Author: Brian McEvoy

266 Articles

Distorted Text Says A Lot

May 31, 2018 by 21 Comments

Getting bounced to a website by scanning a QR code is no longer an exciting feat of technology, but what if you scanned the ingredient list on your granola bar and it went to the company’s page for that specific flavor, sans the matrix code?

Bright minds at the Columbia University in the City of New York have “perturbed” ordinary font characters so the average human eye won’t pick up the changes. Even ordinary OCR won’t miss a beat when it looks at a passage with a hidden message. After all, these “perturbed” glyphs are like a perfectly legible character viewed through a drop of water. When a camera is looking for these secret messages, those minor tweaks speak volumes.

The system is diabolically simple. Each character can be distorted according to an algorithm and a second variable. Changing that second variable is like twisting a distorted lens, or a water drop but the afterimage can be decoded and the variable extracted. This kind of encoding can survive a trip to the printer, unlike a purely digital hidden message.

Hidden messages like these are not limited to passing notes, metadata can be attached to any text and extracted when necessary. Literature could include notes without taking up page space so teachers could include helpful notes and a cell phone could be like an x-ray machine to see what the teacher wants to show. For example, you could define what “crypto” actually means.

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Plant Biology Is A Gateway

May 23, 2018 by 7 Comments

Too many college students have been subject to teachers’ aids who think they are too clever to be stuck teaching mere underclassmen. For that reason, [The Thought Emporium] is important because he approaches learning with gusto and is always ready to learn something new himself and teach anyone who wants to learn. When he released a video about staining and observing plant samples, he avoided the biggest pitfalls often seen in college or high school labs. Instead of calling out the steps by rote, he walks us through them with useful camera angles and close-ups. Rather than just pointing at a bottle and saying, “the blue one,” he tells us what is inside and why it is essential. Instead of telling us precisely what we need to see to get a passing grade, he lets our minds wonder about what we might see and shows us examples that make the experiment seem exciting. The video can also be seen below the break.

The process of staining can be found in a biology textbook, and some people learn best by reading, but we haven’t read a manual that makes a rudimentary lab seem like the wardrobe to Narnia, so he gets credit for that. Admittedly, you have to handle a wicked sharp razor, and the chance of failure is never zero. In fact, he will tell you, the opportunities to fail are everywhere. The road to science isn’t freshly paved, it needs pavers.

If a biology lab isn’t in your personal budget, a hackerspace may have one or need one. If you are wondering where you’ve heard [The Thought Emporium]’s voice before, it is because he is fighting lactose intolerance like a hacker.

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Smiling Robot Moves Without Wires

May 22, 2018 by 11 Comments

What could be cuter than a little robot that scuttles around its playpen and smiles all day? For the 2018 Hackaday prize [bobricius] is sharing his 2D Actuator for Micro Magnetic Robot. The name is not so cute, but it boasts a bill of materials under ten USD, so it should be perfect for educational use, which is why it is being created.

The double-layer circuit board hides six poles. Three poles run vertically, and three of them run horizontally. Each pole is analogous to a winding in a stepper motor. As the poles turn on, the magnetic shuttle moves to the nearest active pole. When the perpendicular windings activate, it becomes possible to lock that shuttle in place. As the windings activate in sequence, it becomes possible to move left/right and forward/back. The second video demonstrates this perfectly.

[bobricius] found inspiration from a scarier source, but wants us to know this is his creation, not a patent infringement. We are not lawyers.

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Slipcasting Resin Prototypes

May 20, 2018 by 11 Comments

[Eric Strebel] doesn’t need an introduction anymore. If there is a picture of an elegantly designed part with a professional finish on our pages, there is a good chance he has a hand in it. This time he is sharing his method of making a part which looks like it is blow-molded but it is not. Blow-molded parts have a distinctive look, especially made with a transparent material and [Eric’s] method certainly passes for it. This could upgrade your prototyping game if you need a few custom parts that look like solidified soap bubbles.

Mold making is not covered in this video, which can also be seen below the break, but we can help you out with a tip or two. For demonstration’s sake, we see the creation of a medical part which has some irregular surfaces. Resin is mixed and degassed then rolled around inside the mold. Then, the big reveal, resin is allowed to drain from the mold. Repeat to achieve the desired thickness.

This is a technique adapted from ceramics called slipcasting. For the curious, an elegant ceramic slipcasting video demonstration can be seen below as well. For an added finishing touch, watch how a laquer logo is applied to the finished part; a touch that will move the look of your build beyond that of a slapdash prototype.

More education from this prolific maker can be seen in his video on painting with a professional-looking finish and his tips for working with foam-core.

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Scrapped Motors Don’t Care About Direction

May 19, 2018 by 18 Comments

Spinners built into games of chance like roulette or tabletop board games stop on a random number after being given a good spin. There is no trick, but they eventually rest because of friction, no matter how hard your siblings wind up for a game-winning turn. What if the spinning continued forever and there was no programming because there was no controller? [Ludic Science] shows us his method of making a perpetual spinner with nothing fancier than a scrapped hard disk drive motor and a transformer. His video can also be seen below the break.

Fair warning: this involves mains power. The brushless motor inside a hard disk drive relies on three-phase current of varying frequencies, but the power coming off a single transformer is going to be single-phase AC at fifty or sixty Hz. This simplifies things considerably, but we lose the self-starting ability of the motor and direction control, but we call those features in our perpetual spinner. With two missing phases, our brushless motor limps along in whatever direction we initiate, but the circuit couldn’t be much more straightforward.

This is just the latest skill on a scrapped HDD motor’s résumé (CV). They will run with a 9V battery, or work backwards and become an encoder. If you want to use it more like the manufacturer’s intent, consider this controller.

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People With Dementia Can DRESS Smarter

May 19, 2018 by 9 Comments

People with dementia have trouble with some of the things we take for granted, including dressing themselves. It can be a remarkably difficult task involving skills like balance, pattern recognition inside of other patterns, ordering, gross motor skill, and dexterity to name a few. Just because something is common, doesn’t mean it is easy. The good folks at NYU Rory Meyers College of Nursing, Arizona State University, and MGH Institute of Health Professions talked with a caregiver focus group to find a way for patients to regain their privacy and replace frustration with independence.

Although this is in the context of medical assistance, this represents one of the ways we can offload cognition or judgment to computers. The system works by detecting movement when someone approaches the dresser with five drawers. Vocal directions and green lights on the top drawer light up when it is time to open the drawer and don the clothing inside. Once the system detects the article is being worn appropriately, the next drawer’s light comes one. A camera seeks a matrix code on each piece of clothing, and if it times out, a caregiver is notified. There is no need for an internet connection, nor should one be given.

Currently, the system has a good track record with identifying the clothing, but it is not proficient at detecting when it is worn correctly, which could lead to frustrating false alarms. Matrix codes seemed like a logical choice since they could adhere to any article of clothing and get washed repeatedly but there has to be a more reliable way. Perhaps IR reflective threads could be sewn into clothing with varying stitch lengths, so the inside and outside patterns are inverted to detect when clothing is inside-out. Perhaps a combination of IR reflective and absorbing material could make large codes without being visible to the human eye. How would you make a machine-washable, machine-readable visual code?

Helping people with dementia is not easy but we are not afraid to start, like this music player. If matrix codes and barcodes get you moving, check out this hacked scrap-store barcode scanner.

Thank you, [Qes] for the tip.

Gentle Electric Eel

May 16, 2018 by 22 Comments

It’s no shock that electric eels get a bad rap for being scary creatures. They are slithery fleshy water snakes who can call down lightning. Biologists and engineers at the University of California had something else in mind when they designed their electric eel. Instead of hunting fish, this one swims harmlessly alongside them.

Traditional remotely operated vehicles have relied on hard shells and spinning propellers. To marine life, this is noisy and unnatural. A silent swimmer doesn’t raise any eyebrows, not that fish have eyebrows. The most innovative feature is the artificial muscles, and although the details are scarce, they seem to use a medium on the inside to conduct a charge, and on the outside, the saltwater environment conducts an opposite charge which causes a contraction in the membrane between to the inside and outside. Some swimming action can be seen below the break, and maybe one of our astute readers can shed some light on this underwater adventurer’s bill of materials.

One of our favorite submarines is the 2017 Hackaday Prize winner, The Open Source Underwater Glider. For a more artistic twist on submersibles, the Curv II is one of the most elegant we have seen.

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