The Electrical Outlet And How It Got That Way

May 14, 2018 by Dan Maloney 221 Comments

Right now, if you happen to be in Noth America, chances are pretty good that there’s at least one little face staring at you. Look around and you’ll spy it, probably about 15 inches up from the floor on a nearby wall. It’s the ubiquitous wall outlet, with three holes arranged in a way that can’t help but stimulate the facial recognition firmware of our mammalian brain.

No matter where you go you’ll find those outlets and similar ones, all engineered for specific tasks. But why do they look the way they do? And what’s going on electrically and mechanically behind that familiar plastic face? It’s a topic we’ve touched on before with Jenny List’s take on international mains standards. Now it’s time to take a look inside the common North American wall socket, and how it got that way.

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Scratch-Built Ornithopter: Here’s How I Flapped My Way To Flight

May 11, 2018 by Steven Dufresne 35 Comments

One of humankind’s dreams has always been to fly like a bird. For a hacker, an achievable step along the path to that dream is to make an ornithopter — a machine which flies by flapping its wings. An RC controlled one would be wonderful, controlled flight is what everyone wants. Building a flying machine from scratch is a big enough challenge, and a better jumping-off point is to make a rubber band driven one first.

I experimented with designs which are available on the internet, to learn as much as possible, but I started from scratch in terms of material selection and dimensions. You learn a lot about flight through trial and error, and I’m happy to report that in the end I achieved a great little flyer built with a hobby knife and my own two hands. Since then I’ve been looking back on what made that project work, and it’s turned into a great article for Hackaday. Let’s dig in!

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Inside Mechanical Calculators

May 1, 2018 by Dan Maloney 25 Comments

For as busy as things can get at the grocery store on a typical afternoon just before the dinner hour, at least the modern experience has one thing going for it: it’s relatively quiet. Aside from the mumbled greetings and “Paper or plastic?” questions from the cashier, and the occasional screaming baby in the next aisle, the only sound you tend to hear is the beeping of the barcode scanner as your purchase is tallied up.

Jump back just 40 years and the same scene was raucous, with cashiers reading price tags and pounding numbers into behemoth electromechanical cash registers. Back then, if you wanted help with any arithmetic with more than just a few operations, some kind of mechanical calculator was your only choice. From simple “one-banger” adding machines to complex analog computers, mechanical devices were surprisingly capable data processing tools. Here’s a brief look at how some of the simpler ones worked.

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Decellularization: Apples To Earlobes

April 30, 2018 by Brian McEvoy 40 Comments

Our bodies are not like LEGO blocks or computers because we cannot swap out our parts in the living room while watching television. Organ transplants and cosmetic surgery are currently our options for upgrades, repairs, and augments, but post-transplant therapy can be a lifelong commitment because of rejection. Elective surgery costs more than a NIB Millenium Falcon LEGO set. Laboratories have been improving the processes and associated treatments for decades but experimental labs and even home laboratories are getting in on the action as some creative minds take the stage. These folks aren’t performing surgeries, but they are expanding what is possible to for people to do and learn without a medical license.

One promising gateway to human building blocks is the decellularization and recellularization of organic material. Commercial scaffolds exist but they are expensive, so the average tinkerer isn’t going to be buying a few to play with over a holiday weekend.

Let’s explore what all this means. When something is decellularized, it means that the cells are removed, but the structure holding the cells in place remains. Recellularizing is the process where new cells are grown in that area. Decellularizing is like stripping a Hilton hotel down to the girders. The remaining structures are the ECM or the Extra Cellular Matrix, usually referred to as scaffolding. The structure has a shape but no functionality, like a stripped hotel. The scaffolding can be repopulated with new cells in the same way that our gutted hotel can be rebuilt as a factory, office building, or a hospital.

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Milspec Teardown: AH-64A Apache Data Entry Panel

April 30, 2018 by Tom Nardi 93 Comments

It’s time once again to see how those tax dollars are spent, this time in the form of a “Data Entry Keyboard” manufactured by Hughes Helicopters. This device was built circa 1986 or so, and was used in the AH-64A Apache. Specifically, this panel would have been located by the gunner’s left knee, and served as a general purpose input device for the Apache’s Fire Control System. Eventually the Apache was upgraded with a so-called “glass cockpit”; consolidating various vehicle functions into a handful of multi-purpose digital displays. As such, this particular device became obsolete and was pulled from the active Apache fleet.

The military vehicle aficionados out there may know that while the Apache is currently a product of Boeing, it was originally designed by Hughes Helicopter. In 1984, McDonnell Douglas purchased Hughes Helicopter and took over production of the Apache, and then McDonnell Douglas themselves were merged with Boeing in 1997.

So it’s somewhat interesting that this device bears the name of Hughes Helicopter, as of the time it was manufactured, they would have been known as McDonnell Douglas Helicopter Systems. Presumably they had to work through existing stock of components that already had Hughes branding on them, leaving some transitional examples such as this one.

But you didn’t come here for a history lesson on the American military-industrial complex, you want to know about the hardware itself. So let’s crack it open to see what we can learn about this piece of aviation history.

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Mechanisms: The Lever, It’s Everywhere

April 26, 2018 by Steven Dufresne 28 Comments

Levers are literally all around us. You body uses them to move, pick up a pen to sign your name and you’ll use mechanical advantage to make that ballpoint roll, and that can of soda doesn’t open without a cleverly designed lever.

I got onto this topic quite by accident. I was making an ornithopter and it was having trouble lifting its wings. For the uninitiated, ornithopters are machines which fly by flapping their wings. The problem was that the lever arm was too short. To be honest, as I worked I wasn’t even thinking in terms of levers, and only realized that there was one after I’d fine-tuned its length by trial and error. After that, the presence of a lever was embarrassingly obvious.

I can probably be excused for not seeing a lever right away because it wasn’t the type we most often experience. There are different classes of levers and it’s safe to say that most people aren’t even aware of this. Let’s take a closer look at these super useful, and sometimes hidden mechanisms known as levers.

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Firing Bullets Through Propellers

April 25, 2018 by Steven Dufresne 39 Comments

Early airborne combat was more like a drive-by shooting as pilot used handheld firearms to fire upon other aircraft. Whomever could boost firepower and accuracy would have the upper hand and so machine guns were added to planes. But it certainly wasn’t as simple as just bolting one to the chassis.

This was during World War I which spanned 1914 to 1918 and the controllable airplane had been invented a mere eleven years before. Most airplanes still used wooden frames, fabric-covered wings, and external cable bracing. The engineers became pretty inventive, even finding ways to fire bullets through the path of the wooden propeller blades while somehow not tearing them to splinters.

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