Megasquirting My 1983 Datsun Z

September 8, 2016 by Bil Herd 97 Comments

When Dinosaurs Drove to Work

Back in the mid 1980’s I worked at a company called Commodore Business Machines, a company that made home computers where our annual Superbowl was the Consumer Electronics Show in Las Vegas the first week in January.

Some time in November a Datsun Z would get parked in the front lot and then not move until whatever snow mounds that got plowed over it melted sometime in early spring. Ultimately I would have it towed leaving behind a sad little pile of rust and nuts and bolts. With a bonus check in hand for finishing the newest computer on time I would go buy another used Z and repeat the cycle.

Climate Change and Rust

These days the old Datsun Z’s; 240Z, 260Z, 280Z, 280ZX, are somewhat rare, probably because they were real rust buckets even when new. After having sacrificed a few myself in search of the next home computer I set out to rescue one for old times’ sake. I really did love the car so I made it my project to restore one. Now I have a total of three Z carcasses, an engine, and a transmission all sitting out back and an almost finished Z in the garage.

Since I had torn the engine down to its bare components I took the opportunity to make some changes: increased the size of the turbocharger, increased bore and stroke of the cylinder/piston, improved the fuel distribution, and improved the flow of air with things like porting the heads and an inter-cooler.

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The Quantum Eraser

September 7, 2016 by Will Sweatman 64 Comments

Richard Feynmann noted more than once that complementarity is the central mystery that lies at the heart of quantum theory. Complementarity rules the world of the very small… the quantum world, and surmises that particles and waves are indistinguishable from one other. That they are one and the same. That it is nonsensical to think of something, or even try to visualize that something as an individual “particle” or a “wave.” That the particle/wave/whatever-you-want-to-call-it is in this sort of superposition, where it is neither particle nor wave. It is only the act of trying to measure what it is that disengages the cloaking device and the particle or wave nature is revealed. Look for a particle, and you’ll find a particle. Look for a wave instead, and instead you’ll find a wave.

Complementarity arises from the limits placed on measuring things in the quantum world with classical measuring devices. It turns out that when you try to measure things that are really really really small, some issues come up… some fundamental issues. For instance, you can’t really know exactly where a sub-atomic particle is located in space. You can only know where it is within a certain probability, and this probability is distributed through space in the form of a wave. Understanding uncertainty in measurement is key to avoiding the disbelief that hits you when thinking about complementarity.

This article is a continuation of the one linked above. I shall pick up where I left off, in that everyone agrees that measurement on the quantum scale presents some big problems. However, not everyone agrees what these problems mean. Some, such as Albert Einstein, say that just because something cannot be measured doesn’t mean it’s not there. Others, including most mainstream physicists, say the opposite — that if something cannot be measured, it for all practical purposes is not there. We shall continue on our journey by using modern technology to peer into the murky world of complementarity. But first, a quick review.

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How Accurate Is Microstepping Really?

August 29, 2016 by Moritz Walter 162 Comments

Stepper motors divide a full rotation into hundreds of discrete steps, which makes them ideal to precisely control movements, be it in cars, robots, 3D printers or CNC machines. Most stepper motors you’ll encounter in DIY projects, 3D printers, and small CNC machines are bi-polar, 2-phase hybrid stepper motors, either with 200 or — in the high-res variant — with 400 steps per revolution. This results in a step angle of 1.8 °, respectively 0.9 °.

Can you increase the resolution of this stepper motor?

In a way, steps are the pixels of motion, and oftentimes, the given, physical resolution isn’t enough. Hard-switching a stepper motor’s coils in full-step mode (wave-drive) causes the motor to jump from one step position to the next, resulting in overshoot, torque ripple, and vibrations. Also, we want to increase the resolution of a stepper motor for more accurate positioning. Modern stepper motor drivers feature microstepping, a driving technique that squeezes arbitrary numbers of microsteps into every single full-step of a stepper motor, which noticeably reduces vibrations and (supposedly) increases the stepper motor’s resolution and accuracy.

On the one hand, microsteps are really steps that a stepper motor can physically execute, even under load. On the other hand, they usually don’t add to the stepper motor’s positioning accuracy. Microstepping is bound to cause confusion. This article is dedicated to clearing that up a bit and — since it’s a very driver dependent matter — I’ll also compare the microstepping capabilities of the commonly used A4988, DRV8825 and TB6560AHQ motor drivers.

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Hands-On The Shaper Origin: A Tool That Changes How We Build

August 25, 2016 by Gerrit Coetzee 199 Comments

I bet the hand saw really changed some things. One day you’re hacking away at a log with an ax. It’s sweaty, awful work, and the results are never what you’d expect. The next day the clever new apprentice down at the blacksmith’s shop is demoing his beta of his new Saw invention and looking for testers, investors, and a girlfriend. From that day onward the work is never the same again. It’s not an incremental change, it’s a change. Pure and simple.

This is one of those moments. The world of tools is seeing a new change, and I think this is the first of many tools that will change the way we build.

Like most things that are a big change, the components to build them have been around for a while. In fact, most of the time, the actual object in question has existed in some form or another for years. Like a crack in a dam, eventually someone comes up with the variation on the idea that is just right. That actually does what everything else has been promising to do. It’s not new, but it’s the difference between crude and gasoline.

My poetic rasping aside, the Shaper Origin is the future of making things. It’s tempting to boil it down and say that it’s a CNC machine, or a router. It’s just, more than that. It makes us more. Suddenly complex cuts on any flat surface are easy. Really easy. There’s no endless hours with the bandsaw and sander. There’s no need for a 25,000 dollar gantry router to take up half a garage. No need for layout tools. No need to stress about alignment. There’s not even a real need to jump between the tool and a computer. It can be both the design tool and the production tool. It’s like a magic pencil that summons whatever it draws. But even I had to see it to believe it.

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Tools Of The Trade – Test And Programming

August 24, 2016 by Bob Baddeley 15 Comments

In our final installment of Tools of the Trade (with respect to circuit board assembly), we’ll look at how the circuit board is tested and programmed. At this point in the process, the board has been fully assembled with both through hole and surface mount components, and it needs to be verified before shipping or putting it inside an enclosure. We may have already handled some of the verification step in an earlier episode on inspection of the board, but this step is testing the final PCB. Depending on scale, budget, and complexity, there are all kinds of ways to skin this cat.

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RGB LEDs: How To Master Gamma And Hue For Perfect Brightness

August 23, 2016 by Elliot Williams 26 Comments

You would think that there’s nothing to know about RGB LEDs: just buy a (strip of) WS2812s with integrated 24-bit RGB drivers and start shuffling in your data. If you just want to make some shinies, and you don’t care about any sort of accurate color reproduction or consistent brightness, you’re all set.

But if you want to display video, encode data in colors, or just make some pretty art, you might want to think a little bit harder about those RGB values that you’re pushing down the wires. Any LED responds (almost) linearly to pulse-width modulation (PWM), putting out twice as much light when it’s on for twice as long, but the human eye is dramatically nonlinear. You might already know this from the one-LED case, but are you doing it right when you combine red, green, and blue?

It turns out that even getting a color-fade “right” is very tricky. Surprisingly, there’s been new science done on color perception in the last twenty years, even though both eyes and colors have been around approximately forever. In this shorty, I’ll work through just enough to get things 95% right: making yellows, magentas, and cyans about as bright as reds, greens, and blues. In the end, I’ll provide pointers to getting the last 5% right if you really want to geek out. If you’re ready to take your RGB blinkies to the next level, read on!

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Fractals Among Us

August 18, 2016 by Will Sweatman 41 Comments

Think not of what you see, but what it took to produce what you see

Benoit Mandelbrot

Randomness is all around you…or so you think. Consider the various shapes of the morning clouds, the jagged points of Colorado’s Rocky Mountains, the twists and turns of England’s coastline and the forks of a lightning bolt streaking through a dark, stormy sky. Such irregularity is commonplace throughout our natural world. One can also find similar irregular structures in biology. The branch-like structures in your lungs called Bronchi, for instance, fork out in irregular patterns that eerily mirror the way rivers bifurcate into smaller streams. It turns out that these irregular structures are not as irregular and random as one might think. They’re self-similar, meaning the overall structure remains the same as you zoom in or out.

The mathematics that describes these irregular shapes and patterns would not be fully understood until the 1970s with the advent of the computer. In 1982, a renegade mathematician by the name of Benoit Mandelbrot published a book entitled “The Fractal Geometry of Nature”. It was a revision of his previous work, “Fractals: Form, Chance and Dimension” which was published a few years before. Today, they are regarded as one of the ten most influential scientific essays of the 20th century.

Mandelbrot coined the term “Fractal,” which is derived from the Latin word fractus, which means irregular or broken. He called himself a “fractalist,” and often referred to his work as “the study of roughness.” In this article, we’re going to describe what fractals are and explore areas where fractals are used in modern technology, while saving the more technical aspects for a later article.

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