Construction Cranes Versus Hurricanes

October 15, 2018 by Bryan Cockfield 14 Comments

When engineers are designing buildings, bridges, or other large construction projects, a lot of thought is given to the environment. Some of these considerations might seem obvious, like designing a skyscraper in San Francisco to tolerate earthquakes, building a stadium in New York City to hold up not only its own weight but the weight of several feet of snow on the roof, or constructing bridges in any coastal area to be able to tolerate salt spray. Not everything is this straightforward, though. Not only do the structures themselves have to tolerate the environmental conditions they are in, but the equipment that is used to build them must tolerate these conditions as well, specifically the large cranes that are often semi-permanently attached to their construction sites.

Perhaps the most extreme example of this in recent memory was during Typhoon Manghut as it hit Hong Kong. There were several large construction cranes that didn’t fare too well with the high winds. At least one toppled as a result and catching the free-spinning of another on video is more than enough to make you gasp. Other videos of construction cranes surfaced from this typhoon showing some concerning, but surprisingly well-designed, emergency operation of the same type of crane.

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Shedding A Bit Of Light On Some Logic

October 15, 2018 by Jenny List 30 Comments

When it comes to logic technologies, we like to think we’ve seen them all here at Hackaday. But our community never ceases to surprise us with its variety and ingenuity, so it should be a surprise that [Dr Cockroach] has delivered one we’ve not seen before. Light logic doesn’t use the conventional active devices you’d expect such as transistors, tubes, or even relays. Instead, it uses LEDs and CdS cells to make rudimentary switches. So far there is a NAND, a NOR, and a set-reset latch that appears in the video below the break, and it is not inconceivable that much more complex devices could be crafted.

The CdS cell switch is not too far different in operation to a transistor, with the CdS cell forming half of a potential divider as a rough equivalent of a collector-emitter circuit, and the LED feeding its light to the cell and forming a rough equivalent of a base circuit. It would probably not form a very good analog of a transistor and it seems likely that is will not be the fastest of devices, but we applaud the ingenuity in coming up with it.

CdS cells are a component that seems almost to come from another era, redolent of childhood electronic kits from days of yore. It’s no surprise we don’t see them too often, though, they pop up in the occasional automatic sunglasses.

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Degaussing Coil To Restore Gameplay Like It’s 1985

October 15, 2018 by Steven Dufresne 24 Comments

You may think that cathode ray tube (CRT) TVs and monitors have gone the way of the dinosaur, but you’d be wrong. Many still have them for playing video games at home or in arcades, for vintage computing, and yes, even for watching television programs. [Nesmaniac] uses his TV for playing Super Mario Bros but for several years it had a red area in the top right corner due to a nearby lightning strike. Sadly, it stood out particularly well against the game’s blue background. His solution was to make a degaussing coil.

We have an article explaining degaussing in detail but in brief, the red was caused by that area of the metal shadow mask at the front of the display becoming magnetized by the lightning strike. One way to get rid of the red area is to bring a coil near it and gradually move the coil away. The coil has AC from a wall socket running through it, producing an oscillating magnetic field which randomizes the magnetic field on the shadow mask, restoring the colors to their former glory.

You’ll find [Nesmaniac’s] video explaining how he made it below. It’s a little cartoonish but the details are all there, along with the necessary safety warnings. His degaussing coil definitely qualifies as a hack. The coil itself came from a 15″ CRT monitor and his on/off switch came from a jigsaw. A 100 watt light bulb serves as a resistance to minimize current and if more or less current is needed then the bulb can be swapped for one with a different wattage.

To demonstrate it in action and give a few more construction details, we’ve included a second video below by [Arcade Jason] who made his for degaussing arcade game screens.

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