Resistance In Motion: What You Should Know About Variable Resistors

September 16, 2016 by Steven Dufresne 42 Comments

Adjusting the volume dial on a sound system, sensing your finger position on a touch screen, and knowing when someone’s in the car are just a few examples of where you encounter variable resistors in everyday life. The ability to change resistance means the ability to interact, and that’s why variable resistance devices are found in so many things.

The principles are the same, but there are so many ways to split a volt. Let’s take a look at what goes into rotary pots, rheostats, membrane potentiometers, resistive touchscreens, force sensitive resistors, as well as flex and stretch sensors.

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The Bootup Guide To Homebrew Two-Stage Tentacle Mechanisms

September 13, 2016 by Sonya Vasquez 42 Comments

What’s not to love about animatronics? Just peel back any puppet’s silicone skin to uncover a cluster of mechatronic wizardry that gives it a life on the big screen. I’ve been hunting online for a good intro to these beasts, but I’ve only turned up one detailed resource–albeit a pretty good one–from the Stan Winston Tutorials series. Only 30 seconds into the intro video, I could feel those tentacles waking up my lowest and most gutteral urge to create physical things. Like it or not, I was hooked; I just had to build one… or a few. This is how you built a very real animatronic tentacle.

29172101050_b8d50d333e_z — I built this. And you can too!

If you’re getting started in this realm, I’ll be honest: the Stan Winston Tutorial is actually a great place to start. In about two hours, instructor Richard Landon covers the mindset, the set of go-to components, and the techniques for fabricating a tentacle mechanism with a set of garage tools–not to mention giving us tons of real-film examples along the way [1].

We also get a sneak peek into how we might build more complicated devices from the same basic techniques. I’d like to pick up exactly where he left off: 4-way two-stage tentacles. And, of course, if you’ve picked up on just how much I like a certain laser-cuttable plastic at this point, I’m going to put a modern twist on Landon’s design. These design tweaks should enable you to build your own tentacle and controller with nothing more but a few off-the-shelf parts, some Delrin, and a laser cutter… Ok, fine, a couple 3D printed parts managed to creep their way in too.

In a good-ol’ engineers-for-engineers fashion, I’m doing something a little different for this post: I’m finishing off this series with a set of assembly videos, a BOM, and the original CAD files to make that beast on the front page come to life. As for why, I figured: why not? Even though these mechanisms have lived in the robotics community and film industry for years, they’re still lacking the treatment of a solid, open design. This is my first shot at closing that gap. Get yourself a cup of coffee. I’m about to give you every bleeding detail on the-how-and-why behind these beasts.

All right; let’s get started.

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What Is There To Know About Resistors?

September 6, 2016 by Steven Dufresne 65 Comments

Resistor: A passive chunk of material that resists the flow of electrical current. A terminal is connected to each end you’re done. What could be simpler?

It turns out it’s not so simple at all. Temperature, capacitance, inductance and other factors all play a part in making the resistor a rather complex component after all. Even its uses in circuits are many, but here we’ll just focus on the different types of fixed-value resistors, how they’re made, and what makes them desirable for different applications.

Let’s start with a simple one, and one of the oldest.

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From Project To Kit: After The Sale

September 2, 2016 by Jenny List 29 Comments

However you sell your kits online, you’ll have to find a means of shipping them to the customer. For an online operation this unseen part of the offering is more important than any other when it comes to customer satisfaction, yet so many large players get it so wrong.

This is the final article in a series looking on the process of creating and selling a commercial kit from a personal electronic project (read all the posts in this series). We’ve looked at the market, assembling the kit and its instructions, and how to set up an online sales channel. In this part we’ll look at what happens when you’ve made the sale, how to get it safely to the customer and how to keep the customer happy after the sale by offering support for your products. We’ll also give a nod to marketing your site, ensuring a fresh supply of customers.

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How The Human Brain Stores Data

September 1, 2016 by Will Sweatman 119 Comments

Evolution is one clever fellow. Next time you’re strolling about outdoors, pick up a pine cone and take a look at the layout of the bract scales. You’ll find an unmistakable geometric structure. In fact, this same structure can be seen in the petals of a rose, the seeds of a sunflower and even the cochlea bone in your inner ear. Look closely enough, and you’ll find this spiraling structure everywhere. It’s based on a series of integers called the Fibonacci sequence. Leonardo Bonacci discovered the sequence while trying to figure out how many rabbits he could make starting with just two. It’s quite simple — add the right most integer to the previous one to get the next one in the sequence. Starting from zero, this would give you 0-1-1-2-3-5-8-13-21 and so on. If one was to look at this sequence in the form of geometric shapes, they can create square tiles whose sides are the length of the value in the sequence. If you connect the diagonal corners of these tiles with an infinite curve, you end up with the spiral that you saw in the pine cone and other natural objects.

So how did mother nature discover this geometric structure? Surely it does not know math. How then can it come up with intricate and sophisticated structures? It turns out that this Fibonacci spiral is the most efficient way of squeezing the most amount of stuff in the least amount of space. And if one takes natural selection seriously, this makes perfect sense. Eons of trial and error to make the most copies of itself has stumbled upon a mathematical principle that permeates life on earth.

The homo sapiens brain is the product of this same evolutionary process, and has been evolving for an estimated 7 million years. It would be foolish to think that this same type of efficiency natural selection has stumbled across would not be present in the current homo sapiens brain. I want to impress upon you this idea of efficiency. Natural selection discovered the Fibonacci sequence solely because it is the most efficient way to do a particular task. If the brain has a task of storing information, it is perfectly reasonable that millions of years of evolution has honed it so that it does this in the most efficient way possible as well. In this article, we shall explore this idea of efficiency in data storage, and leave you to ponder its applications in the computer sciences.

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Working For Elon Musk

August 31, 2016 by Steven Dufresne 163 Comments

One of my favorite types of science fiction character is found in the books of Ben Bova; a business mogul who through brilliance, hard work, and the force of personality drives mankind to a whole new level in areas such as commercializing space, colonizing the stars, battling governments, and thwarting competitors.

It is possible to name a few such characters in real life — influencing the electricity industry was George Westinghouse, automobiles was Henry Ford, and more recently Steve Jobs and Elon Musk. With Elon’s drive we may all finally be driving electric cars within 20 years and spreading out into space with his cheap rockets. Due to the latter he may be the closest yet to one of Bova’s characters.

So what’s it like to work for Elon Musk at Tesla or SpaceX? Most of us have read articles about him, and much that he’s written himself, as well as watched some of his many interviews and talks. But to get some idea of what it’s like to work for him I greatly enjoyed the insight from Ashlee Vance’s biography Elon Musk – Tesla, SpaceX, and the Quest for a Fantastic Future. To write it Vance had many interviews with Musk as well as those who work with him or have in the past. Through this we get a fascinating look at a contemporary mogul of engineering.

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Hyperuniformity — A Hidden Order Found In The Greatest Set Of Eyes

August 29, 2016 by Will Sweatman 62 Comments

Of all the things evolution has stumbled across, the eye is one of the most remarkable. Acting as sort of a ‘biological electromagnetic transducer’, the eye converts incoming photons into electrical and chemical spikes, known as action potentials. These spikes then drive the brain of the host life form. Billions of years of natural selection has produced several types of eyes, with some better than others. It would be an honest mistake to think that the human eye is at the top of the food chain, as this is not the case. Mammals underwent a long stint scurrying around in dark caves and crevasses, causing our eyes to take a back seat to other more important functions, such as the development of a cortex.

There are color sensitive cones in all eyes. Mammals have three types of cones, which are…wait for it…Red, Blue and Green. Our red and green cones are relatively recent on the evolutionary timescale – appearing about 30 million years ago.

The way these cones are distributed around our eyes is not perfect. They’re scattered around in lumpy, uneven patterns, and thus give us an uneven light sampling of our world. Evolution simply has not had enough time to optimize our eyes.

There is another animal on this planet, however, that never went through “the dark ages” as mammals did. This animal has been soaring high above its predators for over 60 million years, allowing its eyes to reach the pinnacle of the natural selection process. A bald eagle can spot a mouse from over a mile away. Birds eyes have 5 types of light sensitive cones – red, blue and green like our own. But add in violet and a type of cone that can detect no light, or black. But it is the way these cones are distributed around the bird’s eye that is most fascinating, and the subject of today’s article.

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