Inputs Of Interest: Ears To Communication For Everyone

February 19, 2020 by 20 Comments

Welcome back to Inputs of Interest! If you haven’t heard, I am all ears when it comes to new ways of talking to computers and machines. And speaking of ears, did you know they can do useful tricks? If you squeeze your eyes shut tightly and/or yawn widely, you might hear a low-level rumbling sound like distant thunder. A decent percentage of people are able to move theirs voluntarily, but not everyone. Maybe you already knew you could rumble, and have used it to entertain yourself, or dampen the unpleasant sounds of life.

No, you can’t reach your tensor tympani with a Q-tip. Image via Research Gate

That rumbling is caused by a muscle in your middle ear stretching out. It’s called the tensor tympani, and its purpose is to shield your ears from loud sounds like chewing, and oddly enough, thunder. When the tensor tympani are activated, they pull the eardrums taut to keep them from vibrating and getting damaged. Unfortunately, they don’t react quickly enough to protect us from sudden sounds like gunshots.

Nick G is able to rumble on command, and wanted to see if he could somehow use it as an input mechanism that he calls Earswitch. He got a cheap USB otoscope camera and figured out that the tensor tympani’s stretching movement shows up well enough to trigger motion detection software. So far, [Nick] has been able to demonstrate control of a few things, like the Windows on-screen keyboard, Grid3 assistive software, and a head tracking utility.

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3D Print Your 3D Scanner

February 19, 2020 by 15 Comments

[QLRO] wanted a 3D scanner, but didn’t like any of the existing designs. Some were too complex. Some were simple but required you to do things by hand. That led to him designing his own that he calls AAScan. You can see the thing operating in the video below.

In general, you can move the camera around the object or you can move the object around while the camera stays fixed. This design chooses the latter. You’ll need a stepper motor with a driver board and an Arduino to make the turntable rotate. You also need a computer running Python and Meshroom. The phone also has to run Python and [QLRO] used QPython on an Android device.

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MakerBot Targets Schools With Rebranded Printers

February 19, 2020 by 34 Comments

MakerBot was poised to be one of the greatest success stories of the open source hardware movement. Founded on the shared knowledge of the RepRap community, they created the first practical desktop 3D printer aimed at consumers over a decade ago. But today, after being bought out by Stratasys and abandoning their open source roots, the company is all but completely absent in the market they helped to create. Cheaper and better printers, some of which built on that same RepRap lineage, have completely taken over in the consumer space; forcing MakerBot to refocus their efforts on professional and educational customers.

This fundamental restructuring of the company is perhaps nowhere more evident than in the recent unveiling of “SKETCH Classroom”: an $1,800 package that includes lesson plans, a teacher certification program, several rolls of filament, and two of the company’s new SKETCH printers. It even includes access to MakerBot Cloud, a new online service that aims to help teachers juggle student’s print jobs between multiple SKETCH printers.

Of course, the biggest takeaway from this announcement for the average Hackaday reader is that MakerBot is releasing new hardware. Their last printer was clearly not designed (or priced) for makers, and even a current-generation Replicator costs more than the entire SKETCH Classroom package. On the surface, it might seem like this is a return to a more reasonable pricing model for MakeBot’s products; something that could even help them regain some of the market share they’ve lost over the years.

There’s only one problem, MakerBot didn’t actually make the SKETCH. This once industry-leading company has now come full-circle, and is using a rebranded printer as the keystone of their push into the educational market. Whether they were unable to build a printer cheap enough to appeal to schools or simply didn’t want to, the message is clear: if you can’t beat them, join them.

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Hacked Prosthesis Leads To Mind-Controlled Electronic Music

February 19, 2020 by 14 Comments

As amazing as prosthetic limbs have become, and as life-changing as they can be for the wearer, they’re still far from perfect. Prosthetic hands, for instance, often lack the precise control needed for fine tasks. That’s a problem for [Bertolt Meyer], an electronic musician with a passion for synthesizers with tiny knobs, a problem he solved by hacking his prosthetic arm to control synthesizers with his mind. (Video, embedded below.)

If that sounds overwrought, it’s not; [Bertolt]’s lower arm prosthesis is electromyographically (EMG) controlled through electrodes placed on the skin of his residual limb. In normal use, he can control the servos inside the hand simply by thinking about moving muscles. After experimenting a bit with an old hand, he discovered that the amplifiers in the prosthesis could produce a proportional control signal based on his inputs, and with a little help from synthesizer manufacturer KOMA Electronik, he came up with a circuit that can replace his hand and generate multiple control voltage channels. Plugged into any of the CV jacks on his Eurorack modular synths, he now has direct mind control of his music.

We have to say this is a pretty slick hack, and hats off to [Bertolt] for being willing to do the experiments and for enlisting the right expertise to get the job done. Interested in the potential for EMG control? Of course there’s a dev board for that, and [Bil Herd]’s EMG signal processing primer should prove helpful as well.

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Gear Up Your Gear Knowledge With Gears

February 19, 2020 by 16 Comments

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.

MNIST Clock Uses Famous Training Database

February 18, 2020 by 6 Comments

When training neural networks to recognise things, what you need is a big pile of training data. You then need a subsequent pile of testing data to verify that the network is working as you’d expect. In the field of handwriting recognition, the MNIST database is commonly used to train networks on handwritten numerals. After [Evan Pu] mentioned it would be fun to use this data to create a clock, [Dheera Venkatraman] got down to work.

The original sketch which inspired the build.

The MNIST database contains 60,000 training images, and 10,000 test images. [Dheera] selected an ESP32 to run the project, which packs 4MB of flash storage – more than enough to store the testing database at 196 bytes per numeral. This also gives the project network connectivity, allowing the clock to use Network Time Protocol to stay synchronised – thus eliminating the need for an external RTC. Digits are displayed on four separate e-ink displays, which fits well with the hand-drawn aesthetic. It also means the clock doesn’t unduly light up the room at night.

It’s a fun project that will likely draw a knowing chuckle from those working in the field of handwriting recognition. We’d love to have one on our desk, too. If you’re thinking of attempting a build yourself, check out our recent contest for more inspiration!

Everything You Wanted To Know About 3D Printing Support But Were Afraid To Ask

February 18, 2020 by 6 Comments

At the dawn of 3D printing, support structures were something to avoid. ABS is a hard substance to clear off, and the slicers did a comparatively poor job of making structures that were easy to remove. Today, supports are not a big deal and most of the slicers and materials allow for high-quality prints with supports. We were printing something with supports the other day and noticed that Cura has a support floor and roof function. Curious, we did a quick search and found this very comprehensive post about the current state of support.

With 25 topics in the table of contents, this isn’t a 3-minute read. Of course, you might wish to skip over some of the first parts if you get why you need support and understand the basic ideas. We became more interested when we reached the geometry section.

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