking, and the like.Begin with a Clear Agenda
Productive meetings need a clear agenda. What is the meeting for?
- Can you cut out parts of it and have a shorter meeting?
- Are you making a group decision? What is that decision?
- Do you need to assign tasks? Write down the tasks you need to assign.
- Do you need to inform people of a development? Can you do it through email instead of a meeting?
- If not, as the person calling the meeting, it is your job to have all the materials ready in packets, have a well written summary of the material, and be ready to answer questions in a timely fashion.
- Do you need to “brainstorm”? If absolutely necessary, have a small meeting describing the problem, otherwise have people prepare ideas before the meeting. Then pick a direction using the meeting.
When the meeting is over everyone should get an email with all the asked questions, all the decisions, and what they should actually do with the information.
The nice part about having a clear agenda is that you can stop distraction. If you don’t have a clear agenda every small deviating discussion may appear to have worth. However, if your meeting has a goal at the end then it’s easy to say, “Hey, we’re getting distracted, can we have this discussion later, we are trying to reach a decision about X.”
For example, let’s say a client called your office and sent in the specifications of the black box they’d like ordered. Rather than tear through five hours sketching at the white board, arguing, and generally depleting brain sugar until everyone is cranky, the goal might be to quickly boil down the possible solutions to a paper list and then assign everyone clear tasks. In fact, the meeting could even be split into two. The first meeting can be fifteen minutes quickly reviewing the specs, giving people information packets, and followed by assigning the task of everyone brainstorming the most likely solutions. Then a second fifteen minute meeting in which each person’s top two ideas is written on the board, cross checked, and then assigned to people to evaluate separately.
The point is to leave with action items for each person in the group.
I am of the philosophy that any day that has more than an hour of meetings is poorly spent. If a meeting is running over forty-five minutes, it’s likely to be a total waste of time. It was probably set-up because the person doing it is stalling at a task and is hoping that either someone will solve it for them or they’ll be able to delegate it away by committee. Either that or it needs to be smaller meetings with separate distinct goals for each one.
Some of the best meetings I’ve ever been in were introduced with a time limit. The guy would wait until the room was full, look at his watch, and say, “it is now X time, in 45 minutes, or X+45, this meeting will be done.” After which he would read off his agenda, what he’d like to accomplish, and get started. After the meeting everyone would get an email describing the meeting, listing the decisions made, and explaining the tasks assigned to them. There were rarely repeat meetings.Being the Meeting-Runner
What is your duty as the person running a meeting?
- Introduce the meeting. Why is everyone here.
- Introduce people if required.
- Also, unless you have no clue who someone is, having everyone go in a circle to introduce themselves is pure torture. You should know what everyone does as part of your research, give their name, introduce them quickly, and make sure all that information is in the follow up email (because only Starfleet androids can remember eight names and titles all at once). It should take no more than five minutes unless you’re some kind of sadist.
- Keep time. Make sure the meeting doesn’t run over.
- Keep the conversation on task. If people are getting distracted it is your job to steer them back. Even if it’s the CEO of a mega-corp, it’s okay to tell them to get back to the top.
- Keep notes, or assign someone to take notes. Collect, condense, and transcribe those notes after.
- Turn those notes into correspondence. If it’s not written down and someone else doesn’t have a copy to reference it didn’t happen.
- End the meeting. If the meeting is going on too long. Call it. It probably needs to be two meetings.
To split or not to split a meeting? It’s kind of a tough call. Meetings have their place, but even if the meeting only took fifteen minutes. It’s likely to eat fifteen minutes of time in everyone’s schedule on top of the length of the meeting and at least an hour of yours if prepared for and finished off properly. The kind of meetings that actually need to be long are few. Many meetings don’t even need to be held at all with proper correspondence between team members. Meetings are a double edged sword. They’re the greatest argument in favor of a traditional office and also its greatest annoyance.
The real trick is to develop a skill for evaluating the return. If everyone’s time is billed at a hundred dollars an hour. If you have a fifteen-minute meeting with six people, then you’ve spent three hundred dollars’ worth of time: ((15 minute meeting + 15 minute interruption)/60)*100 * 6). You better have saved more than three hours of working time for your client with the meeting. If you ended up wasting it then the meeting was no good.
For example, I had a company that had thirteen separate meetings over an upgrade to their equipment that would have cost a total of three thousand dollars including labor. I once counted the time spent in one of the meetings, which included seven people, some who weren’t even in decision loop. It cost the company four thousand dollars in time. Amazing. If I were to have that same meeting over now I would have pointed that out immediately. Regardless, this eventually became the shining example in my mind of why I should quit and I don’t work there anymore.Lay it on Us, Lumbergh
In conclusion. In today’s world of instant communication and email threads it is much easier to distribute information to people working in a team — one of the main goals of having general meetings. However a well laid out meeting is still devastatingly effective. It is a thing that should be carefully prepared for and not doing so is deeply disrespectful of the time of all involved. I’m sure many of you have suffered design meetings, planning meetings, planning for the planning meetings, and the like. Let’s have your thoughts on them below.
Filed under: Business, Featured
[Martin Hubáček] wrote in with his WS2812 LED library for the STM32F3 series processors. [Martin]’s library takes the same approach as [Paul Stoffregen]’s OctoWS2811 for the Teensy, and [Erich Styger]’s for the Freescale FRDM-K64F board. That is, it uses three DMA channels to get the signal out as fast as possible.
He has a good overview of the method that you can check out for details, but it goes something like this. The WS2812 uses a PWM-like encoding to transfer data. If the signal is high for 1/3 of the time, it’s a zero, and if it’s high for 2/3 of the time, it’s a one.
The first DMA signal sends the start of a bit, setting all outputs high. The second DMA channel sends out a low signal for all of the zeros, and the third DMA channel sends out a low signal for the ones. Each of these three DMAs are clocked at just the right times to make the pulse timing work out.
The advantage of this GPIO/DMA setup over other methods is that it can drive a whole bank of pins — up to 16 strips simultaneously for the STM32F10x chips. It also loops the graphic buffer around so that you can drive repeating patterns without using much memory. And all the CPU has to do is load up the DMA buffer when it’s (half) empty, which means that even with a full load of LEDs, it’s still got most of its time left for number crunching.
Finally, to show off, [Martin] pulled a sweet trick and captured it on video. Since the digital signals are on/off encoded for the red, green, and blue channels, he decided to experiment with digital color mixing. He ands and ors two simultaneous signals together and demonstrates that it works just as you’d expect. Check it out in the video below.
Filed under: led hacks, Microcontrollers