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Hacking Shelters and Swimming Pools

Hackaday - 5 hours 17 minก่อน

How would you survive in a war-torn country, where bombs could potentially fall from the sky with only very short notice? And what if the bomb in question were The Bomb — a nuclear weapon? This concern is thankfully distant for most of us, but it wasn’t always so. Only 75 years ago, bombs were raining down on England, and until much more recently the threat of global thermonuclear war was encouraging school kids to “duck and cover”. How do you protect people in these situations?

The answers, naturally, depend on the conditions at hand. In Britain before the war, money was scarce and many houses didn’t have basements or yards that were large enough to build a family-sized bomb shelter in, and they had to improvise. In Cold War America, building bomb shelters ended up as a boon for the swimming pool construction industry. In both cases, bomb shelters proved to be a test of engineering ingenuity and DIY gumption, attempting to save lives in the face of difficult-to-quantify danger from above.

Anderson and Morrison

If you are a well-funded construction company making a bunker for some General or politicians, setting up a bomb shelter isn’t that hard. Find some land, buy it, excavate, pour concrete, and spend what you want on things like air conditioning and furniture. The equation is different, though, if you need to make lots of shelters to fit in peoples’ modest yards using simple materials. Homes in the UK rarely have cellars or basements, and even so, basements became death traps in the aggressive bombing during the war.

Just before the UK joined WWII, Lord Privy Seal Anderson was in charge of preparing for air attack. He turned to two men, William Patterson and Karl Kerrison, to come up with a practical solution. The so-called Anderson shelter was little more than some corrugated steel panels. Of the fourteen panels, some were curved and some were straight. The shelters were very effective because they’d be covered with dirt or sandbags.

You can see they weren’t spacious. An Anderson was about six feet long, a bit over six feet high and about four and a half feet wide. If you didn’t make much money, you got one for free. Most people had to pay a nominal sum for one, though.

What you did with the inside of your shelter was up to you. As you might expect, there was quite a bit of variation.

One common problem with the shelters, though, was that they were cold. No shelter will protect a family that won’t go in it, so the British government had some advice about staying warm. Ultimately, though, they developed the Morrison shelter. Although only a few of the three million or so Anderson shelters went into homes with sandbags, the Morrison shelter was strictly an indoor affair.

The Morrison shelter looked like a table with a crawl space underneath. In fact, it could be used as a table. John Baker, the designer, knew it would be impossible to shield against a direct hit under his design constraints, so he focused on mitigating common bomb-related deaths, such as roof collapses. The shelter took its name from the Minister of Home Security, Herbert Morrison and — honestly — reminds us of a rabbit cage.

There were other shelter types, too, as well as people taking refuge in tunnels such as the Underground. Some people were saved, but there were many cases of people in shelters dying.

Across the Channel

The Germans learned that basements — a common feature in German homes — were not good places to wait out a bombing. So they built Hochbunkers — high rise bunkers completely above ground. These structures had very thick walls up to 1.5 m thick.

These shelters might seem unlikely, but they were pretty successful. Attempts to destroy them on purpose after the war proved difficult, so many of them are still around being used for schools, offices, and storage space. The video below shows a Hochbunker in Munich that now serves as an apartment complex.

Duck and Cover in Your New Pool

If you think your Anderson shelter won’t survive a direct hit from a conventional bomb, imagine a direct hit from a nuclear one. However, during the Cold War, people were building fallout shelters. The idea is that you might survive a moderately nearby nuclear blast only to be killed by fallout up to a few weeks later. However, if you had a place to hang out for a few weeks, you might survive to rebuild civilization or destroy post-apocalyptic zombies or whatever.

It was so easy to build that even old Walt could do it — at least according to the concrete masonry industry in the film below. If you had a basement it was pretty easy to refit it and you could use the space as a bizarre guest room or a darkroom as the excited actors in that little drama continually point out.

If you want to read the books that Walt shows, there are quite a few copies of the Family Fallout Shelter guide floating around. We couldn’t find “Mr. Atom and his Sinister Blanket”, other than a few pictures from an auction and as a brief part of a historical video on the National Concrete Masonry Association (look around the 9:50 mark). We actually talked about Walt a few years ago.

In America as in Britain, in many parts of the country people don’t have basements. In that case, you need to dig out a fallout shelter, and that’s too much work for most people. The answer? Hire someone with an excavator to do it, so pool contractors got in on the act. Vice-versa, in other areas, contractors who set up to do excavations to capitalize on the fallout shelter craze turned to building pools once the shelter business started — no pun intended — drying up.

Of course, most people didn’t build their own shelters: they were going to go to the local Civil Defense shelter. According to experts, that wouldn’t have worked if there had been a real war. It is hard to remember just how afraid everyone was over a sudden and massive nuclear strike during the cold war. We had CONELRAD and bright yellow Geiger counters. Some of the things were maybe to make you feel better even if they weren’t totally effective.

Today we have preppers building bunkers against the upcoming collapse of society, which isn’t too different. Maybe our grandkids will be building bunkers against the alien hoard that is bound to show up at any time now. Of course, if you have a lot of spare cash, you could score a pretty sweet five-bedroom bunker with all the amenities.

Photo credit: Hochbunker photo Creative Commons SA 3.0 by [Stefan Kühn]

Daily Deals (7-18-2019)

Liliputing - พฤ, 07/18/2019 - 23:41

Another week, another free PC game from the Epic Games Store. This time it’s Limbo, a popular puzzle-platformer released in 2010. While you can typically pick up this game for $10 or less, you know what’s an even better price? Free. Here’s a roundup of some of the day’s best deals. Digital downloads and streaming […]

The post Daily Deals (7-18-2019) appeared first on Liliputing.

Project Egress: The Hinges

Hackaday - พฤ, 07/18/2019 - 22:30

A door’s hinges are arguably its most important pieces. After all, a door without hinges is just, well, a wall. Or a bulkhead, if we’re talking about a hingeless hatch on a spacecraft.

And so the assignment for creating hinges for Progress Egress, the celebration of the 50th anniversary of the Apollo 11 landing by creating a replica of the command module hatch, went to [Jimmy DiResta]. The hinges were complex linkages that were designed to not only handle the 225 pound (102 kg) hatch on the launch pad, but to allow extended extravehicular activity (EVA) while en route to the Moon. [Jimmy], a multimedia maker, is just as likely to turn metal as he is to work in wood, and his hinges are a study of 1960s aerospace engineering rendered in ipe, and extremely hard and dense tropical hardwood, and brass.

[Jimmy]’s build started with a full-size 3D-printed model of the hinge, a move that paid off as the prints acted both as templates for machining the wood components and as test jigs to make sure everything would articulate properly. Sheet brass was bent and soldered into the hinge brackets, while brass rod stock was turned on the lathe to simulate the hydraulic cylinder hinge stays of the original. The dark ipe and the brass work really well together, and should go nicely with [Fran Blanche]’s walnut and brass latch on the assembled hatch.

With [Adam Savage]’s final assembly of all the parts scheduled for Thursday the 18th, we’re down to the wire on this celebration of both Apollo and the maker movement that was at least in part born from it.

Note: the assembly started at 11:00 Eastern time, and there’s a live stream at https://airandspace.si.edu/events/project-egress-build.

Verizon’s first 5G MiFi mobile hotspot costs $650 (data not included)

Liliputing - พฤ, 07/18/2019 - 22:20

The first 5G wireless networks are starting to come online, and the first 5G-capable smartphones are starting to hit the market. Now Verizon is also launching its first 5G mobile hotspot which you can use to connect a laptop, tablet, or other devices to Verizon’s high-speed cellular network. It comes at a cost though — […]

The post Verizon’s first 5G MiFi mobile hotspot costs $650 (data not included) appeared first on Liliputing.

Asus ROG Phone 2 coming soon (Gaming phone with Snapdragon 855+ and a 5800 mAh battery)

Liliputing - พฤ, 07/18/2019 - 21:10

Over the past few years a bunch of smartphone makers have released smartphones aimed at gamers. But the ASUS ROG Phone stands out from the crowd due to its design, features, support for optional add-ons, and its pedigree (Asus has been selling gaming laptops and desktops under the ROG/Republic of Gamers brand for years). So […]

The post Asus ROG Phone 2 coming soon (Gaming phone with Snapdragon 855+ and a 5800 mAh battery) appeared first on Liliputing.

Blacksmithing For The Uninitiated: Curves And Rings

Hackaday - พฤ, 07/18/2019 - 21:01

You know the funny looking side of the anvil? That’s where the best curves come from. It’s called the anvil horn and is the blacksmith’s friend when bending steel and shaping it into curves.

The principle of bending a piece of steel stock is very easy to understand. Heat it up to temperature, and hammer it over a curved profile to the intended shape. A gentler touch is required than when you are shaping metal. That’s because the intent is to bend the metal rather than deform. Let’s take a look!

Basics of Curves

Light the fire on your hearth as before, and take a piece of steel stock. I suggest a smaller size if you can get it for easier working, 8mm (3/8″) if it is available and over 500mm (20″) long to give you plenty of space for experimentation. You’ll need to position it in the heat such that  150 to 200mm (6″ to 8″) is brought to the usual orange-yellow heat.

On the anvil, place the heated part of your steel across the horn at right angles to it and hammer it over the curvature about halfway along the horn’s length. Depth of curve is controlled by moving along the horn. Working closer to the face of the anvil gives a shallower curve, towards the point gives a sharper one.

When shaping metal you hammer right on the face of the anvil like we did last time. But with curves you aren’t hammering against the anvil because this will change the shape of your work piece. Instead hammer a little distance out from the horn where your steel is in free space. Pretty quickly you’ll start to form a curve, and unless you’re very lucky you’ll probably see it also start to form a spiral. This is straightforward to rectify, simply hammer the developing spiral flat again on the face of the anvil.

Once you’ve got the hang of curves, this is where you can start to experiment and have some fun. Have a go at S shapes, compound curves, and even scrolls if you like. It’s easy enough to undo your experiments and try something else, simply hammer them out flat again on the face of the anvil and start again. Take your time, get creative, and get a feel for how the steel works on the anvil.

Better Put a Ring On It At first your right angle will look more like a tight curve, you’ll need to put in some extra hammering to tighten it up.

Having mastered bending metal, have a go at making a ring on the end of a piece of straight steel stock. You’ll be familiar with the relationship between diameter and circumference of a circle being Pi. Estimate a length that is about 3.141 times your desired radius of the ring. This 3:1 ratio is much easier to estimate than trying to envision the length of a finished curve.

The first part of making your ring is to put a right-angle bend in the steel to make an “L” shape for the base of the ring.

Making a right angle is easy enough, simply heat up the area about 25mm (1″) either side of the position you want to see the bend, lay the piece of stock across the face of the anvil, and hammer it down over the side of the anvil. You’ll have to do some hammering flat around the bend to make it a sharp 90-degrees, as it will at first try to be a sharp curve rather than a point. It may also “pinch” outwards at the corners or even bend outwards slightly away from the right angle, simply hammer that flat on the face of the anvil.

A Trip Around the Horn Forming the loop on the horn of the anvil.

Heat up the foot of the “L”, and take care not to heat up the steel beyond the right angle. You may wish to carefully quench any other parts that have been heated up, leaving only the foot of the “L” at temperature. Then lay the hot part across the horn of the anvil with the cold side of the right angle at 90 degrees to the horn, and hammer a curve round the horn. Continue it round until it touches the right angle. You may have created an oval or a spiral, but that doesn’t matter. You can flatten any spiral tendencies out of the plane of the ring on the face of the anvil, and the next step will render it into a perfect circle.

Your imperfect ring should now be heated up again, once more as much as possible keeping the heat from going up the shaft. Then place it over the end of the horn and hammer it to a circle around it. You may need a few cycles of hammering any spiral tendencies flat, or gently hammering a gap closed if one opens up, but you should eventually be able to make a pretty good circular ring on the end of your piece of bar.

A pair of slightly rough-and-ready rings made in this way.

This should provide plenty of scope for experimentation with curves and rings, but it’s by no means the entire scope. You might for instance want to decrease the size of the stock in a taper over 100mm (4″) or so (See the previous  piece on putting new profiles on a piece of stock or making a point for ideas how you might do that), and then create a decreasing radius curve with that. It’s not too difficult to create the traditional shepherd’s crook design in this way, for example, or to move towards the kind of decorative scrollwork you might see in blacksmith-made gates and railings.

There’s a wealth of interesting things to learn in the blacksmith’s shop and I plan to help demystify the craft and encourage readers to give it a go. Perhaps in a few decades some of you will be passing it on to a fresh cadre of interested hardware hackers. I’ll be back soon with another installment, I’m thinking of tackling the thorny subject of hardness, changing the properties of a piece of steel through heat. See you next time!

Torturing an Instrumented Dive Watch, for Science

Hackaday - พฤ, 07/18/2019 - 18:00

The Internet is a wild and wooly place where people can spout off about anything with impunity. If you sound like you know what you’re talking about and throw around a few bits of the appropriate jargon, chances are good that somebody out there will believe whatever you’re selling.

Case in point: those that purport that watches rated for 300-meter dives will leak if you wiggle them around too much in the shower. Seems preposterous, but rather than just dismiss the claim, [Kristopher Marciniak] chose to disprove it with a tiny wireless pressure sensor stuffed into a dive watch case. The idea occurred to him when his gaze fell across an ESP-01 module next to a watch on his bench. Figuring the two needed to get together, he ordered a BMP280 pressure sensor board, tiny enough itself to fit anywhere. Teamed up with a small LiPo pack, everything was stuffed into an Invicta dive watch case. A little code was added to log the temperature and pressure and transmit the results over WiFi, and [Kristopher] was off to torture test his setup.

The first interesting result is how exquisitely sensitive the sensor is, and how much a small change in temperature can affect the pressure inside the case. The watch took a simulated dive to 70 meters in a pressure vessel, which only increased the internal pressure marginally, and took a skin-flaying shower with a 2300-PSI (16 MPa) pressure washer, also with minimal impact. The video below shows the results, but the take-home message is that a dive watch that leaks in the shower isn’t much of a dive watch.

Hats off to [Kristopher] for doing the work here. We always love citizen science efforts such as this, whether it’s hardware-free radio astronomy or sampling whale snot with a drone.

The Arduboy, Ported To Desktop and Back Again

Hackaday - พฤ, 07/18/2019 - 15:00

A neat little hacker project that’s flying off the workbenches recently is the Arduboy. This tiny game console looks like a miniaturized version of the O.G. Game Boy, but it is explicitly designed to be hacked. It’s basically an Arduino board with a display and a few buttons, anyway.

[rv6502] got their hands on an Arduboy and realized that while there were some 3D games, there was nothing that had filled polygons, or really anything resembling a modern 3D engine. This had to be rectified, and the result is pretty close to Star Fox on a microcontroller.

This project began with a simple test on the Arduboy to see if it would be even possible to render 3D objects at any reasonable speed. This test was just a rotating cube, and everything looked good. Then began a long process of figuring out how fast the engine could go, what kind of display would suit the OLED best, and how to interact in a 3D world with limited controls.

Considering this is a fairly significant engineering project, the fastest way to produce code isn’t to debug code on a microcontroller. This project demanded a native PC port, so all the testing could happen on the PC without having to program the Flash every time. That allowed [rv] to throw out the Arduino IDE and USB library; if you’re writing everything on a PC and only uploading a hex file to a microcontroller at the end, you simply don’t need it.

One of the significant advances of the graphics capability of the Arduboy comes from exploring the addressing modes of the OLED. By default, the display is in a ‘horizontal mode’ which works for 2D blitting, but not for rasterizing polygons. The ‘vertical addressing mode’, on the other hand, allows for a block of memory, 8 x 128 bytes, that maps directly to the display. Shove those bytes over, and there’s no math necessary to display an image.

This is, simply, one of the best software development builds we’ve seen. It’s full of clever tricks (like simply not doing math if you’ll never need the result) and stuffing animations into far fewer bytes than you would expect. You can check out the demo video below.

3 Ways You Can Protect Your Company

MCU Project everyday - พฤ, 07/18/2019 - 14:38

Protecting your company is paramount. Without protection, you could lose everything you have worked so hard for over the years, and if that happens, you could find yourself in a lot of trouble – you might also not have the heart to start all over again. It’s crucial that you are protected as much as possible, and here are some ways it can be done.

Be Aware Of Cyber Attacks

Perhaps one of the most significant issues for businesses today is the problem of potential cyber attacks. In the past, this wasn’t something that anyone needed to worry about – it was real criminals, not virtual ones, that was the problem. Today, though, with all the new technologies that are at our fingertips, and that we use for our business daily, cybercriminals are a very real problem.

To prevent any kind of attack from this direction, you can use a variety of different products, many of which you can buy from Sonicwall UK. They include:

  • Installing a firewall
  • Adding spam filters
  • Installing antivirus software, which can be used by customers who have a firewall appliance in place.

You can also train your staff to ensure that they understand the dangers that might be presented to them and how they can stay away from them.

Strong Passwords

Think of all the times you need to use passwords in your day to day life – it’s probably a lot. When it comes to your businesses, the same will be valid. So, you need to make your passwords secure and difficult (ideally impossible) to guess. Otherwise, you are inviting problems for yourself and your business.

A strong password should include both letters and numbers, and if you can, you should also contain special characters that will make it even harder to hack into. Plus, you should use a different password for every login you need. This sounds like hard work, but imagine if someone were to guess your password and you used it for everything – you could lose it all.

Another tip is to change your password every six months to confuse would-be cybercriminals. This way, even if someone is close to working out what your password is, they won’t be able to use it (or use it for long), if you keep changing it.

CCTV

Protecting the building in which you work is also essential. If you only concentrate on the online space, you could leave yourself open to all kinds of vulnerabilities in the real world. Your computing equipment, sensitive information, and any money or other assets such as vehicles that you have in or near your business building, could all be stolen. One way to combat this threat is to install CCTV. This could be connected to your smartphone, so as soon as any movement is sensed, you will be alerted to it. This can stop issues before they even begin, and will save your business. CCTV is a great deterrent too; if you have it, it will be much less likely that someone will try to steal from you.

BornHack Tease Us With Their Badge

Hackaday - พฤ, 07/18/2019 - 12:00

Every August for the past four years, there has been a summer hacker camp on the Danish island of Bornholm, that may be a relatively new kid on the block but is slowly evolving into one of the summer’s essential stop-offs. This year for the first time they are moving to a larger site in an easier-to-reach part of the country, and in the usual build-up to the event they have released a teaser image of their badge.

Of course, you will want to know a little more about it than the picture can convey, so the BornHack folks were kind enough to give us a few more details. At its heart is a Silicon Labs Happy Gecko EFM32HG322F64G microcontroller, the same 25 MHz ultra-low-power ARM Cortex M0+ part that has featured in the previous BornHack offerings. Power comes from a pair of AA cells, and it sports a 240 x 240 pixel colour IPS display and an SD card holder. Connectivity is via USB and an infra-red interface for badge-to-badge communication, and human interface is via a mini joystick switch. Finally, it has a six-way v1.69bis Shitty Addon connector.

By some standards this is a relatively modest offering, but by using an evolution of their hardware from previous years as well as the same proven Geckoboot bootloader they are far more likely to deliver a satisfactory user experience than had they opted for a more ambitious design. We’ll be attending the camp, so we’ll report on the finished article once we have it.

BornHack will run from the 8th to the 15th of August, on the Danish island of Funen. There are a range of tickets still available, from single day visits to the whole week for 1200 DKK (about €160, or $181). Compared to some other events on our community’s calendar, we think that represents a bargain.

Art Meets Science In The Cold Wastelands Of Iceland

Hackaday - พฤ, 07/18/2019 - 09:00

Although Iceland is now a popular destination for the day-tripping selfie-seeking Instagrammer who rents a 4×4, drives it off road onto delicate ecosystems and then videos the ensuing rescue when the cops arrive, there are still some genuine photographers prepared to put a huge amount of time and effort into their art. [Dheera Venkatraman] is one of the latter and produces composite photos using a relatively low resolution thermal camera and DIY pan and tilt rig.

Whilst we don’t have the exact details, we think that, since the Seek Reveal Pro camera used has a resolution of 320 x 240, [Dheera] would have had to take at least 20 photos for each panoramic shot. In post processing, the shots were meticulously recombined into stunning landscape photos which are a real inspiration to anybody interested in photography.

If you do go to Iceland you might find the traditional food a little challenging to those not raised upon it, nor would you go there for a stag night as beer is eyewateringly expensive. But if you enjoy uninhabitable, desolate, dramatic landscapes there is a huge range of possibilities for the photographer from rugged, frozen lava flows to extra terrestrial ‘Martian’ crater-scapes, if you know where to find them.

[Dheera’s] blog contains some more information about his Iceland photography and there’s a Github repsoitory too. And if you cant afford a $699 Seek Reveal Pro, maybe try building one yourself.

High-Tech Alms Collection With The ESP32

Hackaday - พฤ, 07/18/2019 - 06:00

In an ideal world, shop space, tools, and components would be free. But until we get to that Star Trek utopia, hackerspaces will have to rely on donations from the community to help stay afloat. While asking for money, at least you can have some fun with it if you design and build an Internet-connected donation box.

Or at least that’s how [Goran Mahovlic] handled it for the Radiona hackerspace in Zagreb, Croatia. Not content with just cutting a slit in the top of a shoe box, he came up with a physical donation system that’s not only more informative for those donating, but more organized for those collecting the funds.

The key is a arcade-style programmable coin acceptor from SparkFun. When connected to a microcontroller, this allows the box to keep a running tally on how much money has been inserted. With the use of a RFM96 LoRa module, it can even report on the current haul while remaining mobile; perfect for when the hackerspace has events outside of their home base.

But counting quarters is hardly a task befitting a powerful microcontroller like the ESP32. So [Goran] gave the chip something to do in its spare time by adding a couple of buttons and an LCD. This allows the user to scroll through a list of various projects that are looking for donations, and decide which one they want to financially support. When the donation box counts how much money has been inserted, it records which project its been earmarked for.

Of course, if you’d rather the free market do its thing, we’ve seen this same coin acceptor used to build a locker-sized vending machine. Or if you’re feeling crafty, you could always try your hand at building one with cardboard.

A Fruity Approach To CNC Design

Hackaday - พฤ, 07/18/2019 - 03:00

[Frank Howarth] found himself in need of a lamp for his dining room. Being of the maker persuasion, store-bought simply wouldn’t do. With a serious wood shop at his disposal, [Frank] took a trip down to the supermarket for inspiration (Youtube link, embedded below).

Having picked out a particularly well-formed starfruit for his project, [Frank] didn’t want to spend an inordinately long time attempting to recreate the organic lumps and bumps in modelling software, Instead, Meshroom was used to create a model through photogrammetry. After several failed attempts, success was achieved by using a textured rotating table as a background, with the starfruit painted in matte grey and a final dusting of black speckle. This gave the software enough visual cues to accurately model the fruit’s geometry.

With a 3D model to hand, Fusion Slicer was then used to generate a model that could be constructed out of flat lasercut pieces. The cutting outlines were then generated and passed to Rhino for final tweaking. With everything ready, parts were cut out of plywood and a small mockup of a potential lamp design was created. [Frank] is currently workshopping the design with the inhabitants of the dining room, prior to the final build.

Photogrammetry and modern CAD tools make working with natural forms quick and easy. We’ve also seen the technology used for other purposes too, with [Eric Strebel] providing a great example on how to use it for reverse engineering.

The starfruit tag on Hackaday is pretty sparse, so if you’ve got a project, let us know. Video after the break.

3D Printed Prosthesis Reads Your Mind, Sees With Its Hand

Hackaday - พฤ, 07/18/2019 - 01:30

Hobbyist electronics and robotics are getting cheaper and easier to build as time moves on, and one advantage of that is the possibility of affordable prosthetics. A great example is this transhumeral prosthesis from [Duy], his entry for this year’s Hackaday Prize.

With ten degrees of freedom, including individual fingers, two axes for the thumb and enough wrist movement for the hand to wave with, this is already a pretty impressive robotics build in and of itself. The features don’t stop there however. The entire prosthesis is modular and can be used in different configurations, and it’s all 3D printed for ease of customization and manufacturing. Along with the myoelectric sensor which is how these prostheses are usually controlled, [Duy] also designed the hand to be controlled with computer vision and brain-controlled interfaces.

The palm of the hand has a camera embedded in it, and by passing that feed through CV software the hand can recognize and track objects the user moves it close to. This makes it easier to grab onto them, since the different gripping patterns required for each object can be programmed into the Raspberry Pi controlling the actuators. Because the alpha-wave BCI may not offer enough discernment for a full range of movement of each finger, this is where computer aid can help the prosthesis feel more natural to the user.

We’ve seen a fair amount of creative custom prostheses here, like this one which uses AI to allow the user to play music with it, and this one which gives its user a tattoo machine for an appendage.

The HackadayPrize2019 is Sponsored by:





Tuning into Atomic Radio: Quantum Technique Unlocks Laser-Based Radio Reception

Hackaday - พฤ, 07/18/2019 - 00:01

The basic technology of radio hasn’t changed much since an Italian marquis first blasted telegraph messages across the Atlantic using a souped-up spark plug and a couple of coils of wire. Then as now, receiving radio waves relies on antennas of just the right shape and size to use the energy in the radio waves to induce a current that can be amplified, filtered, and demodulated, and changed into an audio waveform.

That basic equation may be set to change soon, though, as direct receivers made from an exotic phase of matter are developed and commercialized. Atomic radio, which does not rely on the trappings of traditional radio receivers, is poised to open a new window on the RF spectrum, one that is less subject to interference, takes up less space, and has much broader bandwidth than current receiver technologies. And surprisingly, it relies on just a small cloud of gas and a couple of lasers to work.

Quantum Music using Rydberg Atoms

The term atomic radio seems a bit confusing at first. After all, aren’t all radios made from atoms? But in the context of differentiating traditional radio technologies from the newer approach, use of the term atomic makes sense. Atomic radio relies on Rydberg atoms, which are atoms of elements such as cesium and rubidium that have had their outer electrons coaxed into much, much higher quantum states than normal matter, using either laser light at exactly the right wavelength or other electromagnetic methods. The electrons are so far from the nucleus in Rydberg atoms that they are barely held in orbit, the orbits are nearly circular, and the atom approaches macroscopic size.

Because of the highly excited outer electrons, Rydberg atoms have interesting and useful properties. The spacing between electron levels that far out from the nucleus is extremely narrow, making it very easy to perturb electrons and make them change states. If, say, a passing radio wave hits a Rydberg atom, its outer electrons can be nudged to another level. What’s more, Rydberg atoms show the nonlinear optical property of electromagnetically induced transparency, or EIT. That means that a laser tuned to a specific frequency can saturate a gas of Rydberg atoms, rendering them optically transparent in a narrow slice of the spectrum. A second laser tuned to that optical window will shine right through the gas with little loss of intensity.

Atomic radio combines these two properties: a small cell full of excited cesium vapor is rendered transparent with a laser tuned to 852 nm. The cell also has a laser at 510 nm passing through it to a photodiode. When a microwave signal is transmitted through the cell, the vapor’s transparency is reduced proportionally to the strength of the incident radio wave, which results in a signal from the photodiode that can be amplified. This means that unlike conventional radio antennas that operate electromagnetically, atomic radio directly detects radio waves optically.

No Static at All A commercially available vapor cell, the business end of an atomic radio. Source: Rydberg Technologies, Inc.

In a way, atomic radio hearkens back to the aforementioned days of spark gap radios. The earliest radio receivers used coherers to detect passing radio waves. Coherers were simple glass tubes filled with iron filings that had metal contacts at each end. Under normal conditions, the iron filings would not be very conductive, owing to insulating oxides creating a high-resistance path through the loosely packed particles. But a passing radio wave would cause the filings to clump together, reducing the resistance through the coherer and causing it to conduct. The radio wave’s passage could be indicated with a bell or a light.

Of course, coherers need a device called a decoherer, which was essentially a solenoid to gently tap the tube and reset the iron filings to a loose, non-conductive state. An atomic radio receiver needs no such resetting, and as recent work by David Anderson, Rachel Sapiro, and Georg Raithel shows, it is capable of receiving modulated signals, both AM and FM, which coherers were not. Still, the analogy is apt.

The simplicity of atomic radio is attractive. There are no tuned circuits, no intermediate amplifiers, no RF mixers, and critically, no antenna in the traditional sense. Radio waves are detected directly based on how they interact optically with the Rydberg atoms. This means that the stages of a traditional radio receiver that are subject to picking up interference are not present in an atomic radio, resulting in a much lower tendency to pick up noise. And because the Rydberg atom vapor is sensitive to a wide range of radio frequencies, an atomic radio is a broadband receiver — the one demonstrated in the above paper had a four-octave range, from the C-band to the Q-band, or 4 GHz to 50 GHz.

Living in Stereo

More recently, Christopher Holloway et al at the National Institute of Standards and Technology demonstrated an atomic radio that can receive two signals at once. The vapor cell in this radio contained a mix of cesium and rubidium, and each channel required two lasers — one to saturate each species to transparency, and one to probe for RF. Two guitars were played into audio amps (the authors took pains to note that the amps had gain knobs that go to 11) which were used to modulate two microwave signal generators at different frequencies in the 20 GHz range. The probing lasers were directed through the cell and into two separate photodiodes using optical splitters, resulting in a stereo atomic radio.

A two-channel atomic radio receiver. A mixture of cesium and rubidium is excited to Ryberg states and probed for changes in optical transparency at two different frequencies with lasers of different wavelengths. Source: C.L. Holloway, M.T. Simons, A.H. Haddab, C.J. Williams, and M.W. Holloway, AIP Advances 9, 065110 (2019). https://doi.org/10.1063/1.5099036

Atomic radio is at once both simple and complex — simple in that it bypasses most of the traditional circuitry of radio receivers and detects radio waves directly, but complex because it takes a physics lab full of lasers and optics to make it work. So it’s not likely that rank-and-file hobbyists will be building their own atomic radios anytime soon, and hams won’t be tearing down their half-wave dipole antennas in favor of cesium vapor cells. But atomic radio has a lot of potential, especially in deep-space communications applications, and if it can be miniaturized sufficiently, we just might see another commercialization of quantum theory.

Flashing LEDs With MIDI, Note By Note

Hackaday - พุธ, 07/17/2019 - 22:30

Musical keyboards that light up the correct notes to play have long been touted as a quick and easy way to learn how to play. They’re also fun to look at. [Shootingmaker] has developed a similar concept, with a keyboard lookalike, covered in LEDs (Youtube video, embedded below).

The project consists of a PCB, in which the design of the mask imitates the white and black notes of a piano. This makes it look like a keyboard, but as far as we can tell, it doesn’t actually work as one. All the notes are fitted with APA102 addressable LEDs, under the control of a Teensy 3.2 board, operating in USB-MIDI mode. The Teensy receives MIDI data, and then directs the individual LEDs to flash in different colors based on which MIDI channel fired the note.

It’s a fun way to visualise MIDI data, and we think it would be even more fun combined with a basic synthesis engine to make some noise. We suspect it wouldn’t be too hard to integrate the project into an existing instrument, either. Software is available on Github for those interested in replicating the project. You can use MIDI to control neon lights, too.

Daily Deals (7-17-2019)

Liliputing - พุธ, 07/17/2019 - 22:28

Pick up a new Fire tablet or Kindle on Prime Day? Then you might be looking for something to read — and Amazon is running one of its weekly Kindle eBook sales with up to 80-percent off on select titles. Didn’t score a cheap Kindle or Fire tablet? Woot’s got you covered — a refurbished […]

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Nokia 2.2 now available for $139 (Android One, Face unlock, removable battery)

Liliputing - พุธ, 07/17/2019 - 21:31

After making a debut in Europe and India last month, the Nokia 2.2 budget smartphone is now available the United States. Priced at $139, this phone clearly isn’t a flagship device. But it does have some attractive specs including 3GB of RAM, 32GB of storage, Android One software, and a 3,000 mAh battery — which […]

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Counter-Strike at 20: Two Hackers Upend the Gaming Industry

Hackaday - พุธ, 07/17/2019 - 21:01

Choices matter. You’ve only got one shot to fulfill the objective. A single coordinated effort is required to defuse the bomb, release the hostages, or outlast the opposition. Fail, and there’s no telling when you’ll get your next shot. This is the world that Counter-Strike presented to PC players in 1999, and the paradigm shift it presented was greater than it’s deceptively simple namesake would suggest.

The reckless push forward mantra of Unreal Tournament coupled with the unrelenting speed of Quake dominated the PC FPS mind-share back then. Deathmatch with a side of CTF (capture the flag) was all anyone really played. With blazing fast respawns and rocket launchers featured as standard kit, there was little thought put towards conservative play tactics. The same sumo clash of combatants over the ever-so inconveniently placed power weapon played out time and again; while frag counts came in mega/ultra/monster-sized stacks. It was all easy come, easy go.

Counter-Strike didn’t follow the quick frag, wipe, repeat model. Counter-Strike wasn’t concerned with creating fantastical weaponry from the future. Counter-Strike was grounded in reality. Military counter terrorist forces seek to undermine an opposing terrorist team. Each side has their own objectives and weapon sets, and the in-game economy can swing the battle wildly at the start of each new round. What began as a fun project for a couple of college kids went on to become one of the most influential multiplayer games ever, and after twenty years it’s still leaving the competition in the de_dust(2).

Even if you’ve never camped with an AWP, the story of Counter-Strike is a story of an open platform that invited creative modifications and community-driven development. Not only is Counter-Strike an amazing game, it’s an amazing story.

“When Half-Life was released I said, ‘okay, yeah this is a great engine. I’m going to make a mod for this.’…So, I started way before the SDK was released. Once the SDK got out, I just did the code, (and) that pretty much took about a month.”
Minh Le, Counter-Strike Co-Creator

An Open Source Floods The Net with Creativity

Legendary FPS game creators John Romero [Doom, left] and Minh Le [Counter Strike, right].It’s been said that all great things in PC gaming come from Quake. Valve Corporation’s seminal release, Half-Life, was crafted using a modified version of the Quake engine they called Source. Upon the game’s release in 1998 it instantly resonated with PC game fans going as far to elevate the game to “instant classic” status. Valve would only endear themselves further with the hardcore PC crowd when they released a software development kit for Source the next year.

Among those that sought to take advantage of that SDK were Minh Le and Jess Cliffe, couple of university students deeply embedded in the Quake modding community. The duo may have been separated by the Canada-US border, but had found the right time to collaborate on an original project after working as part of the Action Quake 2 mod team. Le had a fascination with military special forces and sought to incorporate actual firearms in lieu of Half-Life’s alien tech. This project was to be a multiplayer affair the military team needed an opposition, and rather than pit country against country a generic “terrorist” team was used. The game mode in it’s simplest terms had the special forces team seeking to counter the objectives being carried out by the terrorists, and thus Counter-Strike was born.

In the early days of Counter-Strike, Le and Cliffe had to do a fair bit of begging for beta testers. However, after being featured as part of the Half-Life Mod Expo ’99 thousands of players across the Internet’s message boards took notice. Feedback came fast for the mod which turned into a number of beta releases, and along with that influx came hundreds of community made maps. The issue became disseminating updates as download mirrors could only serve so many requests. Counter-Strike was usurping games like Unreal Tournament at competitive PC gaming events across the world, but too many were being left out of the fun because after all 56k is only a theoretical speed on dial-up.

“When Counter-Strike first became a Valve property, one of the immediate tasks was to figure out what was going on with updates…That was really the genesis of the idea for Steam, (it) was to figure out how can we automatically update all these folks.”
Doug Lombardi, VP of Marketing Valve Software

The Counter-Strike Culture Goes Corporate

Counter-Strike reached an official 1.0 release in November 2000. That milestone also codified that the game was no longer a mod, but a full release in it’s own right. The rag-tag Counter-Strike team of amateurs was now working under the professional banner of Valve Software, and Sierra Studios, the publisher of Half-Life, would soon fill retail shelves with the game now known as “Half-Life: Counter-Strike”. That name would not stick as Counter-Strike would continue to iterate until reaching it’s ultimate version 1.6 on PC. At that point Counter-Strike as a brand began to expand beyond it’s initial creator’s hands.

Counter-Strike: Condition Zero (better known as the one that fans don’t like to talk about) represented a break from the standard objective based multiplayer of the original. It was primarily a single player experience, though a multiplayer suite was eventually included. The game was considered to be a “tortured project” being passed between three separate game studios during its development. Counter-Strike: Condition Zero would eventually limp to release in 2004, but fans and critics agreed the game was decidedly behind the times. The original iteration of the Source engine had taken Counter-Strike as far as it could go.

That could have been the end of the series if it were not for Counter-Strike: Source being released the very same year. This game was merely a remake of Counter-Strike and a few of its most popular maps to Valve Software’s newly minted Source 2.0 engine, but the title would ultimately serve a higher purpose for the company. It was thrown in as a bundled item for purchasers of Half-Life 2, though secretly Counter-Strike: Source seeded the digital game libraries of PC gamers through Steam. The title’s ubiquity amongst Steam users meant that matches can be found even today, and the endless engagements between the terrorists and counter-terrorist teams still sees thousands of concurrent players daily.

Counter-Strike may have been a product of the last century, but its objective-based multiplayer format has stood the test of time. And it makes a great case study for open development: if Valve hadn’t made the Half-Life SDK available to coders everywhere, one of the most groundbreaking games of the last 20 years wouldn’t have been written.

Bonus Fact: Turtle Rock Studios, developers of Counter-Strike: Condition Zero, would go onto use their experience with creating Counter-Strike bots to serve as the AI for the zombies of Left 4 Dead.

New Nintendo Switch offers 2+ hours of extra battery life

Liliputing - พุธ, 07/17/2019 - 20:35

A week after introducing a new Nintendo Switch Lite handheld game console (without removable controllers or a TV docking station), Nintendo has unveiled an update to the original Nintendo Switch. It’s the same as the original in most respects, but according to the Nintendo website, the new model will get 4.5 to 9 hours of […]

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