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.
Continue reading “Hacking Shelters And Swimming Pools”
We’ve all come to terms with a neural network doing jobs such as handwriting recognition. The basics have been in place for years and the recent increase in computing power and parallel processing has made it a very practical technology. However, at the core level it is still a digital computer moving bits around just like any other program. That isn’t the case with a new neural network fielded by researchers from the University of Wisconsin, MIT, and Columbia. This panel of special glass requires no electrical power, and is able to recognize gray-scale handwritten numbers.
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According to reports, a turbine-powered flying board buzzed around Bastille Day celebrations carrying its inventor [Franky Zapata] toting a rifle to promote the military applications of the Flyboard Air. You can see the video record, below.
We’ve heard the board costs a cool $250,000 so you may want to start saving now. There are several versions including one that qualifies in the United States as an ultralight. The board Zapata used can reach speeds of 190 km/h and can run for up to 10 minutes, although the website claims 200 km/h is possible and the company also claims to routinely reach 140 km/h. and 6 minute flight times.
Continue reading “Hoverboard Circles Bastille Day”
It is rare to find a car these days without some mechanism for charging a cell phone. After all, phones need charging all the time and we spend a lot of time in our cars. But what if you spend a lot of time on your bike? Five teens from Lynchburg, Virginia decided to build something to charge their phones from pedal power.
This isn’t a new idea, of course. Your alternator is charging your phone in your car, and bikes have had alternators connected to them for lights and other purposes. According to the team, you need to pedal about 4 miles per hour to get enough voltage to charge the phone. You can go faster though, because the circuit has a regulator. We especially liked how they determined the speed versus the voltage using a tachometer and an electric drill. We also liked the 3D printed parts such as the handlebar mount that you could probably repurpose for other things.
Continue reading “Pedal Faster! I Need To Join A Conference Call!”
Although the silicon controlled rectifier or SCR has been around since 1957, it doesn’t get nearly the love an ordinary transistor does. That’s a shame because they are quite handy when it comes to controlling AC and DC voltages in things such as lamp dimmers, motor speed controllers, and even soldering iron temperature controllers. [Lewis Loflin] has a short video introduction that will help you get started with these devices.
One of the interesting properties of the device is that once you turn it on it will stay on until you do something specific to turn it back off — sort of, [Lewis] explains it in the video.
Continue reading “The Basics Of SCRs”
If you ask most people to explain the Fourier series they will tell you how you can decompose any particular wave into a sum of sine waves. We’ve used that explanation before ourselves, and it is not incorrect. In fact, it is how Fourier first worked out his famous series. However, it is only part of the story and master video maker [3Blue1Brown] explains the story in his usual entertaining and informative way. You can see the video below.
Paradoxically, [3Blue1Brown] asserts that it is easier to understand the series by thinking of functions with complex number outputs producing rotating vectors in a two-dimensional space. If you watch the video, you’ll see it is an easier way to work it out and it also lets you draw very cool pictures.
Continue reading “Fourier Explained: [3Blue1Brown] Style!”
You often hear people — especially non-hacker types — complain that money spent on space travel would be better off spent here on Earth. Of course that ignores one big factor, that space programs have resulted in a host of spin off technologies, many of which you use every day. JPL has an infographic that covers twenty things we wouldn’t have without space travel, and while it could be said that some of these things might have been invented anyway it would doubtless have taken much longer without the necessity and the income from space programs. If you want more detail, Tech Briefs has an interesting interview on the subject of what tech spun off the Apollo program.
Some of the inventions are pretty obvious, and others are more refinements of things that already existed. We all knew NASA pioneered freeze drying for food, for instance. However, some of them are pretty surprising. For example, according to the infographic, NASA asking Black and Decker to develop a moon sample collector led to the Dust Buster.
Continue reading “You Are Probably Using NASA Technology”