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ถูกปรับปรุง 3 hours 4 min ก่อน

This (mostly) Transparent Tesla Coil Shows It All

5 hours 26 minก่อน

You’d be forgiven for assuming that a Tesla coil is some absurdly complex piece of high-voltage trickery. Clarke’s third law states that “any sufficiently advanced technology is indistinguishable from magic”, and lighting up a neon tube from across the room sure looks a lot like magic. But in his latest Plasma Channel video, [Jay Bowles] tries to set the record straight by demonstrating a see-through Tesla coil that leaves nothing to the imagination.

Of course, we haven’t yet mastered the technology required to produce transparent copper wire, so you can’t actually see through the primary and secondary coils themselves. But [Jay] did wind them on acrylic tubes to prove there aren’t any pixies hiding in there. The base of the coil is also made out of acrylic, which lets everyone see just how straightforward the whole thing is.

Beyond the coils, this build utilizes the DIY high-voltage power supply that [Jay] detailed a few months back. There’s also a bank of capacitors mounted to a small piece of acrylic, and a clever adjustable spark gap that’s made of little more than a few strategically placed pieces of copper pipe and an alligator clip. Beyond a few little details that might not be obvious at first glance, such as grounding the secondary coil to a layer of aluminum tape on the bottom of the base, it’s all right there in the open. No magic, just science.

[Jay] estimates this beauty can produce voltages in excess of 100,000 volts, and provides a demonstration of its capabilities in the video after the break. Unfortunately, before he could really put the new see-through coil through its paces, it took a tumble and was destroyed. A reminder that acrylic enclosures may be pretty, but they certainly aren’t invulnerable. With the value of hindsight, we’re sure the rebuilt version will be even better than the original.

If you’d rather not have your illusions shattered, we’ve seen plenty of complex Tesla coils to balance this one out. With witchcraft like PCB coils and SMD components, some of them still seem pretty magical.

Untethered: Fishing Without Lines

6 hours 56 minก่อน

There’s a laundry list of ways that humans are polluting the earth, and even though it might not look like it from the surface, the oceans seem to bear the brunt of our waste. Some research suggests that plastic doesn’t fully degrade as it ages, but instead breaks down into smaller and smaller bits that will be somewhere the in environment for such a long time it could be characterized in layman’s terms as forever.

Not only does waste of all kinds make its way to the oceans by rivers or simply by outright dumping, but commercial fishing gear is estimated to comprise around 10% of the waste in the great blue seas, and one of the four nonprofits help guide this year’s Hackaday Prize is looking to eliminate some of that waste and ensure it doesn’t cause other problems for marine life. This was the challenge for the Conservation X Labs dream team, three people who were each awarded a $6,000 micro-grant to work full time for two months on the problem.

It isn’t about simply collecting waste in the ocean, but rather about limiting the time that potentially harmful but necessary fishing equipment is in the water in the first place. For this two-month challenge, this team focused on long lines used by professional fishing operations to attach buoys to gear like lobster pots or crab traps. These ropes are a danger to large ocean animals such as whales when they get tangled in them and, if the lines detach from the traps, the traps themselves continue to trap and kill marine life for as long as they are lost underwater. This “ghost gear” is harmful in many different ways, and reducing its time in the water or “soak time” was the goal for the project.

Let’s take a closer look at their work after the break, and we can also see the video report they filed as the project wrapped up.

Preventing Ghost Gear From Haunting the Seas

The first solution to this issue is a method by which fishermen can accurately locate their equipment. The team designed a ropeless trap marking system that attaches to a trap underwater, which would eliminate the need for a permanent fixed rope attached to a traditional buoy. The design includes a smart buoy that stays attached to the trap until its ready to be released, and then at the right moment, presumably when the trap is full, the buoy is released and is able to float up to the surface. While not truly “ropeless” since the buoy spools out a line as it makes its way to the surface, it does dramatically reduce the amount of time that the rope is actively dangling in the water where any passing animal can get snagged on it, and therefore also reduces the chances that the trap is lost as a result of a broken line.

The current prototype for the smart buoy is housed in a Nalgene bottle, which is made out of strong plastic capable of withstanding pressures to around 160 meters of depth. Inside the bottle is a set of electronics that make locating the buoy much easier. Each version contains a GPS module, a LoRa radio module, and an ESP32 to tie it all together, plus a battery and charging circuitry. One of the prototype boards additionally contains a cellular modem for additional tracking abilities.

Retrieving the Equipment in One Piece

Of course the buoy is not going to be able to communicate with much of anything while it’s sleeping with the fishes, so it also houses a set of magnetic wipers within its protective Nalgene case that keep it secured to the submerged trap. When it senses that it is time to deploy, a small motor moves the magnets which release it from its external housing mechanism. From there it can simply float to the surface while it deploys a small rope from a spool that’s also housed on the device. The device can communicate easily with its various included hardware to an on-boat gateway or to a properly-equipped cell phone.

Currently the prototype smart buoy deploys itself after a set amount of time has elapsed; in the video demonstration it is set to deploy every two minutes so that it can be tested quickly. In a real-world scenario though it could keep the timer feature and simply deploy at the end of the day, but the amount of electronics in the buoy allows for a number of other options for deploying itself that the team hopes to expand upon in the future. Other planned upgrades include using LEDs in the buoy to aid in location, and using cameras in the bottle to make determinations about the state of the trap. Some cameras were used in testing in Lake Ontario and the results showed that this will likely be a difficult problem to solve.

Development Requires Cooperation

Perhaps the most important part of this project isn’t technology-based at all, but focuses on ensuring adoption of this technology by fishermen. These intelligent buoys have to be cost effective and simple to use. Since ghost gear costs them money as well, in terms of lost equipment, lost catch, and the long-term damage to the environment that is caused as a result, the team plans to work closely with the fishermen to make sure that all of their concerns about the equipment are addressed and their needs are met, both from a technology point-of-view but also from one of usability and economics.

There are certainly more questions to answer and more problems to solve, but this project has a promising start and will certainly help the declining situations in the oceans when it can be fully developed and implemented. We look forward to seeing Conservation X Labs’ future designs and solutions.

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Lewis Latimer Drafted the Future of Electric Light

8 hours 26 minก่อน

These days, we have LED light bulbs that will last a decade. But it wasn’t so long ago that incandescent lamps were all we had, and they burned out after several months. Thomas Edison’s early light bulbs used bamboo filaments that burned out very quickly. An inventor and draftsman named Lewis Latimer improved Edison’s filament by encasing it in cardboard, earning himself a patent the process.

Lewis had a hard early life, but he succeeded in spite of the odds and his lack of formal education. He was a respected draftsman who earned several patents and worked directly with Alexander Graham Bell and Thomas Edison. Although Lewis didn’t invent the light bulb, he definitely made it better and longer-lasting.

Lewis in 1882, the year after he improved Edison’s light bulb. Image via Wikipedia Born Free

Lewis Howard Latimer was born September 4th, 1848 in Chelsea, Massachusetts, near Boston. He was the youngest of four children. Lewis’ parents, George and Rebecca, had been slaves in Virginia, but Lewis was born in free territory.

Eight years before Lewis was born, his parents escaped to the north on a steamer, but George was captured in 1842 when someone who knew his former owner spotted him on the street. His plight caught the attention of abolitionist leaders who raised money from the citizens of Boston to purchase George’s freedom. By this time, Rebecca was pregnant with George junior.

In Chelsea, George worked as a wallpaper-hanger and also owned a barbershop. Lewis helped his father with both until George disappeared when Lewis was 10 years old. The Emancipation Proclamation was still a few years away, and it is thought that he was tired of worrying about being recaptured and went underground.

At 13, Lewis got a job as an office boy in an attorney’s office. He lied about his age and joined the Union Navy at age 15, but was honorably discharged about a year later. He helped his mother clean houses for a while, and then found out that the patent office of Crosby & Gregory was looking for a boy with a taste for drawing. Lewis had always liked drawing and jumped at the opportunity.

Bell’s original telephone patent. Image via US Patent #174465 Drafting the Future

At Crosby & Gregory, Lewis provided a constant shadow for the company’s draftsman whenever he could spare a second between office duties. He soon bought a set of secondhand tools and books, and practiced technical drawing in his spare time. Eventually, the draftsman let him do some sample drafting. They were impressed with Lewis’ skills, and when the draftsman resigned, Lewis got the job.

Drafting patents requires that the artist and the inventor work closely together. Because of this, Lewis learned about a lot of things and was well-versed in the the technical and legal aspects of patents by the 1870s. Lewis applied for his own patent for the first time in 1874 — an improvement for water closets in railroad cars. It was deemed too insignificant for a patent.

In the mid-1870s, his firm was working on patents for Alexander Graham Bell’s telephone, and Lewis Latimer was drafting all the technical drawings. In keeping with the lore about Bell’s work and sleep habits, legend has it that Lewis had to wait until after 9PM each night for Bell to be available to give him his instructions.

Lewis left Crosby & Gregory in 1878 because of management changes. During this time he worked a few jobs slinging wallpaper paste like his father before him and relocated with his wife Mary Wilson (whom he wed in 1873) and two daughters to Bridgeport, Connecticut where his sister lived. There he would eventually land a drafting job at Fallandsbee Machine Shop.

The Draw of Electric Light

After Thomas Edison received a patent for the light bulb in 1879, electric lighting began to quickly taking over gas lighting. Historians suggest that Lewis had become enamored by electric light and believed it was the future. It was certainly in his future.

One day, Hiram Maxim, owner of the United States Electric Lighting Company strolled into the machine shop. He saw Lewis sitting there drafting and was intrigued. Maxim asked him a bunch of questions and by the end of the conversation, he’d hired Lewis as his draftsman and general assistant.

Lewis’ patent for the manufacture of improved carbon filaments. Image via US Patent #252386

Lewis started at the two-year-old company in 1880. Maxim was trying to make light bulbs, the hot new gadget of the times. He and his partner William Sawyer had incandescent lamp patents, and theirs was only the second to market after Edison’s.

Maxim’s process for treating filaments included a hydrocarbon vapor that equalized and standardized resistance. It also made them burn longer than the Edison filaments, which were made of bamboo. Lewis perfected a way to produce these filaments without breaking, as they were prone to do. He suggested using a material with the same rates of expansion and contraction as the filament blanks. Lewis received a patent for this method in 1882.

Although U.S. Electric’s lamps had a longer-lasting filament, they didn’t beat Edison because they didn’t have the scientific method down, doing mostly guesswork instead. While US Electrical focused on a quality lamp, Edison wanted complete vertical integration of the electrical world from the filament to the dynamo.

Like many 1880s startups, U.S.Electric was one among many small companies vying for light bulb market share. Lewis was terribly important to the operation and likely the only draftsman that Maxim had and his value extended far beyond the drawing table. He had the great responsibility of overseeing lighting installations, which requires a lot of knowledge. In 1881, Lewis became superintendent of the incandescent lamp department, overseeing 40 workers.

Around this time, U.S. Electric merged with Weston Electric. Lewis was sent to England to oversee a large lighting installation. Although the workers didn’t care to take orders from a black man at first, he eventually won them over. When his contract was up in England, he and Mary moved back to the States, but there was no job to come back to. He moved from company to company for a while and wound up at Olmstead Electrical in Brooklyn as draftsman and manager of lamp fabrication. Lewis convinced them to manufacture his lamp, but it never received a patent and wasn’t commercially successful.

The founding members of the Edison Pioneers. Image via Wikipedia Edison’s Pioneers

In 1884, Lewis was hired by the Edison company to be their chief draftsman and expert witness as to the facts as they related to the early stages of the electric light business. In other words, he helped Edison prosecute patent infringers. The only suit that went anywhere was the one against Lewis’ old company, U.S. Electrical, which Edison won. In 1889, Lewis joined the Edison legal department, though he still had drafting duties.

General Electric was created when Thomson-Houston and Edison Electrical merged on April 15, 1892. Westinghouse remained heir biggest competitor. By 1896, there were 300+ lawsuits pending between the GE and Westinghouse. They finally reached an agreement in 1896 and pooled the bulk of their patents, with GE retaining their own incandescent lamp patents.

Lewis was asked to join the Edison Pioneers, a group of twenty-eight men who had been integral to the development of the light bulb up to and including 1885. He was bestowed this honor despite never working in Edison’s laboratory itself, and was the only African-American member. In 1890, Lewis published Incandescent Electric Lighting, a practical description of the Edison system.

Lewis died December 11, 1928 after a lengthy illness. He was 80 years old.

Arduino Bobbin Winding Machine is Freaky Fast

อังคาร, 10/20/2020 - 22:30

One of the worst things about sewing is finding out that your bobbin — that’s the smaller spool that works together with the needle and the larger spool to make a complete stitch — ran out of thread several stitches ago. If you’re lucky, the machine has a viewing window on the bobbin so you can easily tell when it’s getting dangerously close to running out, but many machines (ours included) must be taken halfway apart and the bobbin removed before it can be checked.

Having spare bobbins ready to go is definitely the answer. We would venture to guess that most (if not all) machines have a built-in bobbin winder, but using them involves de-threading the machine and setting it up to wind bobbins instead of sew. If you have a whole lot of sewing to do and can afford it, an automatic bobbin winder is a godsend. If you’re [Mr. Innovative], you build one yourself out of acrylic, aluminium, and Arduinos.

Here’s how it works: load up the clever little acrylic slide with up to twelve empty bobbins, then dial in the speed percentage and press the start button. The bobbins load one at a time onto a drill chuck that’s on the output shaft of a beefy 775 DC motor. The motor spins ridiculously fast, loading up the bobbin in a few seconds. Then the bobbin falls down a ramp and into a rack, and the thread is severed by a piece of nichrome wire.

An important part of winding bobbins is making sure the thread stays in place at the start of the wind. We love the way [Mr. Innovative] handled this part of the problem — a little foam doughnut around a bearing holds the thread in place just long enough to get the winding started. The schematic, BOM, and CAD files are available if you’d like to make one of these amazing machines for yourself. In the meantime, check out the demo/build video after the break.

Still not convinced that sewing is cool enough to learn? Our own [Jenny List] may be able to convert you. If that doesn’t get you, you might like to know that some sewing machines are hackable — this old girl has a second life as a computerized embroidery machine. If those don’t do it, consider that sewing machines can give you a second life, too.

Thanks for the tip, [Baldpower]!

Mazda Investing Big In Advanced Gasoline Tech With Skyactiv-X

อังคาร, 10/20/2020 - 21:00

Electric cars, as a concept, were once not dissimilar from the flying car. Promised to be a big thing in the future, but hopelessly impractical in the here and now. However, in the last ten years, they’ve become a very real thing, with market share growing year on year as new models bring greater range and faster charging times.

With their lower emissions output and ever-improving performance, one could be forgiven for thinking that traditional combustion engines are all but dead. Mazda would beg to differ – investing heavily in new technology to take the gasoline engine into the next decade and beyond.

The Best Of Both Worlds Mazda have offered diesel engines across their range in recent years. Image credit: Mazda

The holy grail of efficient combustion engines lies not with petrol, but with diesel engines. They routinely hit thermal efficiencies of over 40%, compared to the typical automotive gasoline engine which comes in closer to just 20%. This all comes down to the low volatility of diesel fuel. This enables diesel engines to run at very lean air/fuel ratios and incredibly high compression ratios, without the mixture prematurely detonating and damaging the engine or wasting power. It also enables the use of compression ignition, where the rising pressures inside the cylinder ignite the air/fuel mixture almost instantaneously, all at once.

Petrol engines, in comparison, have to carefully keep their air/fuel ratio much richer, from the stoichiometric level of 14:1, up to 9:1 under some conditions. This is to ensure the fuel doesn’t detonate instead of burning smoothly in a controlled manner. A sparkplug must be used to initiate ignition, with the flame front slowly moving through the mixture versus the instantaneous nature of compression ignition. Gas engines also run at much lower compression ratios – with a maximum of 14:1 seen in practice. Other factors also play a role, but mixture and compression ratio are the primary reasons diesel has such an advantage over gasoline in the efficiency stakes.

Over the years, many manufacturers have attempted to get gasoline engines to operate under compression ignition conditions. While several manufacturers have been able to make this work at low-RPM, low-load conditions. Under harder driving, the higher compression ratios required simply cause the air/fuel mixture to detonate, damaging the engine.

An Incredibly Complex Solution SPCCI combustion uses a spark plug to ignite a small region of rich fuel/air mix to raise the cylinder pressure high enough to push the rest of the mixture into compression ignition. Illustration: Alex On Autos

Despite the difficulties, Mazda managed to build a production-ready compression-ignition gasoline engine, by the name of Skyactiv-X. Unlike previous attempts, it includes a spark plug in a creative hack that they call Spark Controlled Compression Ignition, or SPCCI, as explained in this excellent video by Alex On Autos.

When running in this mode, the engine runs an incredibly lean air fuel mixture, on the order of 29:1 – so lean, even the engine’s high compression ratio of 16:1 won’t cause the mixture to combust.  When the piston is reaching the top of the compression stroke, a small amount of extra fuel is injected, next to the spark plug. This localized richer mixture is ignited by the spark plug, with the combustion causing an increase of pressure in the cylinder. This added pressure then causes the rest of the mixture to undergo compression ignition. The result is a gasoline engine that can run at a higher compression ratio with a leaner air-fuel mixture than is traditionally possible. The target ratio is so lean that a low-pressure supercharger is used as a pump to supply more air to the combustion chamber.

The SPCCI regime is incredibly efficient, but when high power is required, it makes more sense to run the engine in a typical spark-ignition mode. With a compression ratio of 16:1, however, this would normally be difficult to achieve without detonation. However, modern variable valve timing enables the engine to leave the intake valve open during part of the compression stroke when operating in spark ignition mode. This reduces the engine’s effective compression ratio, allowing it to drop to a point suitable for traditional spark-ignition operation. This allows the engine to smoothly transition between SPCCI and conventional operation, something other manufacturers have thus far failed to achieve.

All this should add up to an engine that makes gains in efficiency, as well as power and torque. Mazda claims a fuel economy improvement of anywhere from 20 to 30% over their previous engines, and 30% more torque. Sadly, the data we’ve seen doesn’t entirely bear this out.

Looking at actual peak figures, the real numbers seem a touch underwhelming. Comparing the 2.0L Skyactiv-X to the previous 2.0L Skyactiv-G, we see a gain of just 12% in peak torque and 14% in peak power. However, this doesn’t take into account performance across the RPM band, and it’s possible that torque gains are much larger in the lower RPM range. As far as fuel economy is concerned, a 3-hour real world test didn’t show a whole lot of difference between the Skyactiv-X and the previous Skyactiv-G. Take into account that the Skyactiv-X also packs a mild hybrid system, and this is fairly disappointing. We’d like to look at this comparison again when the technology is a little more mature, but it’s a concerning result to say the least.

Of course, The sheer complexity of what Mazda has achieved should not be understated. Producing a production-ready, mass produced engine that can smoothly transition between compression ignition modes and regular spark ignition requires the combination of a swathe of technologies, from advanced computer engine controls, to direct injection and variable valve timing. The investment required in research and development to complete such a project is immense; the fact that no other automaker has achieved the feat should indicate the level of difficulty in mastering gasoline compression ignition.

It’s All About Return on Investment In a direct comparison, the new engine adds significant power and torque, but fuel economy gains haven’t been borne out in real world testing. Image: Whichcar

Despite strong holds on some unique markets like Australia, Mazda remains one of the smaller automakers on the world stage. In vehicles produced, they ranked just 17th in the world, delivering 1.6 million vehicles in 2017. Unlike many other manufacturers, they are not part of a larger consortium, standing largely alone in a field dominated by heavy hitters like Toyota, Fiat-Chrysler, and Nissan-Renault-Mitsubishi. This makes their achievement all the more surprising, given the investment required and the resources available to this David amongst Goliaths.

It raises some eyebrows that Mazda has dedicated so many resources to the ongoing development of the gasoline engine, with many betting on an unstoppable wave of electric vehicles taking over market share in years to come. Other major players like Mercedes have already made moves to end development of gasoline engines. On top of this, with some cities looking to ban fossil fuel vehicles entirely in years to come, one wonders how much Mazda will be able to recoup the development cost over the next decade. Mazda’s own projections state that gasoline engines will still power 85% of all cars in 2035, but the more important figure is the proportion of new sales held by gasoline powered vehicles. BloombergNEF’s modelling expects to see electric cars take a 28% share of new car sales by 2030, so it seems there will still be plenty of time left for Mazda to cash in. It also serves as a useful gap-filler while the company begins a transition towards electric technology.

However, if SPCCI technology is to do well in the marketplace, it will have to make good on its lofty claims. While the new engine certainly packs better power and torque, it hasn’t yet shown a meaningful increase in fuel economy which is supposed to be one of its major benefits. And no matter how new and fancy it is, it can’t compete in the shiny, futuristic stakes with all-electric vehicles. Similar to Mazda’s prior experiments with Miller cycle engines in the 1990s, we suspect this may be more of an interesting blip than a game-changer for the gasoline engine. As always, time will tell.

 

Thinking about Creating a Raspberry Pi Replacement?

อังคาร, 10/20/2020 - 18:00

If you’ve ever wanted to try your hand at creating a Raspberry Pi-like board for yourself, you should check out [Jay Carlson’s] review of 10 different Linux-capable SoCs. Back in the 1960s, a computer was multiple refrigerator-sized boxes with thousands of interconnections and building one from scratch was only a dream for most people. Then ICs came and put all the most important parts in a little relatively inexpensive IC package and homebrew computing became much more accessible. Systems on Chip (SoC) has carried that even further, making it easier than ever to create entire systems, like the Pi and its many competitors.

Only a few years ago, making an SoC was still a big project because the vendors often didn’t want to release documentation to the public. In addition, most of the parts use ball grid array (BGA) packaging. BGA parts can be hard to work with, and require a multilayer PC board. Sure, you can’t plug these into a typical solderless breadboard. But working with these relatively large BGAs isn’t that hard and multilayer boards are now comparatively cheap. [Jay] reports that he got cheap PCBs and used a hot plate to build each board, and has some sage advice on how to do it.

Although he’s looking at 10 different chips, he wound up making about 25 boards and he deliberately avoided using example PCB layouts. This let him optimize for hand assembly and try a few different strategies for things like memory layout. [Jay] points out the boards are more for evaluation than use. He didn’t put any peripherals onboard that you would probably want in a working system. He only included what was necessary to boot the chip into Linux.

There’s a long part of the post where [Jay] talks about why you might want to use Linux, why you might not want to use Linux, and why the Raspberry Pi 4 might not be your best choice, depending on your design goals. He also gives a tutorial on simplified single-chip DDR memory layout.

This has a reputation of being difficult to do, and the post acknowledges that for multip-chip designs, it is harder. However, at the speeds involved and the proposed topology, [Jay] was able to build several working designs and was even able to overclock the memory. The takeaway is that for all the panic over DRAM signal timing on a board, some of it may be unnecessarily strict and buying modules with RAM already in place might be unnecessarily expensive. Of course, some of that is because none of these processors are running at very high-speeds or with overly complex and fast RAM.

The first half of the post is full of information like that, but devoid of any testing of the actual parts. When you get to the bottom half, you’ll see, though, that he uses ten different chips from vendors like Microchip, ST, NXP, Ti, Allwinner, and others. We were impressed with how much work was done, including benchmarks. The actual write up is impressive, too Each part has its own quirks, like the Allwinner part that can only address the first 16MB of flash. He even threw in a video, you can see below.

Truthfully, most of us won’t do this. We’ll just continue to buy boards. We have, however, seen people steal the SoC off a Pi and put it on their own board. If ARM SoC’s aren’t your thing, there have been x86 boards, too.

 

Upgrading a Classic Function Generator

อังคาร, 10/20/2020 - 15:00

If you need an oscilloscope, function generator, or other piece of kit for your electronics workbench, there are plenty of modern options. Dropping $4,000 for a modern oscilloscope is nice if you have the money, but if you’d rather put it to better use there are great options that don’t cost a fortune. There are some addons that can turn a smartphone into an oscilloscope but one of the best values out there are older pieces of equipment from the 80s that still work great. You can even upgrade them with some more modern features too, like [NFM] did with this vintage function generator.

This function generator is an HP3325A and it is several decades old, so some work was needed just to restore it to original working condition. The cooling fan and capacitors all needed to be replaced, as well as a few other odds and ends. From there [NFM] set about adding one of the two optional upgrades available for this device, the high voltage output. This allows the function generator to output 40 volts peak-to-peak at 40 milliamps. While he did have an original version from HP, he actually had a self-made design produced that matches the function of the original.

Even if you don’t have this specific function generator, this guide goes into great details about the functioning of older equipment like this. Most of the parts are replaceable and upgrades aren’t completely out of the question like some modern equipment, and with the right care and maintenance these pieces of equipment could last for decades longer.

Simplifying the Ruggedized Raspberry Pi Portable

อังคาร, 10/20/2020 - 12:00

Over the last year we’ve seen a wave of portable computer builds that center around the Raspberry Pi taking up residence inside a commercial heavy-duty storage case. It’s not hard to see why; whether you spring for the Pelican case or get a cheaper alternative, these water-tight cases are far stronger than anything you’re going to 3D print or otherwise cobble together in the home shop. Especially if you can avoid popping any holes in the side.

Inspired by these builds but looking to make it even easier and cheaper to roll your own version, [Dmitry] recently took the wraps off of what he calls the Militarish Pi. You don’t need a CNC to cut out any face plates or a 3D printer to create an internal framework for all your components. You could even do it without soldering anything, if you really wanted to. Short of just buying one of theses rigs pre-built from somebody, it’s hard to imagine it could get much easier than this.

Most of the effort involves cutting the PVC foam sheet that holds the Raspberry Pi, battery pack, and the driver board for the LCD in the bottom of the $15 USD case [Dmitry] managed to track down on AliExpress. The “carbon fiber” sticker he put on the PVC sheet won’t do much for the structural integrity of the build, but it sure looks nice. Of course if you have access to the appropriate tools, you could certainly cut the plate out of something stouter. As for the display, the nine inch LCD is perfectly sized to press fit into the lid.

Rounding out the build, [Dmitry] found a cheap Android phone case that included a tiny USB keyboard which plugs right into the Pi. He’s looking to add a BlackBerry trackball to the setup down the line, but in the meantime you can always tap on the screen. We especially like the large open area that he’s kept around the Raspberry Pi’s ports that allow you to easily hook up to the network or plug in a flash drive. It could also be a nice compartment to keep your RTL-SDR for some mobile radio work.

For those that don’t mind spending name-brand money and have access to a 3D printer, the Raspberry Pi Quick Kit by [Jay Doscher] is another great way to get yourself a rough and tumble Pi without reinventing the wheel.

Let KiCad and Python Make Your Coils

อังคาร, 10/20/2020 - 09:00

We like to pretend that our circuits are as perfect as our schematics. But in truth, PCB traces have unwanted resistance, capacitance, and inductance. On the other hand, that means you can use those traces to build components. For example, it isn’t uncommon to see a very small value current sense resistor be nothing more than a long PC board trace. Using PC layers for decoupling capacitance and creating precise transmission lines are other examples. [IndoorGeek] takes us through his process of creating coils on the PCB using KiCad. To help, he used a Python script that works out the circles, something KiCAD has trouble with.

The idea is simple. A coil of wire has inductance even if it is a flat copper trace on a PCB. In this case, the coils are more for the electromagnetic properties, but the same idea applies if you wanted to build tuned circuits. The project took inspiration from FlexAR, an open-source flexible PCB magnet.

KiCAD doesn’t like curved traces, but since the file format is open and text-based, it is easy to write scripts that can create shapes for you. [Joan Spark] provided the script. By the way, the goal for these magnets is to improve the mechanical 7-segment display we’ve looked at earlier.

It is really great to be able to work with text files and modify your PCB layouts; it leads to very handy tools. Of course, you can do the same kinds of tricks with gcode, but by that time, you’ve lost a lot of information.

Let KiCad and Python Make Your Coils

อังคาร, 10/20/2020 - 09:00

We like to pretend that our circuits are as perfect as our schematics. But in truth, PCB traces have unwanted resistance, capacitance, and inductance. On the other hand, that means you can use those traces to build components. For example, it isn’t uncommon to see a very small value current sense resistor be nothing more than a long PC board trace. Using PC layers for decoupling capacitance and creating precise transmission lines are other examples. [IndoorGeek] takes us through his process of creating coils on the PCB using KiCad. To help, he used a Python script that works out the circles, something KiCAD has trouble with.

The idea is simple. A coil of wire has inductance even if it is a flat copper trace on a PCB. In this case, the coils are more for the electromagnetic properties, but the same idea applies if you wanted to build tuned circuits. The project took inspiration from FlexAR, an open-source flexible PCB magnet.

KiCAD doesn’t like curved traces, but since the file format is open and text-based, it is easy to write scripts that can create shapes for you. [Joan Spark] provided the script. By the way, the goal for these magnets is to improve the mechanical 7-segment display we’ve looked at earlier.

It is really great to be able to work with text files and modify your PCB layouts; it leads to very handy tools. Of course, you can do the same kinds of tricks with gcode, but by that time, you’ve lost a lot of information.

Stomp Button, Receive Candy

อังคาร, 10/20/2020 - 06:00

If there’s any holiday that is worth adjusting for strange times, it’s gotta be Halloween. Are you inclined to leave a bowl of candy on the porch to avoid the doorbell? If so, this is the perfect year to finally figure out some sort of metering apparatus so that greedy preteens are less likely to steal your stash in one sweep. There’s still time to make something fun like [Brankly]’s automatic candy dispenser, which we think ought to stick around for many years to come. Video is posted after the break.

Underneath that skeleton’s jack-o-lantern head is the heart of this build — an orange 5-gallon bucket that matches it perfectly. Simply step on the giant lighted arcade button, and the equally giant NEMA-23 stepper motor moves a 3D-printed turntable inside the bucket with the help of an Arduino Nano. This moves the candy toward the 3D-printed ramp and out the mouth of the jack-o-lantern, where it lands in a bowl that lights up when it hits the bottom thanks to a relay and a second Nano.

[Brankly] made clever use of IR break-beam switches, which sit underneath the two square holes in the ramp. Once candy passes over one of them, the turntable stops and rotates backward to move the candy where it can’t be reached.

Frankly, we love that [Brankly] reused the sound effects module that came with the jack-o-lantern. This build is totally open, and [Brankly] is even giving away 40 PCBs if you want to make your own. For now, you can check out the code and start printing the STLs.

If time is tight, build a spooky slide that puts six feet between you and the trick or treaters.

Stomp Button, Receive Candy

อังคาร, 10/20/2020 - 06:00

If there’s any holiday that is worth adjusting for strange times, it’s gotta be Halloween. Are you inclined to leave a bowl of candy on the porch to avoid the doorbell? If so, this is the perfect year to finally figure out some sort of metering apparatus so that greedy preteens are less likely to steal your stash in one sweep. There’s still time to make something fun like [Brankly]’s automatic candy dispenser, which we think ought to stick around for many years to come. Video is posted after the break.

Underneath that skeleton’s jack-o-lantern head is the heart of this build — an orange 5-gallon bucket that matches it perfectly. Simply step on the giant lighted arcade button, and the equally giant NEMA-23 stepper motor moves a 3D-printed turntable inside the bucket with the help of an Arduino Nano. This moves the candy toward the 3D-printed ramp and out the mouth of the jack-o-lantern, where it lands in a bowl that lights up when it hits the bottom thanks to a relay and a second Nano.

[Brankly] made clever use of IR break-beam switches, which sit underneath the two square holes in the ramp. Once candy passes over one of them, the turntable stops and rotates backward to move the candy where it can’t be reached.

Frankly, we love that [Brankly] reused the sound effects module that came with the jack-o-lantern. This build is totally open, and [Brankly] is even giving away 40 PCBs if you want to make your own. For now, you can check out the code and start printing the STLs.

If time is tight, build a spooky slide that puts six feet between you and the trick or treaters.

PyBot is a 3D Printed SCARA Arm for the Masses

อังคาร, 10/20/2020 - 03:00

We’ve all seen videos of blisteringly fast SCARA arms working on assembly lines, and more than a few of us have fantasied about having that same kind of technology for the home shop. Unfortunately, while the prices for things like 3D printers and oscilloscopes have dropped lower than what many would have believed possible a decade ago, high-performance robotics are still too pricey for the home player.

Unless of course, you’re willing to build it yourself. The PyBot designed by [jjRobots] is an open source robotic arm that should be well within the means of the average hardware hacker. One could argue that this is a project made entirely possible by desktop 3D printing; as not only are most of the structural components printed, but most of the mechanical elements are common 3D printer parts. Smooth rods, linear bearings, lead screws, and NEMA 17 motors are all exceptionally cheap these days thanks to the innumerable 3D printer kits that make use of them.

A custom control board keeps the wiring tight.

Those who’ve researched similar projects might notice that the design of this arm has clearly been influenced by the Mostly Printed SCARA (MPSCARA). But while that robot was designed to carry an extruder and act as a 3D printer, [jjRobots] intends for the PyBot to be more of a general purpose platform. By default it features a simple gripper, but that can easily be changed out for whatever tool or gadget you have in mind.

In the base of the arm is a custom control board that combines an Arduino M0, an ESP8266, and a trio of stepper motor drivers. But if you wanted to build your own version from the parts bin, you could certainly wire up all the principle components manually. As the name implies, the PyBot is controlled by Python tools running on the computer, so it should be relatively easy to get this capable arm to do your bidding.

We’ve seen some impressive 3D printed robotic arms over the years, but the simplicity of the PyBot is particularly compelling. This looks like something that you could reasonably assemble and program over a weekend or two, and then put to work in your ad-hoc PPE factory.

Escape To An Alternate Reality Anywhere With Port-A-Vid

อังคาร, 10/20/2020 - 01:30

There was a time when only the most expensive televisions could boast crystal clear pixels on a wall-mountable thin screen. What used to be novelty from “High Definition Flat Screen Televisions are now just “TV” available everywhere. So as a change of pace from our modern pixel perfection, [Emily Velasco] built the Port-A-Vid as a relic from another timeline.

The centerpiece of any aesthetically focused video project is obviously the screen, and a CRT would be the first choice for a retro theme. Unfortunately, small CRTs have recently become scarce, and a real glass picture tube would not fit within the available space anyhow. Instead, we’re actually looking at a modern LCD sitting behind a big lens to give it an old school appearance.

The lens, harvested from a rear-projection TV, was chosen because it was a good size to replace the dial of a vacuum gauge. This project enclosure started life as a Snap-On Tools MT425 but had become just another piece of broken equipment at a salvage yard. The bottom section, formerly a storage bin for hoses and adapters, is now home to the battery and electronics. All original markings on the hinged storage lid were removed and converted to the Port-A-Vid control panel.

A single press of the big green button triggers a video to play, randomly chosen from a collection of content [Emily] curated to fit with the aesthetic. We may get a clip from an old educational film, or something shot with a composite video camera. If any computer graphics pop up, they will be primitive vector graphics. This is not the place to seek ultra high definition content.

As a final nod to common artifacts of electronics history, [Emily] wrote an user’s manual for the Port-A-Vid. Naturally it’s not a downloadable PDF, but a stack of paper stapled together. Each page written in the style of electronics manuals of yore, treated with the rough look of multiple generation photocopy rumpled with use.

If you have to ask “Why?” it is doubtful any explanation would suffice. This is a trait shared with many other eclectic projects from [Emily]. But if you are delighted by fantastical projects hailing from an imaginary past, [Emily] has also built an ASCII art cartridge for old parallel port printers.

Does Your Phone Need a RAM Drive?

อังคาร, 10/20/2020 - 00:01

Phones used to be phones. Then we got cordless phones which were part phone and part radio. Then we got cell phones. But with smartphones, we have a phone that is both a radio and a computer. Tiny battery operated computers are typically a bit anemic, but as technology marches forward, those tiny computers grew to the point that they outpace desktop machines from a few years ago. That means more and more phones are incorporating technology we used to reserve for desktop computers and servers. Case in point: Xiaomi now has a smartphone that sports a RAM drive. Is this really necessary?

While people like to say you can never be too rich or too thin, memory can never be too big or too fast. Unfortunately, that’s always been a zero-sum game. Fast memory tends to be lower-density while large capacity memory tends to be slower. The fastest common memory is static RAM, but that requires a lot of area on a chip per bit and also consumes a lot of power. That’s why most computers and devices use dynamic RAM for main storage. Since each bit is little more than a capacitor, the density is good and power requirements are reasonable. The downside? Internally, the memory needs a rewrite when read or periodically before the tiny capacitors discharge.

Although dynamic RAM density is high, flash memory still serves as the “disk drive” for most phones. It is dense, cheap, and — unlike RAM — holds data with no power. The downside is the interface to it is cumbersome and relatively slow despite new standards to improve throughput. There’s virtually no way the type of flash memory used in a typical phone will ever match the access speeds you can get with RAM.

So, are our phones held back by the speed of the flash? Are they calling out for a new paradigm that taps the speed of RAM whenever possible? Let’s unpack this issue.

Yes, But…

If your goal is speed then, one answer has always been to make a RAM disk. These were staples in the old days when you had very slow disk drives. Linux often mounts transient data using tmpfs which is effectively a RAM drive. A disk that refers to RAM instead of flash memory (or anything slower) is going to be super fast by comparison to a normal drive.

But does that really matter on these phones? I’m not saying you don’t want your phone to run fast, especially if you are trying to do something like gaming or augmented reality rendering. What I’m saying is this: modern operating systems don’t make such a major distinction between disk and memory. They can load frequently used data from disk in RAM caches or buffers and manage that quite well. So what advantage is there in storing stuff in RAM all the time? If you just copy a flash drive to RAM and then write it back before you shut down, that will certainly improve speed, but you will also waste a lot of time grabbing stuff you never need.

Implementation

According to reports, the DRAM in Xiaomi’s phone can reach up to 44GB/s compared to the flash memory’s 1.7GB/s reads and .75GB/s writes. Those are all theoretical maximums, of course, so take that with a grain of salt, but the ratio should be similar even with real-world measurements.

The argument is that (according to Xiaomi) games could install and load 40% to 60% faster. But this begs the question: How did the game get into RAM to start with? At first we thought the idea was to copy the entire flash to RAM, but that appears to not be the case. Instead, the concept is to load games directly into the RAM drive from the network and then mark them so the user can see that they will disappear on a reboot. The launcher will show a special icon on the home screen to warn you that the game is only temporary.

So it seems like unless your phone is never turned off, you are trading a few seconds of load time for repeatedly installing the game over the network. I don’t think that’s much of a use case. I’d rather have the device intelligently pin data in a cache. In other words, allow a bit on game files that tell them to stay in cache until there is simply no choice but to evict them and you’d have a better system. A comparatively fast load from flash memory once, followed by very fast startups on subsequent executions until the phone powers down. The difference is you won’t have to reinstall every time you reset the phone.

This is Not a Hardware RAM Drive

There have been hardware RAM drives, but that’s really a different animal. Software RAM drives that take part of main memory and make it look like a disk appears to have originated in the UK around 1980 in the form of Silicon Disk System for CP/M and, later MSDOS. Other computers of that era were known to support the technique including Apple, Commodore, and Atari, among others.

In 1984, IBM differentiated PCDOS from MSDOS by adding a RAM disk driver, something Microsoft would duplicate in 1986. However, all of these machines had relatively low amounts of memory and couldn’t spare much for general-purpose buffering. Allowing a human to determine that it made sense to keep a specific set of files in RAM was a better solution back then.

On the other hand, what the Xiaomi design does have one important feature. It is good press. We wouldn’t be talking about this phone if they hadn’t incorporated a RAM drive. I’m just not sure it matters much in real-life use.

We’ve seen RAM disks cache browser files that are not important to store across reboots and that usually works well. It is also a pretty common trick in Linux. Even then, the real advantage isn’t the faster memory as much as removing the need to write cached data to slow disks when it doesn’t need to persist anyway.

Exploring Animal Intelligence Hack Chat

จันทร์, 10/19/2020 - 23:00

Join us on Wednesday, October 21st at noon Pacific for the Exploring Animal Intelligence Hack Chat with Hans Forsberg!

From our lofty perch atop the food chain it’s easy to make the assumption that we humans are the last word in intelligence. A quick glance at social media or a chat with a random stranger at the store should be enough to convince you that human intelligence isn’t all it’s cracked up to be, or at least that it’s not evenly distributed. But regardless, we are pretty smart, thanks to those big, powerful brains stuffed into our skulls.

We’re far from the only smart species on the planet, though. Fellow primates and other mammals clearly have intelligence, and we’ve seen amazingly complex behaviors from animals in just about every taxonomic rank. But it’s the birds who probably stuff the most functionality into their limited neural hardware, with tool use, including the ability to make new tools, being common, along with long-distance navigation, superb binocular vision, and of course the ability to rapidly maneuver in three-dimensions while flying.

Hans Forsberg has taken an interest in avian intelligence lately, and to explore just what’s possible he devised a fiendishly clever system to train his local magpie flock to clean up his yard, which he calls “BirdBox”. We recently wrote up his initial training attempts, which honestly bear a strong resemblance to training a machine learning algorithm, which is probably no small coincidence since his professional background is with neural networks. He has several years of work into his birds, and he’ll stop by the Hack Chat to talk about what goes into leveraging animal intelligence, what we can learn about our systems from it, and where BirdBox goes next.

Our Hack Chats are live community events in the Hackaday.io Hack Chat group messaging. This week we’ll be sitting down on Wednesday, October 21 at 12:00 PM Pacific time. If time zones baffle you as much as us, we have a handy time zone converter.

Click that speech bubble to the right, and you’ll be taken directly to the Hack Chat group on Hackaday.io. You don’t have to wait until Wednesday; join whenever you want and you can see what the community is talking about.

Exploring Animal Intelligence Hack Chat

จันทร์, 10/19/2020 - 23:00

Join us on Wednesday, October 21st at noon Pacific for the Exploring Animal Intelligence Hack Chat with Hans Forsberg!

From our lofty perch atop the food chain it’s easy to make the assumption that we humans are the last word in intelligence. A quick glance at social media or a chat with a random stranger at the store should be enough to convince you that human intelligence isn’t all it’s cracked up to be, or at least that it’s not evenly distributed. But regardless, we are pretty smart, thanks to those big, powerful brains stuffed into our skulls.

We’re far from the only smart species on the planet, though. Fellow primates and other mammals clearly have intelligence, and we’ve seen amazingly complex behaviors from animals in just about every taxonomic rank. But it’s the birds who probably stuff the most functionality into their limited neural hardware, with tool use, including the ability to make new tools, being common, along with long-distance navigation, superb binocular vision, and of course the ability to rapidly maneuver in three-dimensions while flying.

Hans Forsberg has taken an interest in avian intelligence lately, and to explore just what’s possible he devised a fiendishly clever system to train his local magpie flock to clean up his yard, which he calls “BirdBox”. We recently wrote up his initial training attempts, which honestly bear a strong resemblance to training a machine learning algorithm, which is probably no small coincidence since his professional background is with neural networks. He has several years of work into his birds, and he’ll stop by the Hack Chat to talk about what goes into leveraging animal intelligence, what we can learn about our systems from it, and where BirdBox goes next.

Our Hack Chats are live community events in the Hackaday.io Hack Chat group messaging. This week we’ll be sitting down on Wednesday, October 21 at 12:00 PM Pacific time. If time zones baffle you as much as us, we have a handy time zone converter.

Click that speech bubble to the right, and you’ll be taken directly to the Hack Chat group on Hackaday.io. You don’t have to wait until Wednesday; join whenever you want and you can see what the community is talking about.

Motorized Magic Over HDMI

จันทร์, 10/19/2020 - 22:30

There is a certain warmth that seems to emanate from stereo receivers of the 70s, 80s, and 90s. Despite their large footprint and considerable heft, the soft glow of the indicator lights and solid kerthunk of switches provide a sense of coziness. When [Tom] recently swapped his receiver for a 1970s Pioneer SX-950, he found himself getting up from the couch to adjust the volume when watching TV far too often for his liking. Resolving to do something about it, he added some magic in the form of a motorized volume knob. One of the coolest tricks for stereos was to have a small motor attached to the volume knob so that it could turn the volume up or down via a remote.

The first obstacle came when [Tom] had to forgo the center tap on the potentiometer to get a motorized one. This meant the volume compensation feature would be disabled, which is but a small price to pay for convenience. After scouring the internet, he finally had the part in hand only to discover some troublesome capacitors in the way. The new pot had a rather large motor hanging off the back that the previous one didn’t have. Fortunately, there was a good bit of space between the PCB and the bottom of the chassis, so Tom was able to just flip the capacitors to the underside of the board and bend them on their sides.

The next problem to solve was how to change the volume remotely. IR was considered as well as optical cable control signals. What [Tom] did instead was to implement HDMI CEC (consumer electronics control). CEC was well documented and seemed simple to implement on an ATTINY4313 with the help of a half-H driver. The CEC protocol implemented by [Tom’s] TV seemed to be very sensitive to timing, so an external crystal was used to get more precise timing and additional handshaking was implemented to get the TV to accept the microcontroller as valid. A few fail-safes were added to make sure the motor didn’t burn out if something went wrong with the CEC protocol and a nice enclosure wrapped up the build quite nicely.

We’ve seen CEC implemented before on a PIC 18F87J50, but as a sender of CEC commands not a receiver. [Tom’s] code is available on GitHub and might prove useful if you’re looking to implement CEC on an AVR.

Thanks [Tom] for sending this one in!

Motorized Magic Over HDMI

จันทร์, 10/19/2020 - 22:30

There is a certain warmth that seems to emanate from stereo receivers of the 70s, 80s, and 90s. Despite their large footprint and considerable heft, the soft glow of the indicator lights and solid kerthunk of switches provide a sense of coziness. When [Tom] recently swapped his receiver for a 1970s Pioneer SX-950, he found himself getting up from the couch to adjust the volume when watching TV far too often for his liking. Resolving to do something about it, he added some magic in the form of a motorized volume knob. One of the coolest tricks for stereos was to have a small motor attached to the volume knob so that it could turn the volume up or down via a remote.

The first obstacle came when [Tom] had to forgo the center tap on the potentiometer to get a motorized one. This meant the volume compensation feature would be disabled, which is but a small price to pay for convenience. After scouring the internet, he finally had the part in hand only to discover some troublesome capacitors in the way. The new pot had a rather large motor hanging off the back that the previous one didn’t have. Fortunately, there was a good bit of space between the PCB and the bottom of the chassis, so Tom was able to just flip the capacitors to the underside of the board and bend them on their sides.

The next problem to solve was how to change the volume remotely. IR was considered as well as optical cable control signals. What [Tom] did instead was to implement HDMI CEC (consumer electronics control). CEC was well documented and seemed simple to implement on an ATTINY4313 with the help of a half-H driver. The CEC protocol implemented by [Tom’s] TV seemed to be very sensitive to timing, so an external crystal was used to get more precise timing and additional handshaking was implemented to get the TV to accept the microcontroller as valid. A few fail-safes were added to make sure the motor didn’t burn out if something went wrong with the CEC protocol and a nice enclosure wrapped up the build quite nicely.

We’ve seen CEC implemented before on a PIC 18F87J50, but as a sender of CEC commands not a receiver. [Tom’s] code is available on GitHub and might prove useful if you’re looking to implement CEC on an AVR.

Thanks [Tom] for sending this one in!

TTGO ESP32 Module with Multiple Personalities

จันทร์, 10/19/2020 - 22:00

Volos Projects educator [Danko Bertović] had a TTGO ESP32 board looking for a project, so he implemented a surprisingly functional weather station for such a small screen. Presumably that was too boring for him, so he decided to write a version of the classic Atari game Breakout instead. [Danko] prefers using the Arduino IDE for ESP32 projects, and has made the Breakout software available as an Arduino sketch. We hope the weather station sketch will be released soon, too. The TTGO is a small ESP32 board with an ST7789V 1.14 in (29 mm) TFT color display, available from your favorite Shenzhen market supplier. This platform is perfect for all kinds of niche applications. We’d love to hear how you are using, or plan to use, these modules in your projects.  

We wrote about one such project last summer, where a similar TTGO module was used to display 50-year broadcast delayed transcripts of the Apollo 11 mission. [Danko] is no stranger to Hackaday — he has made several Arduino-based calculator projects.  Perhaps the most remarkable being the circuit sculpture binary number calculator from last year, another project that morphed into a computer game (Pong).  

https://www.youtube.com/watch?v=N6V7ZJkhSbc