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The OS/2 Operating System Didn’t Die… It Went Underground

Hackaday - ศุกร์, 06/21/2019 - 09:00

One problem with building things using state-of-the-art techniques is that sometimes those that look like they will be “the next big thing” turn out to be dead ends. Next thing you know, that hot new part or piece of software is hard to get or unmaintained. This is especially true if you are building something with a long life span. A case in point is the New York City subway system. Back in the 1990s the transit authority decided to adopt IBM’s new OS/2 operating system. Why not? It was robust and we used to always say “no one ever got fired for buying IBM.”

There was one problem. OS/2 was completely eclipsed by other operating systems, notably Windows and — mostly — has sunk from the public view. [Andrew Egan’s] post covers just how the conversion to a card-based system pushed OS/2 underground all over the Big Apple, and it is an interesting read.

The choice of OS/2 might seem odd today. However, you have to remember the operating system landscape back then. Unix wasn’t very commercial, for the most part, and the commercial versions like Xenix and SCO were often encumbered with odd and changing licensing arrangements. MSDOS was hardly suitable for any sort of reliable system, with a patchwork of hacks to get more memory, and multitasking including early versions of Windows which were little more than shells over MSDOS.

We might have suggested QNX, as both operating systems were robust and used a microkernel architecture which had many advantages, especially when fighting hardware limitations.

It seems OS/2 isn’t just the subway system, either. Some old ATM machines still use it and there are probably some other hold outs. In 2006, IBM discontinued the operating system and sold off OS/2 support to Serenity Systems and later acquired by Arca Noae.

While OS/2 doesn’t get the same retrocomputer love as some other operating systems, it was actually ahead of its time. Its failure to take hold wasn’t so much about the technology as it was about business decisions and the market conditions of the day.

If you want a look at modern OS/2 emulation, that does exist. If you think OS/2 is the oldest tech running the subway system, you’d be wrong about that.

Building your own 555 timer IC

dangerous prototype - ศุกร์, 06/21/2019 - 06:08

The classic 555 timer on a breadboard:

Here, I will show how you can make your own version of the 555 timer using just NAND gates, opamps , a transistor and a few resistors! Now, you may think what is the purpose of building this when you can buy the IC at very cheap rates. The answer is, you learn electronics better, understand how the actual IC functions and improve your confidence in building electronic circuits.

More details on TheMagicSmoke blog.

Electric Wheelchair Makes A Great Base For A Big Robot

Hackaday - ศุกร์, 06/21/2019 - 06:00
Wiring into the joystick is a quick and easy way to hack in custom control to a wheelchair.

Building robots can be fun, and remains a popular pastime among many in the hacker and maker set. However the hardware side of things can be daunting. This is particularly the case for those attempting to build something on a larger scale. A great shortcut is to start with a robust mechanical platform from the outset – and using an electric wheelchair is a great way to do so.

[Nikita] started this project way back in 2009, after finding a broken electric wheelchair at a flea market. It was no longer in fit condition for use as a wheelchair, so [Nikita] was able to score it for the low price of just $50. That’s a great price for a package which includes a robust chassis, wheels, motors and the required controllers to drive it all. With the platform in hand, it was time to get hacking.

Thus far, [Nikita] has gone so far as to strip the wheelchair of all extraneous parts, leaving it as a motorized carriage. Radio control has been implemented with the help of an Arduino, and a couple of “eyes” have been added to give it a little personality. It can also still be driven with the original joystick, which has been relocated on the chassis. Future plans involve adding a level of autonomy to allow the ‘bot to navigate waypoints and recognise faces, both tasks which should be significantly easier with 2019 technology. We’re eager to see where it goes next; we’ve seen great applications of wheelchair hardware before, after all. Video after the break.

One Mix 3 Yoga benchmarks

Liliputing - ศุกร์, 06/21/2019 - 04:15

The One Mix 3 Yoga is a compact laptop with an 8.4 inch display and a 5 watt Intel Core m3-8100Y processor. It’s designed for portability more than bleeding-edge performance… but it’s actually a surprisingly capable laptop for most day-to day tasks. It has one of the best keyboards of any sub-10 inch laptop I’ve […]

The post One Mix 3 Yoga benchmarks appeared first on Liliputing.

The Feather “FAUXBERRY” Is Now A Real Thing

Hackaday - ศุกร์, 06/21/2019 - 03:00

Last month we featured an interesting project from Hackaday.io that was essentially trying to recreate the iconic Blackberry form factor for use with Adafruit’s line of Feather development boards. This would let you drop in modules for everything from LTE to packet radio, opening up a nearly limitless possibilities for handheld hacking. The only problem was, it didn’t actually exist yet.

But recently creator [arturo182] wrote in to tell us that not only had all the parts arrived, but that he’d completed assembly of the first prototype. He even put together a video about the current status of the device, which you can see after the break. The short version is: it works, and it looks fantastic.

For those who might not have seen this project the first time around, the front features a 2.6 inch 320×240 touch screen display, four general purpose buttons, a RGB NeoPixel LED for visual status display, a five way joystick, and what’s arguably the star of the show, a QWERTY keyboard originally designed for the Blackberry Q10. Around the back it has an SD card slot, a socket for the Feather module of your choice, and some handy GPIO expansion pads you can attach your own hardware onto.

[arturo182] says he’s looking at a couple cosmetic changes, but on the whole, everything works and he considers the PCB essentially done. He’ll soon be sending out a handful of test units to individuals who’ve expressed interest in helping him develop the project and then…well, he’s not really sure what’s going to happen then. Some kind of commercial release seems like the logical conclusion given the interest he’s already seen in the project, but he hasn’t quite worked out whether that will be a kit or as assembled devices.

Until then, anyone who’s looking for a pocket sized device that will let them bang out some Python with a physical keyboard will have to stick with their TI-83s.

Google scraps plans for future Pixel tablets

Liliputing - ศุกร์, 06/21/2019 - 02:38

If you’re in the market for a Google-branded Chrome OS device, right now you have two choices: the Google Pixelbook laptop or the Google Pixel Slate tablet. But according to a report from ComputerWorld, Google had been working on two new Chrome OS tablets… and according to that same report, Google has scrapped those plans […]

The post Google scraps plans for future Pixel tablets appeared first on Liliputing.

Finally, An Open Source Multimeter

Hackaday - ศุกร์, 06/21/2019 - 01:30

For his Hackaday Prize entry, [Martin] is building an Open Source Multimeter that can measure voltage, current, and power. It’s an amazing build, and you too can build one yourself.

The features for this multimeter consist of voltage mode with a range of +/-6V and +/-60V. There’s a current mode, basically the same as voltage, with a range of +/-60 mA and +/-500mA. Unlike our bright yellow Fluke, there’s also a power mode that measures voltage and current at the same time, with all four combinations of ranges available. There’s a continuity test that sounds a buzzer when the resistance is below 50 Ω, and a component test mode that measures resistors, caps, and diodes. There’s a fully isolated USB interface capable of receiving commands and transmitting data, a real-time clock, and in the future there might be frequency measurement.

This build is based on the STM32F103 microcontroller, uses an old Nokia phone screen, and unlike so many other multimeters, this thing is small. It’s very small. More than small enough to fit in your pocket and forget about it, unlike nearly every other multimeter available. There’s one thing about multimeters, and it’s that the best multimeter is the one that you have in your hands when you need it, and this one certainly fits the bill.

The entire project is being written up on hackaday.io, there’s a GitHub repo for all the hardware and software, and there’s also a video demo covering all the features (available below). This is a stand-out project, and something we desperately want to get our hands on.

The HackadayPrize2019 is Sponsored by:

Daily Deals (6-20-2019)

Liliputing - ศุกร์, 06/21/2019 - 00:56

Amazon is running a 1-day sale on Logitech PC accessories including mice, keyboards, webcams, headphones, game controllers, and speakers. I’ve included some deals that stand out below, but make sure to check out the sale page for a full listing. Here are some of the day’s best deals. PC and mobile accessories Select Logitech PC […]

The post Daily Deals (6-20-2019) appeared first on Liliputing.

Spy Tech: Tiny Spy Plane becomes Cold War Prize

Hackaday - ศุกร์, 06/21/2019 - 00:00

What looks like something famous, is much smaller, and is embroiled in a web of cold war cloak-and-dagger intrigue? It sounds like the answer could be Mini-Me from the Austin Powers movies, but we were actually thinking of the D-21 supersonic spy drone. Never heard of it? It didn’t have a very long service life, but it was a tiny little unmanned SR-71 and is part of a spy story that would fit right in with James Bond, if not Austin Powers.

The little plane had a wingspan of only 19 feet — compared to the SR-71’s 56 foot span — and was 42 feet long. It could fly at about Mach 3.3 at 95,000 feet and had a range of around 3,500 miles. It shared many characteristics with its big brother including the use of titanium and a design to present a low RADAR cross-section.

The Spy Who Photographed Me

With today’s global economy and increased international cooperation, it is hard to remember just how tense the late 1960s were. Governments wanted to see what other governments were up to. Satellite technology would eventually fill that role, but even though spy satellites first appeared in 1959, they used film that had to be retrieved by an airplane as it fell from the sky and then processed. Not exactly real time. More effective satellites would have to wait for better imaging technology — see the video below for just how bad those old satellite images were. That left spy planes to do the bulk of the work.

The problem with spy planes is they can get shot down. This happened famously when Gary Powers was shot down while flying a U-2 over Russia. The best answer to that is getting higher than your adversary can shoot — and that’s the basic genesis of the famous SR-71 by Lockheed. However, Lockheed proposed several answers, including the D-21. This spy plane had no crew, so while having it shot down — as unlikely as that was — would have been embarrassing, it wouldn’t be as bad as having a pilot on the news confessing to espionage.

The Little Plane that Couldn’t

There were 38 D-21’s built. Lockheed skunkworks was responsible, so it is not surprising the craft looks a bit like a tiny SR-71 with swept back delta wings. In fact, the original plan was to launch the plane from a modified SR-71. The plane would streak over its target taking pictures, eject a film bucket — much like a satellite does — and then self destruct. A plane would either snag the film bucket or it could be recovered at sea by a ship.

In 1962, a full-scale mockup was ready, known as the Q-12. The CIA wasn’t very interested, but the air force wanted it not only as a spy plane but as a cruise missile. The 1964 initial tests carrying the thing aloft on a mothership were not promising. At first, the D-21 had aerodynamic covers put on its engines to reduce drag. They found there was no safe way to remove them at Mach 3, so they had to stop flying with the covers.

By 1966 they were trying to actually test launch the D-21. Flying at over Mach 3 at 90,000 feet, the plane was plagued with issues. A hydraulic pump failure took one plane. Another flight was successful, but the film bucket failed to eject.

It was the fourth launch that would convince Lockheed to stop launching from a modified SR-71. The video below shows disturbing footage of the result. The previous launches had the host aircraft make a loop to help separate the two craft. This time they tried from a straight and level flight path. The D-21 had an engine failure which caused it to strike the tail of the SR-71 host. The two crew ejected over the ocean, and the launch control officer, Ray Torrick, drowned before recovery.

The B-52s

This caused two major changes to the D-21 program. First, a solid rocket booster would push the plane off its carrier. Second, the carrier was to be a Boeing B-52 bomber. The drone would now attach from the top with the bottom carrying the rocket booster which was actually larger than the D-21 (now known as the D-21B).

These changes didn’t do much to change the drone’s luck. The first attempted launch in 1967 saw the drone fall off the carrier early due to a stripped nut. It would take five more attempts before there was a completely successful flight. Of the next five flights, two would be unsuccessful.


By late 1969, the D-21 started its brief operational life. The mission: spy on the Chinese nuclear test site at Lop Nor. The plan was the planes would launch from Guam, fly over Lop Nor, turn around, and fly back over the ocean to deliver the film and self destruct.

The first mission failed to turn and crashed in the Soviet Union. The second mission worked better but had a fault when trying to eject its film. While the third time was the charm for the D-21, the crew retrieving the film couldn’t say as much. The plane that should have snagged the film bucket in mid-air missed. The Navy destroyer sent to retrieve it in the ocean instead ran it over and the film sunk to the bottom of the ocean. The fourth, and mercifully final, flight crashed over China where it languished for years in a junkyard before going on exhibit at the China Aviation Museum.

By July 1971, the program was done. Satellite imaging was getting better and Nixon had been to China. Of the 38 built, 17 remain in storage at the Air Force boneyard. However, the really interesting thing is what happened to that very first lost D-21.

The Sincerest Form of Flattery

That first operational flight crashed in what might have been the worst possible place from the United State’s perspective: the Soviet Union. As you might expect, the Soviets gathered up the wreckage and studied it.

The Tupolev Experimental Design Bureau opened project Voron to produce an imitation of the D21. It never flew, but the work provided valuable insights on materials and techniques for supersonic aircraft and missiles. However, by the time Voron would be something to build, the Soviets, too, were betting on spy satellites.

Spy vs Spy

It is amazing how much expense and trouble governments will go through to spy on each other. Of course, all of this was highly classified in its own time. Corona — the first spy satellites — were classified until 1995. Many of the D-21 records were classified until late last year. The last link on that page has some great pictures that are poorly scanned. There are other interesting tidbits including directions on how to deal with public sightings or a crash that is visible to the public.

We always find it interesting to catch up on recently declassified material, especially when it is high tech. Did you know the US stole a Soviet moon lander? But don’t worry, the Russians stole one from the US, too.

Photo credits:

All photos are public domain except for:

D-21 wreck in Chinese Aviation Museum by [N Ezov], CC-BY-SA-4.0.

Automated Dice Tester Uses Machine Vision to Ensure a Fair Game

Hackaday - พฤ, 06/20/2019 - 22:30

People take their tabletop games very, very seriously. [Andrew Lauritzen], though, has gone far above and beyond in pursuit of a fair game. The game in question is Star War: X-Wing, a strategy wargame where miniature pieces are moved according to rolls of the dice. [Andrew] suspected that commercially available dice were skewing the game, and the automated machine-vision dice tester shown in the video after the break was the result.

The rig is a very clever design that maximizes the data set with as little motion as possible. The test chamber is a box with clear ends that can be flipped end-for-end by a motor; walls separate the chamber into four channels to test multiple dice on each throw, and baffles within the channels assure randomization. A webcam is positioned below the chamber to take a snapshot of each “throw”, which is then analyzed in OpenCV. This scheme has the unfortunate effect of looking at the dice from the table’s perspective, but [Andrew] dealt with that in true hacker fashion: he ignored it since it didn’t impact the statistics he was interested in.

And speaking of statistics, he generated a LOT of them. The 62-page report of results from his study is an impressive piece of work, which basically concludes that the dice aren’t fair due to manufacturing variability, and that players could use this fact to cheat. He recommends pooled sets of dice to eliminate advantages during competitive play. 

This isn’t the first automated dice roller we’ve seen around these parts. There was the tweeting dice-bot, the Dice-O-Matic, and all manner of electronic dice throwers. This one goes the extra mile to keep things fair, and we appreciate that.

[gadwag] tipped us off to this one. Thanks!

Vivo’s 120W fast charger refuels a 4,000 battery in 13 minutes, might not burn down your house

Liliputing - พฤ, 06/20/2019 - 22:28

The fast charging wars continue. A few months after Xiaomi unveiled new technology that can charge a 4,000 mAh battery in just 17 minutes, rival Chinese phone maker Vivo says it can do the same thing in 13 minutes. That would make the company’s 120W Super FlashCharge the fastest technology around for quickly refueling batteries […]

The post Vivo’s 120W fast charger refuels a 4,000 battery in 13 minutes, might not burn down your house appeared first on Liliputing.

Electric Cars Sound Off, Starting July 1st

Hackaday - พฤ, 06/20/2019 - 21:00

By and large, automakers have spent much of the last century trying to make cars quieter and more comfortable. Noise from vehicles can be disruptive and just generally annoying, so it makes sense to minimise it where possible.

However, the noise from the average motor vehicle can serve a useful purpose. A running engine acts as an auditory warning to those nearby. This is particularly useful to help people avoid walking in front of moving vehicles, and is especially important for the visually impaired.

Electric vehicles, with their near-silent powertrains, have put this in jeopardy. Thus, from July 1st, 2019, the European Union will enforce regulations on the installation of noise-making devices on new electric and hybrid vehicles. They are referred to as the “Acoustic Vehicle Alert System”, and it’s been a hot area of development for some time now.

They’re making the cars louder now?

It might seem like a waste of effort and energy, but safety is a serious businses. Monash University reported in 2018 that 35% of vision impaired persons surveyed had experienced collisions or near-miss incidents with electric or hybrid vehicles. This promises to be a growing problem as the take-up of electric cars increases, so it’s no surprise that laws are coming in to effect to deal with the problem.

The European Union ratified its guidelines for Acoustic Vehicle Alerting Systems, or AVAS, way back in 2014, giving automakers plenty of time to comply with the directive. The intention is for electric and hybrid vehicles to emit artificially generated noise when travelling at low speeds, for the purpose of warning pedestrians and other vulnerable road users of the vehicle’s presence and activity.

While there is no strict specification of the sound to be made, the intention is that a vehicle should make a sound similar in nature to that of its gasoline-powered equivalent. This is in order to make the system intuitive for all road users. It would obviously be confusing and dangerous if large trucks sounded like small hatchbacks, and vice versa, so cars are considered by category and weight class.

To warn pedestrians, synthesized sounds are created that respond to vehicle behaviour.

The official requirements make for interesting reading. The sounds emitted are intended to vary in volume and pitch, depending on vehicle behaviour. There are minimum requirements, enforced by a test regime, to ensure the systems meet the spirit and the letter of the regulations. The minimum sound level is 56 dB(A) as measured in the test, and the AVAS must be active at speeds below 20km/h. Above that, road noise from the tyres is considered to be loud enough to warn pedestrians. The AVAS is also expected to make sound when the vehicle reverses. Sound must be continuous, and the maximum sound level is restricted to 75 dB(A) – around about the same as a toilet flushing, or an average gasoline-fueled car. Outside of this, and some specifications on mandatory minimum frequency sweeps with relation to speed, automakers have plenty of scope to personalise the sound to suit their brand.

What’s It Like, Then?

It’s not the first time automakers have intentionally made cars louder with synthesized sound; sports models have been doing it for a while now, much to the chagrin of diehard automotive purists. However, rather than directly replicating the sound of an internal combustion engine, car companies have employed crack teams to develop unique and compelling sounds to usher in the age of electrification.

Jaguar’s first electric vehicle, the I-Pace, launched in 2018. Significant resources were spent on AVAS development.

As you’d expect, most have gone with a very science fiction, spaceship-like sound. Some have been working on the technology longer than others; there’s video of an early Audi e-tron project from way back in 2011, 3 years before the EU decided to enact the AVAS legislation. Nissan have had their Leaf on the road making sounds for almost that long, while Jaguar launched their system with their all-electric I-Pace. Most automakers have stuck to a fairly futuristic theme, while putting their own twist on the sound.

Would you trust these guys to build you an acoustic warning system? Me neither.

Electric trailblazers Tesla are yet to reveal the noise their vehicles will make after the July deadline, and Volkswagen are similarly playing their cards close to their chest.

We’d be surprised if they go with anything too outlandish. The fact that it has taken this long for regulations to come in is a testament to the inertia of goverments and big business interests. Still, it’s been a topic of some thought for a while now, given that electric vehicle noise was a key plot component of a mindblowing Kevin James film from 8 years ago. If the EU had moved quicker by about a decade, we could have avoided The Dilemma (2011) entirely.

Is It A Big Deal?

Fundamentally, it’s a useful technology to keep pedestrians safe, and as the technology is only active at low speed, it’s unlikely to bother anyone too much on a day-to-day basis. Unlike your straight-piped Fox body project car, your AVAS isn’t going to wake the neighbours or send the neighbourhood cats scrambling up a tree. With the legislation being largely done and dusted 5 years ago, and with the US set to enforce similar regulations in the next few years, it’s pretty much a closed matter. Expect there to be minor regional differences in requirements, similar to the variances in indicators and automotive lighting the world over. Overall though, the average punter will barely notice the technology – other than noting that these new whizz-bang cars do sound awful fancy, don’t they? Change, it is ever thus!

Seeing Transistors Switch In Infrared

Hackaday - พฤ, 06/20/2019 - 18:00

In the hacker and DIY community, there are people who have exceptional knowledge and fantastic tools. These people are able to do what others could only dream about, and that others can only browse eBay looking for that one tool they need to do the job. One of these such people is [John McMaster]. He is the resident expert on looking inside integrated circuits. He drops acid on a chip, and he can tell you exactly how it works on the inside.

At the hardwear.io conference, [John] shared one of his techniques for reverse-engineering intgrated circuits. He’s doing this by simply looking at the transistors, and looking at the light they give off. He’s also looking at the wrong side of the die.

The technique [John] is using is properly called backside analysis, or looking at the infrared emissions of electron recombinations. This happens at the junction of every transistor when it’s active, and these photons are emitted at the bandgap of silicon, or about 1088 nm, far into the infrared. This sort of thing has been done before by [nedos] at CCC in 2013, but rarely have we seen a deep dive into the tools and techniques needed to look at the reverse side of an IC and see the photons coming off.

An IC, seen in infrared

There are several tools [John] used for this work, and he actually did a good comparison of different camera technologies used to image infrared photon emissions from integrated circuits. InGaAs cameras are expensive, but they offer high sensitivity. New back-illuminated CMOS cameras and cooled CCDs normally reserved for astrophotography were also tested, and as always, you get what you pay for; the most expensive cameras worked best, but there were ways you could make the cheap ones work.

As with any camera work, preparing the lighting is of utmost importance. This includes an IR pass filter, and using only LED lighting in the lab with no sunlight, incandescent, or halogen light bulbs in the room — you don’t want any IR, after all. A NIR objective in the microscope was sourced from eBay, for about 1/10th the normal cost, because the objective had a small, insignificant scratch. Using this NIR objective made the image twice as bright as any other method. You can successfully image a chip with this, and [John] tested the setup on a resistor inside a CD4050 chip; the resistor glowed a slight purple, the color you would expect with infrared sensors. But can it work with I/O levels in a more modern chip? Also, yes. It needs some Photoshop to process, and stretching the 12-bit or 16-bit color space into an 8-bit color space, but it does work.

Finally, the supreme achievement of doing backside IR analysis. Is that possible with even this minimal setup? This requires some preparation; the silicon substrate in an IC is transparent in IR, but there is attenuation and this is especially important when the substrate is 300 um thick. This needs to be shaved down to about 25 um thick, which surprisingly is best done with fine sandpaper and a finger.

While few IR emissions were observed via backside emissions, the original plan wasn’t to completely analyze the chip, but merely to do some floor planning. For this, it worked. It’s a remarkable amount of work to see the inside of a silicon chip.

Steamed Hams Localized Entirely Within A Printed Circuit Board

Hackaday - พฤ, 06/20/2019 - 15:00

Maybe you’ve heard of a TV show called The Simpsons. Steamed Hams make a one-gag appearance in an unforgettable luncheon where Principal Skinner poker-faces his way out of a disaster with Superintendent Chalmers. Meanwhile, over on imgur, [Agumander] has put a black and white screencap from Steamed Hams in a printed circuit board.

The memory for this chip is an AT28C64, a 64 kilobit or 8 kilobyte steamed RAM. You call it a steamed RAM despite the fact that it is obviously a ROM. There is no microcontroller on this board or really anything resembling programmable logic. Everything is just logic chips. This board displays a 256×256 1 bit per pixel image over composite video. The sync is generated with the help of a 14MHz crystal and some circuitry taken from the original PONG board. Other than that, it’s just a bunch of NANDs and ORs that roll through the address space of the ROM and spit values out over a composite video port.

The build began by breadboarding everything save for a nifty solderless breadboard power adapter. Three ROM chips were programmed with different images — a cat, something to do with vaporwave, and some guy that looks like the poster from Eraserhead. Everything worked on the breadboard — yes, even at 14 MHz — so the build moved on to a printed circuit board.

The result is fantastic, and should work well on anything with a composite video port. We’re awarding bonus points for putting a socket on the ROM, simply so [Agumander] can change the image without whipping out the desoldering braid. If you need a refresher on Steamed Hams, it’s from the 7th season Simpsons episode ’22 Short Films About Springfield’.

A Baby Named DJ

Hackaday - พฤ, 06/20/2019 - 12:30

Some of us are guilty of picking up questionable hardware from garage sales, fleamarkets, and well-meaning relatives. There is a balance between turning down a good investment and hoarding, and if we figure out how to tell the difference you will be the first to know. [Clem Mayer] may start on the side of unwise acquisition, but he pushes a broken fetal detector into the realm of awesome by converting it to an analog synthesizer, born to headline at an Eastern European dance party.

He starts with a basic teardown, and we get to see how old hardware was serviceable with only two standard screws. It is a good thing too, because the nickel-cadmium batteries are older than some of you and they are in need of replacement. New nickel-metal hydride batteries got it up and running but [Clem] does not have a baby bump so its functionality turned to Pink Floyd era synthesizer circuit bending. Circuit bending involves modifying a circuit for sound it was not intended to make.

The exact circuit is never revealed because it is made and remade many times on the bench, but the gist is to start with the stock signal and treat it as a drum machine effect where 555 timers provide clock signals and sound synthesis, from there counters and switches establish a pattern, then some filtering, back to the timers and counters for chopping, and finally to an amplifier and out a speaker. Did you notice the lack of a microcontroller? We bet you did.

Even though this type of circuit hails from decades past, there is a message about using readily-available hardware. We learn that even if we cannot find an old fetal detector, the modern components and techniques will serve us the next time a “vintage” bit of hardware lands in the lab.

Once the circuit is in action we are treated to a couple of songs composed by our hacker, called Binary Dreams at 11:40 and Mental Spaghetti at 12:11. He is hardly the only composer in the neighborhood, check out Daphne Oram who wrote the book on electronic music and a guy who reads the book a little differently.

Via Element14 projects (membership required).

Abusing A CPU’s Adders To Optimize Bit Counting

Hackaday - พฤ, 06/20/2019 - 09:00

If you like nitpicking around C code and generated assembly language — and we’ll admit that we do — you shouldn’t miss [Scaramanga’s] analysis of what’s known as Kernighan’s trick. If you haven’t heard of the trick, it’s a pretty efficient way of counting bits.

Like the Wheatstone bridge and a lot of other things, the Kernighan trick is misnamed. Brian Kernighan made it famous, but it was actually first published in 1960 and again in 1964 before he wrote about it in 1988. The naive way to count bits would be to scan through each bit position noting how many one bits you encounter, but the problem is, that takes a loop for each bit. A 64-bit word, then, takes 64 loops no matter what it contains. You can do slightly better by removing each bit you find and stopping when the word goes to zero, but that still could take 64 cycles if the last bit you test is set.

Using the trick, you make the observation that X & (X-1) will always clear the least significant bit of a word. Try a few examples:

X X-1 X&(X-1) 0001 0000 0000 0010 0001 0000 0011 0010 0010 1010 1001 1000 1100 1011 1000 1111 1110 1110

You can probably see where this is going. By computing X&(X-1) you clear a bit on each loop iteration and you only have to go through the number of bits that are actually set.

This kind of thing is a common enough type of interview question although as [Scaramanga] points out, compilers will probably optimize this to use specific CPU operations and get even better performance. The POPCNT instruction on the x86 architecture, for example, will do it all in one instruction. He also has a detailed explanation of exactly why this works the way it does.

Of course, most software doesn’t need to run so fast that it is worth using obscure tricks. But sometimes it makes sense. It is also a nice test of logic and problem solving in an interview situation.

If you like this sort of thing, be sure to check out [Sean Anderson’s] extensive list of bit hacks. It shows several different ways to count bits and do other common and uncommon tasks with different tradeoffs. For example, you could dedicate a 256-entry lookup table and do the whole thing with one loop per byte with great speed but bad memory utilization. Always a trade-off.

There are lots of ways to play with bits, especially in C. Or you can use tools to chop things up if you just want to analyze them.

Hams Gone Wild: Amateur Radio Field Day 2019

Hackaday - พฤ, 06/20/2019 - 06:00

Of all the images that amateur radio conjures up, the great outdoors doesn’t usually figure heavily. People seem to think hams sit in a dark room at a desk heavy with radio gear, banging out Morse code into late into the night and heedless of the world outside the window. All of which sort of sounds like hard-core gaming, really.

And while that image certainly applies in a lot of cases, hams do like to get out and about at least once a year. That day is upon us with the 2019 Amateur Radio Field Day. Hams across North America reserve the fourth full weekend of each June to tear themselves out of their shacks and get into the world to set up operations in some kind of public venue, generally a park or other green space. Part cookout, part community outreach, and part slumber party – it lasts all weekend and goes around the clock – hams use field day as a chance to show the general public where amateur radio really shines: real-time worldwide communications under austere conditions.

It’s also a chance to get folks excited about getting their license, with many Field Day locations hosting “Get on the Air” stations so that unlicensed folks can try making a contact under the supervision of a licensed operator. Licensed but underequipped hams also get the chance to spin the knobs on someone else’s gear, and maybe line up that first rig purchase. And there are plenty of opportunities to learn about new modes as well, such as FT8 and WSPR. As an example your scribe is looking for some guidance on getting started with APRS, the automated packet reporting system that’s used for things like high-altitude balloon tracking.

If you have any interest at all in learning how to properly operate radio equipment, you owe it to yourself to track down the nearest Field Day location and stop by. The American Radio Relay League (ARRL) has a ton of Field Day information, from a map to locate the 1500 Field Day sites to rules for the contests that will be run that weekend to guides for setting up and operating an effective Field Day setup. There will be 40,000 hams out there this year, and they’d all be thrilled if you drop by and ask a few questions.

Microsoft’s Chromium-based Edge browser preview now available for Windows 7 and up

Liliputing - พฤ, 06/20/2019 - 05:20

Microsoft is designing a new version of its Edge web browser based on Google’s Chromium. Two months ago Microsoft released the first preview of the new browser, but it was only available for Windows 10 at the time. Now you can download Microsoft Edge preview builds and run them on Windows 7, Windows 8, or […]

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First look: One Mix 3 Yoga mini laptop with 8.4 inch display, Intel Amber Lake

Liliputing - พฤ, 06/20/2019 - 04:52

This is shaping up to be a busy year for mini-laptops, with new models coming from GPD, Chuwi, and One Netbook. The One Mix 3 Yoga is the first out of the gate, and it’s a little laptop with an 8.4 inch touchscreen display, a 360-degree hinge, and Intel Amber Lake processor. It went up […]

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Tomorrow Night: HDDG 40, Mechanical And Electronic Ephemera

Hackaday - พฤ, 06/20/2019 - 03:00

For the last several years, we’ve hosted a series of meetups for the Bay Area. This week is no different and we’re pleased to announce the fortieth Hardware Developers Didactic Galactic. It’s this Thursday, June 20th, in downtown San Francisco.

The Hardware Developers Didactic Galactic is our monthly IRL meetup, where we ask hardware developers what makes their thing tick. We’ve done dozens of these things, and for those of you in Internet-land, all the talks are available online. Even if you’re not in the Bay Area, all the talks are live streamed. Yes, you too can participate in the event, even if you’re not going to physically attend! It’s an amazing technology called ‘the Internet’ that combines real life with virtual being! It’s like [William Gibson] created some sort of virtual/hyperspace interface.

For this month’s talks, we’ll be joined by Embedded Ninja Shaun Meehan. Shaun has previously given talks that answer the question, what happens when the majority of your work blows up on the Antares space accident? You turn around and get some of your second string units on the next SpaceX launch (9 days later)! Shaun will be talking about his two 300kg robotic arms, FRED & LEFTY, and the project of replacing their 1987 era controllers. This talk includes high power electronics, FPGAs, fixed point algorithms, galvanic isolation, transistor matching, splitting transistors in half, strange position sensors, homemade 3-phase 480 in a garage, and freight LTL shipping.

The live stream for the talks will be available here. Of course, if you can make it to downtown San Francisco (a few blocks south of the Powell Muni/BART stop) we’d be happy to see you. It all goes down Thursday, July 20th, at 6:30 PM.

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