Gear Up Your Gear Knowledge With Gears

Gears are fairly straightforward way to couple rotational motion, and the physics topics required to understand them are encountered in an entry level physics classroom, not a university degree. But to really dig down to the root of how gears transfer motion may be somewhat more complex than it seems. [Bartosz Ciechanowski] put together an astonishingly good interactive teaching tool on gears, covering the fundamentals of motion up through multi-stage gear trains.

Illustrating the distance traveled at different points on the disc

The post starts at the beginning – not “how to calculate a gear ratio” – but how does rotational motion work at all. The illustrations help give the reader an intuitive sense for how the rate of rotation is measured and what that measurement actually represents in the real world. From there [Bartosz] builds up to describing how two discs touching edge to edge transfer motion and the relationship of their size on that process. After explaining torque he has the fundamentals in place to describe why gears have teeth, and why they work at all.

Well written explanatory copy aside, the real joy in this post is the interactivity. Each concept is illustrated, and each illustration is interactive. Images are accompanied by a slider which lets you adjust what’s shown, either changing the speed of a rotating gear or advancing the motion of two teeth interlocking. We found that being able to move through time this way really helped form an intuitive understanding of the concepts being discussed. This feels like the dream of interactive multimedia textbooks come to life.

This Machine Teaches Sign Language

Sign language can like any language be difficult to learn if you’re not immersed in it, or at least learning from someone who is fluent. It’s not easy to know when you’re making minor mistakes or missing nuances. It’s a medium with its own unique issues when learning, so if you want to learn and don’t have access to someone who knows the language you might want to reach for the next best thing: a machine that can teach you.

This project comes from three of [Bruce Land]’s senior electrical and computer engineering students, [Alicia], [Raul], and [Kerry], as part of their final design class at Cornell University. Someone who wishes to learn the sign language alphabet slips on a glove outfitted with position sensors for each finger. A computer inside the device shows each letter’s proper sign on a screen, and then checks the sensors from the glove to ensure that the hand is in the proper position. Two letters include making a gesture as well, and the device is able to track this by use of a gyroscope and compass to ensure that the letter has been properly signed. It appears to only cover the alphabet and not a wider vocabulary, but as a proof of concept it is very effective.

The students show that it is entirely possible to learn the alphabet reliably using the machine as a teaching tool. This type of technology could be useful for other applications as well, such as gesture recognition for a human interface device. If you want to see more of these interesting and well-referenced senior design builds we’ve featured quite a few, from polygraph machines to a sonar system for a bicycle.

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Learn Verilog In Your Browser

We are big fans of tools in the browser for education. You have a consistent environment maintained by someone else, you don’t have to install anything, and you can work from any computer you happen to find yourself. The HDLBits site has a great set of Verilog “exams” that would be a big help to anyone trying to learn or brush up on their Verilog skills.

The site offers a range of topics that go from the silly (output a constant 1 or 0) to full-blown state machines and testbenches. The site isn’t tutorial in nature, instead it offers a problem, an optional hint, and an editing window with some code already in place. You add your code and hit submit. Behind the scenes, the site runs Intel Quartus and Modelsim to test your work. It will either show you the results or tell you that you failed.

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Medium Machine Mediates Microcontroller Messages

Connecting computers to human brains is currently limited to the scope of science fiction and a few cutting-edge laboratories. Tapping into some nerves farther from our central wetware is possible and [Peter Buczkowski] shows us his stylish machine for implanting a pattern into our brains without actively having to memorize anything.

His Medium Machine leverages a TENS unit to activate forearm muscles in a pattern programmed into an Arduino. Users place their forearm across two aluminum electrodes mounted on a tasteful wooden platform and extend a single finger over a button. Electrical impulses trigger the muscles which press the button. That’s all. After repeating the pattern a few times, the users should be able to recite it back on command even if they aren’t aware of what it means. If this sounds like some [Johnny Mnemonic] memory cache, you are absolutely correct. This project draws inspiration from the [William Gibson] novel which became a [Keanu Reeves] movie.

Users can be programmed with a Morse code message or the secret knock to open an attic library or play a little tune. How about learning a piano song?

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What’s The Best Way To Learn Electronics?

What’s the best way to learn electronics? It’s a pithy question to ask a Hackaday audience, most of whom are at least conversant in the field already. Those who already have learned often have just their own perspective to draw upon—how they themselves learned. Some of you may have taught others. I want to explore what works and what doesn’t.

Hobbyists Learn Differently Than Students

One thing I can say straight off is that students learn differently than people who learn at home. Hobbyists have the advantage of actually being interested, which is a quality a student may not enjoy. People have been teaching themselves electronics since the beginning, with analog projects–Heathkit models, BEAM robots, and ham radio sets–evolving into purely digital projects.

Let’s face it, Arduinos lower the bar like nothing else. There’s a reason why the Blink sketch has become the equivalent to “Hello World”. Dirt cheap and easily configured microcontrollers combined with breakout boards make it easy for anyone to participate.

However, ask any true EE and that person will tell you that following wiring diagrams and plugging in sensor boards from Sparkfun only teaches so much. You don’t bone up on terms like hysteresis or bias by building something from uCs and breakout boards. But do you need to? If you are truly interested in electronics and learn by making those Adafruit or Sparkfun projects, sooner or later you’ll want to make your own breakout boards. You’ll learn how to design your own circuit boards and figure out why things work and why they don’t. I don’t need to tell you the Internet has all the answers a neophyte needs–but the interest has to be there in the first place.

What’s the Best Way to Learn in the Classroom?

There is a product category within robotics kits that consists of “educational rovers” designed to be purchased in group lots by teachers so that each student or small group gets one. These rovers are either pre-built or mostly built—sure, you get to screw in motor mounts, but all the circuit boards are already soldered up for you, surface mount, no less. They come pre-configured for a variety of simple tasks like line following and obstacle avoidance. The Makeblock mBot is an example.

I think it’s part of that whole “learn coding” initiative, where the idea is to minimize the assembly in order to maximize the coding time. Insofar as soldering together a kit of through-hole components teaches about electronics, these bots mostly don’t do it. By all appearances, if there is a best way to learn electronics, this an’t it. However, regardless of what kind of project the teacher puts in front of the student, it still has to generate some sort of passion. What those robots provide is a moment of coolness that ignites the firestorm of interest.

I once led a soldering class that used Blinky Grids by Wayne and Layne as the focus. This is a fantastic kit that guides you through building a small LED matrix. It’s particularly cool because it can be programmed over a computer monitor with light sensors interacting with white and black squares on the company’s web site. When my students finished their grids, they all worked and had unique messages scrolling through. Now, that is a payoff. I’m not saying that any of those folks became hardware hackers as a result of my class, but it beat the hell out of a Christmas tree, am I right?

Getting back to that rover, what must be acknowledged is that the rover itself is the payoff, and that’s only as far as it goes if everyone loses interest. However, a lot of those rovers have expansion possibilities like bolting on another sensor or changing the method of programming–for instance, the mBot has both a graphic programming interface and can also be reflashed with a regular old Arduino bootloader.

Readers, share in comments your own perspective. How did you learn? How would you teach others?

The Science Behind Boost Converters

[Ludic Science] shows us the basic principles that lie behind the humble boost converter. We all take them for granted, especially when you can make your own boost converter or buy one for only a few dollars, but sometimes it’s good to get back to basics and understand exactly how things work.

The circuit in question is probably as simple as it gets when it comes to a boost converter, and is not really a practical design. However it helps visualize what is going on, and exactly how a boost converter works, using just a few parts, a screw, enameled wire, diode, capacitor and a push button installed on a board.

The video goes on to show us the science behind a boost converter, starting with adding a battery from which the inductor stores a charge in the form of an electromagnetic field. When the button is released, the magnetic field collapses, and this causes a voltage in the circuit which is then fed through a diode and charges the capacitor a little bit. If you toggle the switch fast enough the capacitor will continue to charge, and its voltage will start to rise. This then creates a larger voltage on the output than the input voltage, depending on the value of the inductor. If you were to use this design in a real life application, of course you would use a transistor to do the switching rather than a push button, it’s so much faster and you won’t get a sore finger.

This is very basic stuff,  but the video gives us a great explanation of what is happening in the circuit and why. If you liked this article, we’re sure you’ll love Hackaday’s own [Jenny List] explain everything you need to know about inductors.

(updated thanks to [Unferium] – I made a mistake about the magnetic field collapsing when the button is pressed , When in reality it’s when the button is released that this happens. Apologies for confusion.)

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“You Sank My Dysprosium!”: Periodic Table Battleship

Kids these days, they have it so easy. Back in the old days, we learned our elements the hard way, by listening to “The Elements” by Tom Lehrer over and over until the vinyl wore out on the LP. Now, thanks to [Karyn], kids can learn the elements by playing “Battleship” – no tongue-twisting lyrics required.

For anyone familiar with the classic “Battleship” game, you’ll wonder why no one thought of this before. [Karyn]’s version of the game is decidedly low-tech, but gets the job done. She printed out four copies of the periodic table, added letters to label the rows, and laminated them. A pair of tables goes into a manila file folder, the tops get clipped together, and dry-erase markers are used to mark out blocks of two to five elements to represent the ships of the Elemental Navy on the lower table. Guesses at the location of the enemy ships can be made by row and series labels for the elementally challenged, or better yet by element name. Hits and misses are marked with Xs and Os on the upper table, and play proceeds until that carrier hiding in the Actinide Archipelago is finally destroyed.

This is pure genius in its simplicity and practicality, but of course there’s room for improvement. The action-packed video after the break reveals some structural problems with the file folders, so that’s an obvious version 2.0 upgrade. And you can easily see how this could be used for other tabular material – Multiplication Table Battleship? Sounds good to us. And if your nippers catch the chemistry bug from this, be sure to take a deeper dive into the structure of the periodic table with them.

Now, if you’ll excuse me: “There’s antimony, arsenic, aluminum, selenium, and hydrogen and oxygen and nitrogen and rhenium….”

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