Author Archives: Adam Fabio

This Boxing Bell is a Trip

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[MeasuredWorkshop] wanted to know how a boxing bell mechanism worked. The best way to learn is by doing, so he jumped right in and built one! Boxing bells are a rare surviving example of the trip bell mechanism. Trip bells were used in schools and public buildings as fire alarms. They’ve since been replaced by modern electric systems.

The mechanical linkage behind the trip bell is a one-way lever. This is the arm you pull on. It has a hinged section which stays rigid when the arm is pulled down, but rotates away when the arm is released. [Measured Workshop] …read more

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IBM 1401 Runs FORTRAN II Once More

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The IBM 1401 is undeniably a classic computer. One of IBM’s most “affordable” mainframes, it ruled the small business computing world of the 1960’s. Unfortunately, computers aren’t often thought of as treasured heirlooms, only a handful of these machines survive today. The computer history museum has two machines. One from Germany, and the other recovered from a basement in Connecticut back in 2008. [CuriousMarc] and the rest of the team at the museum have been working diligently to restore the 1401, and they’ve hit quite a milestone — They can now compile and run FORTRAN II code.

Getting the 1401 …read more

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Flexiphone Rises from the Ashes of Broken Instruments

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The mechanics of an old Rhodes Piano, and a set of chromatic saucer bells rescued from a reed organ. What do these two things have to do with each other? If you’re [Measured Workshop], they are the makings of a new instrument. The Flexiphone is a transposable instrument with a piano keyboard and interchangeable sound source.

The Rhodes is a great stage instrument. Unlike a piano with strings, it uses tines mounted above the key mechanism. It is also relatively compact for an analog instrument. This made it perfect as a donor for the Flexiphone’s keyboard. [Measured Workshop] cut they …read more

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Travel in Style on an Electric Air Sled

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What do you do during the winter months in Ohio? Sledding of course! Sledding normally takes place on hills, but [Peter Sripol] is no slave to the terrain. He’s built an air sled to conquer the barren wastelands of unplowed parking lots. Air sleds aren’t as outlandish as you might think — the Soviet Union had decades of success with them.

The project starts with toboggan style plastic sled. [Peter] built a frame into the plastic using an aluminum square. The frame is used to support a motor pod at the back of the sled. The motor, of course, comes …read more

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Strumbot: The Guitar that Strums Itself

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[Clare] isn’t the most musically inclined person, but she can strum a guitar. Thanks to a little help from an Arduino, she doesn’t even have to do that.

She built the strumbot, which handles the strumming hand duties of playing the guitar. While [Claire] does believe in her strumbot, she didn’t want to drill holes in her guitar, so hot glue and double-sided foam tape were the order of the day.

The business end of the strumbot is a micro servo. The servo moves two chopsticks and draws the pick across the strings. The tiny servo surprisingly does a great …read more

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Chasing the Electron Beam at 380,000 FPS

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Analog TV is dead, but that doesn’t make it any less awesome. [Gavin and Dan], aka The Slow Mo Guys recently posted a video about television screens. Since they have some incredible high-speed cameras at their disposal, we get to see the screens being drawn, both on CRT and more modern LCD televisions.

Now we all know that CRTs draw one pixel at a time, drawing from left to right, top to bottom. You can capture this with a regular still camera at a high shutter speed. The light from a TV screen comes from a phosphor coating pained on …read more

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Repairing A Sunburned Game Boy Screen

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The original Game Boy is a classic. Sure, it had no backlight, but there is something special about playing on that classic green screen. Unfortunately, some of these older systems are suffering a terrible fate — screen burn. Game Boy’s played best with lots of light — especially in out in the sun. But that same sun did terrible things to the screen. A black splotch in the center of the LCD is the telltale sign of a burned Game Boy. You might think that screen replacement is the only option, but [The Retro Future] shows us how to repair …read more

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Cardboard wall is surprisingly well built

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We all built cardboard forts when we were kids. [Paintingcook] has taken it into adulthood with a hand built cardboard wall. He and his wife leased a loft apartment. Lofts are great — one giant space to work with. Plans changed a bit when they found out they had a baby on the way. A single living, working, and sleeping space definitely wouldn’t be good for a newborn, so the couple set about separating a section of the room with a wall.

Sheetrock and steel or wood lumber would be the normal path here. They instead decided to recycle their …read more

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Flying the Friendly Skies with A Hall Effect Joystick

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There are plenty of PC joysticks out there, but that didn’t stop [dizekat] from building his own. Most joysticks mechanically potentiometers or encoders to measure position. Only a few high-end models use Hall effect sensors. That’s the route [dizekat] took.

Hall effect sensors are non-contact devices which measure magnetic fields. They can be used to measure the position and orientation of a magnet. That’s exactly how [dizekat] is using a trio of sensors in his design. The core of the joystick is a universal joint from an old R/C car. The center section of the joint (called a spider) has …read more

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Spectre and Meltdown: How Cache Works

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The year so far has been filled with news of Spectre and Meltdown. These exploits take advantage of features like speculative execution, and memory access timing. What they have in common is the fact that all modern processors use cache to access memory faster. We’ve all heard of cache, but what exactly is it, and how does it allow our computers to run faster?

In the simplest terms, cache is a fast memory. Computers have two storage systems: primary storage (RAM) and secondary storage (Hard Disk, SSD). From the processor’s point of view, loading data or instructions from RAM is …read more

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