Parkinson’s Spoon Uses Control Theory For Good

December 6, 2020 by Al Williams 18 Comments

When we first saw [Barqunics’] design for a self-stabilizing spoon for people suffering from Parkinson’s disease, we wondered how well something like that could work. But take a look at the video below and you’ll see this does a fine job of responding to the user’s hand movements and keeping the spoon perfectly level through a wide range of motion.

There’s at least one commercial product that attempts to stabilize a spoon in the same way so that people suffering from that affliction can retain a measure of independence. This shows that you don’t need injection molding and factory made boards to prove the concept. An MPU6050 provides sensor information and two servo motors control the spoon using PID control.

PID — short for proportional, integral, derivative — is a way to adjust something to a desired point. For example, consider trying to heat a cup of water to 95 °C. If you simply turn the heater on full blast until you get to 95 °C, the water will actually get hotter because you’ll overshoot. Using PID, the amount of heating provided will depend on how far off you are now (proportional), how far off you’ve been over the long term (integral), and how much change you’ve effected recently (derivative). The same algorithm works for spoon-balancing and many other types of controls.

This isn’t the first bootstrapped assistive spoon project we’ve seen. We even looked at the commercial version, awhile back.

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Slot Machine Has A Handle On Fun

December 5, 2020 by Kristina Panos 2 Comments

For some reason, when slot machines went digital, they lost their best feature — the handle. Who wants to push a button on a slot machine, anyway? Might as well just play video poker. [John Bradnam] seems to agree, and has built an open-source three-color matrix slot machine complete with handle.

In this case, you’ll be losing all of your nickels to an Arduino Pro Mini. The handle is an upgrade to an earlier slot machine project that uses three 8×8 matrices and a custom driver board. When the spring-loaded handle is pulled, it strikes a micro switch to spins the reels and then snaps back into place. Between each pull, the current score is displayed across the matrix. There’s even a piezo buzzer for victory squawks. We only wish the button under the handle were of the clickier variety, just for the feels. Check out the short demo video after the break.

If you’re not a gambler, you could always turn your slot machine into a clock.

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Fans Add Reality To Virtual Driving

December 5, 2020 by Al Williams 16 Comments

A few decades ago you might have been satisfied with a crude wireframe flight simulator or driving a race car with the WASD keys. Today, gamers expect more realism, and [600,000 milliliters] is no different. At first, he upgraded his race car driving chair and put on VR goggles. But watching the world whiz by in VR is you can’t feel the wind on your face. Armed with a 3D printer, some software, and some repurposed PC fans, he can now feel the real wind in virtual reality. You can see the build in the video, below.

The electronics are relatively straightforward and there is already software available. The key, though, is the giant 3D printed ducts that direct the airflow. These are big prints, so probably not for some printers, but printers are getting bigger every day. The fan parts are from Thingiverse, but the enclosures are custom and you can download them from the blog post.

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Flipbook Automation Saves Your Thumb

December 4, 2020 by Al Williams 3 Comments

You’ve probably seen a flipbook. That’s a book with pictures on each page. Each picture is slightly different than the last one so if you flip rapidly through the book you get a little animation. We like the German word, Daumenkino, which translates as “thumb cinema” and that seems appropriate. [Barqunics] put a decidedly new twist on this old technology. His flipbook senses a viewer and automatically flips the pages using a motor. You can see the Arduino-controlled device in the video below.

The presence detection is a ubiquitous sonar sensor. The frame is easy to make since it uses cardboard and hot glue. A DC motor like you find on many toy cars or robots provides the rotation. No 3D printing needed, but we did think it would be easy to 3D-print or laser-cut the pieces.

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Bet You Didn’t Know Arduinos Are Psychic

November 24, 2020 by Kristina Panos 3 Comments

Are you running out of ways to entertain yourself and your family? If you’ve read all the books and watched all the movies, it might be time to explore the psychic abilities of silicon. [Hari Wiguna] has just the trick to keep them guessing for a good long time.

This trick doesn’t take much, just a couple of Arduinos, some momentary buttons, a number pad, and a large helping of math. As you can see in the demo after the break, there is nothing connecting the two, not even 802.11(n). On the randomizer Arduino, [Hari] generates random numbers with the push of a button until the audience sees one they like. Then [Hari] locks in the number with the other button.

What happens next is key: the randomizer generates another random number, but uses it as a hint to set a sentinel digit. The randomizer Arduino subtracts the larger of the two digits in the number from nine and stores the result as the flag. When the next number comes up that has the flag digit in the correct place, the number after that will be the random number chosen at the beginning.

The psychic Arduino’s secret is that it knows the first guess it receives is special. It does the same sentinel digit math as the randomizer, so when the guesser enters the guess with the sentinel digit, it knows the next number entered is the winner. Clear as mud? Check out the second video below where [Hari] explains the trick, a new take on a magic classic.

Looking for a more exciting way to generate random numbers? Try using fish tanks, lava lamps, or muons from outer space.

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Artistic Robot Has Paints, Will Travel

November 22, 2020 by Lewin Day 1 Comment

Creativity is a very human trait, and one that many try to emulate with robots. Some focus on the cerebral side of things, working with neural networks and machine learning to produce new artistic output. Others work on the mechanical side, building ‘bots that can manipulate tools in the real world for artistic purposes. [Technovation]’s latest build falls into the latter category – a small Arduino-powered ‘bot that likes to paint.

The robot moves around on two wheels, each driven by a stepper motor for accurate movement. The paintbrush itself is controlled with another stepper, which rotates it between the paint pots and the canvas. A servo is used to dip the brush into pots, and to apply it to the canvas. An Arduino Uno runs the show, with the robot currently programmed to paint random lines of various colors on the canvas.

By virtue of its roving design, it could theoretically paint on arbitrarily large canvasses. It’s a platform that could prove highly capable when paired with a neural network and perhaps some machine vision to allow it to concoct more complex artworks. We’ve seen other paint bots before, too. Video after the break.

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3D Print Your Way To A Modular MIDI Playset

November 16, 2020 by Tom Nardi 6 Comments

Have you ever wanted to experiment with MIDI, but didn’t know where to start? Or perhaps you didn’t think you could afford to properly outfit your digital beat laboratory, especially given the average hacker’s penchant for blinkenlights? Well worry no more, as [Johan von Konow] has unveiled a collection of DIY MIDI devices that anyone with a 3D printer can build on the cheap.

The LEET modular synthesizer is made up of a keyboard, drum pad, chord keyboard, arpeggiator and a step sequencer that plug into your computer and interface with industry standard digital audio workstation (DAW) programs. The down side is that they don’t do anything on their own, but this simplification allowed [Johan] to really streamline the design and bring the cost of the build down to the bare minimum.

Integrated wire channels mean no PCB is required.

You don’t need to build all the components either, especially if you’re just testing the waters. The keyboard is a great starting point, and even if you have to buy all the components new from eBay, [Johan] says it shouldn’t cost you more than $10 USD to build. You just need an Arduino Pro Micro, some tact switches, and a section of WS2812 RGB LED strip. There’s an excellent chance you’ve already got some of that in the parts bin, which will make it even cheaper.

There is one missing element though: the PCB. But not because you have to source it yourself. Like his clever Arduboy clone we covered earlier in the year, the 3D printed bodies for all of the LEET devices have integrated wiring channels that serve as a stand-in for a traditional circuit board. Simply place all your components, push some stiff 0.3 mm diameter wire down into the channels, and solder the ends. It’s a very neat approach, and something we could see becoming more popular as desktop 3D printers become an increasingly common sight in the home workshop.

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