The post Get Fit with Motivation From Your Favorite Netflix Characters appeared first on Make: DIY Projects and Ideas for Makers.
Tuesday, February 28
Get Fit with Motivation From Your Favorite Netflix Characters
Microfluidic LEGO Bricks
Years ago, prototyping microfluidic systems was a long, time-intensive task. With inspiration from DIY PCB fabrication techniques, that time is now greatly reduced. However, even with the improvements, it still takes a full day to go from an idea to a tangible implementation. However, progress creeps in this petty pace from day to day, and in accordance, a group of researchers have found a way to use 3D printed molds to create microfluidic LEGO bricks that make microfluidic prototyping child’s play.
For the uninitiated, microfluidics is the study and manipulation of very small volumes of water, usually a millionth of a liter and smaller (nL-pL). Interestingly, the behavior of fluids at small scales differs greatly from its larger scale brethren in many key ways. This difference is due to the larger role surface tension, energy dissipation, and fluidic resistance play when distances and volumes are minimized.
By using 3D printed molds to create microfluidic bricks that fit together like LEGOs, the researchers hope to facilitate medical research. Even though much research relies on precise manipulation of minuscule amounts of liquid, most researchers pipette by hand (or occasionally by robot), introducing a high level of human error. Additionally, rather than needing multiple expensive micropipettes, a DIY biohacker only needs PDMS (a silicon-based chemical already used microfluidics) and 3D printed molds to get started in prototyping biological circuits. However, if you prefer a more, ahem, fluid solution, we’ve got you covered.
[via Adafruit]
Filed under: chemistry hacks
Understanding DMA
In the world of computers, the central processing unit (CPU) is–well–central. Your first computer course probably explained it like the brain of the computer. However, sometimes you can overload that brain and CPU designers are always trying to improve both speed and throughput using a variety of techniques. One of those methods is DMA or direct memory access.
As the name implies, DMA is the ability for an I/O device to transfer data directly to or from memory. In some cases, it might actually transfer data to another device, but not all DMA systems support that. Sounds simple, but the devil is in the details. There’s a lot of information in this introduction to DMA by [Andrei Chichak]. It covers different types of DMA and the tradeoffs involved in each one.
DMA is especially useful for transferring blocks of data (for example, data from a disk drive, audio, or video data) at high speeds. It is also useful for slow data (like UARTs) so that the CPU doesn’t have to block itself waiting for a slow I/O device. In the old days, sometimes the processor wasn’t fast enough to read a fast stream, but today it is likely that the processor is super fast. You just don’t want to tie it up with a slow I/O device. But that has changed how DMA architectures work over time. Usually, when a block transfer completes, the CPU gets a single interrupt so it can process the incoming data or queue up more data to send to the device.
The primary way to differentiate DMA schemes is what happens to the processor while the memory is in use by another device. An older processor is likely to use block mode where the processor simply stalls while the memory is in use. That makes sense because the I/O device is probably faster than the CPU anyway so the loss in terms of executed instructions will be small.
With faster processors, burst mode DMA is popular because it will limit how long the CPU is paused. In fact, many modern burst controllers will try to wait until the CPU is not using memory anyway and only stall if the CPU tries to use memory during the brief transfer.
Some processors and DMA systems can figure out when the CPU will not be using memory for a bit and do transfers totally during that time. This is usually known as transparent mode.
You might think that DMA is for “big computers,” and certainly, [Andrei’s] article centers on PC’s, SPARC, and Atmel SAM devices. However, block mode DMA on an 8085 (with an external controller) is also mentioned. We also remember that the RCA 1802 had DMA on the CPU which was amazing in its day. That DMA is what made a simple front panel possible for the ELF computers and a cool (for its day) video graphics chip. Admittedly, if you are writing with a modern operating system and you aren’t writing device drivers, you probably don’t need to use DMA. But for real-time systems you can easily analyze, DMA can be both a great simplification and a boost to overall system throughput.
While this intro has a lot of background, it doesn’t show any real concrete examples. If you want to see [Mike Harrison’s] practical results of using DMA for SPI on a PIC32, be sure you read our post on that from last year.
Filed under: ARM, Microcontrollers
Researchers find “severe” flaw in WordPress plugin with 1 million installs
More than 1 million websites running the WordPress content management system may be vulnerable to hacks that allow visitors to snatch password data and secret keys out of databases, at least under certain conditions.
The vulnerability stems from a "severe" SQL injection bug in NextGEN Gallery, a WordPress plugin with more than 1 million installations. Until the flaw was recently fixed, NextGEN Gallery allowed input from untrusted visitors to be included in WordPress-prepared SQL queries. Under certain conditions, attackers can exploit the weakness to pipe powerful commands to a Web server's backend database.
"This is quite a critical issue," Slavco Mihajloski, a researcher with Web security firm Sucuri, wrote in a blog post published Monday. "If you're using a vulnerable version of this plugin, update as soon as possible."
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More states introduce bills to interfere with science education
At the start of this month, we covered a bill making its way through the South Dakota legislature. It's the latest variation on a large collection of state bills that seek to protect educators from what has been termed "teaching the controversy." Should the bills pass, teachers would be immune to punishment for using outside material in instruction, as long as the teacher believes the material is scientific—even if it has overtly religious origins.
But in the intervening time, similar bills have appeared in three other states, and a fourth state is considering eliminating references to climate change in its teaching plan. Science education appears to be facing a busy year in the statehouses.
We can start with Indiana, where Senate Resolution 17 has now cleared the Education Committee. The resolution approvingly quotes a proposed amendment to the No Child Left Behind Act to challenge evolution: "Where topics are taught that may generate controversy (such as biological evolution), that the curriculum should help students to understand the full range of scientific views that exist, why such topics can generate controversy, and how scientific discoveries can profoundly affect society." What it neglects to note is that the amendment was rejected or that evolution is the only scientific view that currently exists.
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First trailer for Okja proves that giant monsters can always get weirder
The first teaser trailer for Bong Joon-ho's new kaiju flick, Okja.
Okja is the result of Netflix giving Bong $50 million and complete artistic freedom, and the results look just as bizarre as you might hope. The movie stars Ahn Seo-hyun, Tilda Swinton, and Giancarlo Esposito, among others.
The central struggle is between image-obsessed corporate scientist Nancy Mirando (Swinton) and a girl named Mija (Ahn). In this teaser trailer, we hear Nancy proclaim that she's put science and nature together to create something extraordinary. But that "something" is Mija's best friend, who also happens to be a giant monster. We only see a glimpse of the monster, but if Bong's previous monster movie The Host is any indication, this megabeast is going to look great.
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Tesla Model S Battery Pack Teardown
We’ve heard a lot about the Tesla Model S over the last few years, it’s a vehicle with a habit of being newsworthy. And as a fast luxury electric saloon car with a range of over 300 miles per charge depending on the model, its publicity is deserved, and that’s before we’ve even mentioned autonomous driving driver-assist. Even the best of the competing mass-produced electric cars of the moment look inferior beside it.
Tesla famously build their battery packs from standard 18650 lithium-ion cells, but it’s safe to say that the pack in the Model S has little in common with your laptop battery. Fortunately for those of a curious nature, [Jehu Garcia] has posted a video showing the folks at EV West tearing down a Model S pack from a scrap car, so we can follow them through its construction.
The most obvious thing about this pack is its sheer size, this is a large item that takes up most of the space under the car. We’re shown a previous generation Tesla pack for comparison, that is much smaller. Eye-watering performance and range come at a price, and we’re seeing it here in front of us.
The standard of construction appears to be very high indeed, which makes sense as this is not merely a performance part but a safety critical one. Owners of mobile phones beset by fires will testify to this, and the Tesla’s capacity for conflagration or electrical hazard is proportionately larger. The chassis and outer cover are held together by a huge array of bolts and Torx screws, and as they comment, each one is marked as having been tightened to a particular torque setting.
Under the cover is a second cover that is glued down, this needs to be carefully pried off to reveal the modules and their cells. The coolant is drained, and the modules disconnected. This last task is particularly hazardous, as the pack delivers hundreds of volts DC at a very low impedance. Then each of the sixteen packs can be carefully removed. The packs each contain 444 cells, the pack voltage is 24 V, and the energy stored is 5.3 kWh.
The video is below the break. We can’t help noticing some of the rather tasty automotive objects of desire in their lot.
We’ve shown you a Model S teardown before, but without a video. For comparison, take a look at teardowns of a Nissan Leaf pack, and the NiMH pack from a Ford Fusion hybrid.
Via Hacked Gadgets.
Filed under: car hacks
Finally, VR has a legitimate RTS contender in Brass Tactics
SAN FRANCISCO—That real-time strategy battling is a solid fit for virtual reality seems like a foregone conclusion. RTS games like Total Annihilation and Starcraft already force players to gaze at their little fighters, armies, and fortifications from high above. So why not let us use VR systems to control all of those battles with our hands, like wartime puppeteers, with greater speed and accuracy than a mouse-and-keyboard could ever give?
The developers of Brass Tactics, the first major RTS for the Oculus Touch platform, say that there's a reason gamers haven't seen a major game in the genre in VR's early days. "Real-time strategy is already hard to make," Hidden Path Entertainment co-founder Mark Terrano says. "Virtual reality only adds more challenge."
But, by golly, Hidden Path may very well have nailed the formula with its still-in-development game Brass Tactics—and well before any other game developer has launched anything remotely as slick.
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Ask Hackaday: What’s Your Etchant?
Although the typical cliché for a mad scientist usually involves Bunsen burners, beakers, and retorts, most of us (with some exceptions, of course) aren’t really chemists. However, there are some electronic endeavors that require a bit of knowledge about chemistry or related fields like metallurgy. No place is this more apparent than producing your own PCBs. Unless you use a mill, you are probably using a chemical bath of some sort to strip copper from your boards.
The standard go-to solution is ferric chloride. It isn’t too tricky to use, but it does work better hot and with aeration, although neither are absolutely necessary. However, it does tend to stain just about everything it touches. In liquid form, it is more expensive to ship, although you can get it in dry form. Another common etchant is ammonium or sodium persulphate.
When [w_k_fay] ran out of PCB etchant, he decided to make his own to replace it. He complained that he found a lot of vague and conflicting information on the Internet. He read that the vinegar solution was too slow and the cupric acid needs a heated tank, a way to oxygenate the solution, and strict pH controls. However, he did have successful experiments with the hydrochloric acid and peroxide. He also used the same materials (along with some others) to make ferric chloride successfully.
A common theme in etchants is to use hydrogen peroxide as an oxidant. The problem is, what you get in the drug store isn’t all that strong. In general, the higher the concentration of peroxide the stronger the solution. You can freeze 3% peroxide to increase the concentration or go to a beauty supply store and by peroxide at higher concentrations, but it will cost more. Of course, if you’re diluting the acid with water anyway, the peroxide concentration may be moot.
Speaking of cost, some of these solutions are cheap, but it isn’t like premade etching solution is that expensive either. However, sometimes the commercial chemicals are hard to source locally, so that may be more of an inducement to homebrew.
So the question for all Hackaday readers is a simple one: what do you use to etch your boards? A commercial solution? Something homebrew? A CNC machine? (Well, that doesn’t really count for the purpose of this question, but we’ll take the answer anyway.) We suppose plasma etching doesn’t count, either, but it would be interesting to know if anyone’s doing that. Leave a comment with what you are using and why.
Just to remind you, copper etching isn’t just for electronics. That’ll give you something to do with your etchant when you decide to just start sending your boards out.
Filed under: chemistry hacks, Featured, tool hacks
Tesla’s P100D: I got 99 problems but not being able to go really fast ain’t one
Jonathan Gitlin
To coincide with the opening of its newest store in Washington, DC, Tesla asked us if we'd like to spend a few days with one of its latest Model S P100Ds. However, there was just one catch; we'd have to do all the driving ourselves. As one of the newest cars off the production line, this Model S was equipped with Tesla's own self-driving sensors (known in Tesla-world as HW2), but the company is still in the process of pushing out the software necessary to enable Autopilot in these cars. Scratch that plan of road-tripping up to New York—a proper test of the new Autopilot will have to wait.
Autopilot may have been absent, but this P100D did have a rather special trick up it's sleeve: an easter egg that makes Ludicrous Mode even more, well, ludicrous. So, rather than try out the P100D's humongous (for an electric vehicle) range—315 miles according to the EPA—we spent our days finding out just how fast it really is. The answer? Ludicrously fast.
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Amazon’s Alexa could soon recognize users by their voices
(credit: Adam Bowie)
Amazon's Alexa is may be about to get smarter. According to a report from Time, the online retailer is working on voice identification software for Alexa which would allow it to identify who in a household is speaking to it. "People familiar with Amazon's Alexa strategy" claim this feature has been under development since 2015, and the challenge now is to strategically integrate it into Alexa devices like Amazon Echo.
The report claims the feature is internally called Voice ID and it would match a person's voice to a prerecorded "voice print" to identify who is talking. The primary account holder could limit specific actions to only those matching a specific voice print. For example, any voice-made purchases could be limited to parents in a household so children don't go on voice-enabled shopping sprees.
Alexa, and other voice assistants including Apple's Siri, Google's Assistant, and Microsoft's Cortana, all essentially do the same thing: they respond to voice commands and can answer questions like "How's the weather?" or "What's on my calendar today?" However, none can decipher who is doing the talking—and in homes where a device is linked to multiple accounts, that could become problematic. Amazon Alexa can already swatch between different user accounts, but the speaker must say "Switch accounts" or use the Alexa app to do so.
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Sony’s Xperia Touch projector turns any surface into an Android device
BARCELONA—Not every device at Mobile World Congress is a phone or tablet—Sony is launching the "Xperia Touch" a portable short-throw laser projector that turns any surface into a touchable Android device. Sony has shown off the device at various tech conferences as a "concept," but in Barcelona, Sony is announcing the device as a real product, albeit for the eye-popping price of €1,499 ($1,588).
The device is a 134mm × 143mm × 69 mm (5.3 × 5.6 × 2.7 inches) metal box with all the usual smartphone parts, but instead of a screen, it has a laser LCoS laser projector with auto focus. As the name implies, the Xperia Touch also supports touch controls, through a combination of an IR array and a 60fps camera,
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Wireless HTC Vive tested: One of VR’s problems solved, but two remain
Andrew Williams
BARCELONA, Spain—VR has the potential to be a very exciting technological domain, but it's lumbered with numerous problems: high price, low performance, and generally the sheer pain-in-the-backside factor, particularly with more advanced setups like the HTC Vive or Oculus Rift. At MWC 2017 we tried two solutions that evaporate the physical connection between headset and PC, mostly mitigating the last of those three issues.
The two solutions are DisplayLink XR, made by DisplayLink, and TPCast, which appears to be made by a company called TPCast. We wrote about the latter back in November 2016 when it was first announced in China. Now we’ve physically tried them both.
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7 Useful Mods to Upgrade Your Smart Phone Camera
The post 7 Useful Mods to Upgrade Your Smart Phone Camera appeared first on Make: DIY Projects and Ideas for Makers.
New holster forces all nearby body cams to start recording when gun is pulled
Axon, the body cam division of Taser International, has announced Signal Sidearm, a gun holster sensor that detects when a weapon has been removed from a holster and automatically prompts all nearby body cams to start recording.
The Signal Sidearm, despite its slightly confusing name and provided artwork, isn't a pricey, complex smart weapon, but rather a sensor that can be retrofitted into "most existing firearm holsters." The sensor is powered by a coin cell battery that lasts approximately 1.5 years. It sounds like the sensor is technologically very simple, which hopefully means it's also very reliable.
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