Finally, A Fidget Spinner We Can Love

We’ve been frankly mystified at the popularity of fidget spinners. After all, we can flip an ink pen around just fine. However, [MakersBox] just sold us on what he calls the geek spinner. The fact that the spinner is actually a PCB and has parts on it, would probably have been cool enough. However, the spinner also has a persistence of vision LED set up and can display 12 characters of text as it spins. Because the board is simple and uses through hole components, it would be a great project for a budding young hacker. You can see a video below.

The instructions are geared towards someone attempting their first project, too. If you know how to solder and insert a DIP IC, you might find you’ll skim them, but it is pretty straightforward. The 8 LEDs on one side operate from an ATTiny CPU, which you can program with an Arduino. The spinner has a hall effect sensor and a magnet to figure out the index position of the spin — crucial for displaying text.

Although the board attempts to balance the components, the battery side is apparently a little heavy. The suggestion is to add some weight using some hardware or solder to that side. Speaking of solder, the bearing in the center solders to the PCB. That’s going to take a lot of heat, so maybe you can finally use Dad’s soldering gun that has been gathering dust under your bench.

We liked the polar graph provided to help you set up the code for your own messages. The text implies there is a picture of one of these graphs filled out, but we think he forgot to include that picture. However, it is clear enough how to use it, and it would make it very easy to make your own text or any design that the spinner could produce.

This isn’t the first POV spinner, by the way. [MakersBox] has a nice set of acknowledgments for projects he’s seen or borrowed from, but the other one he mentions uses surface mount. Granted, surface mount isn’t a problem for most people these days, but starting out, it might be nice to stick with a through-hole design. If you want a more useful spinner, you can always make some music.

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magicShifter 3000: An Over-Engineered POV Stick with a 15-Year Journey

3 hackers, 16 LEDs, 15 years of development, one goal: A persistence of vision display stick that fits into your pocket. That’s the magicShifter 3000. When waved, the little, 10 cm (4 inches) long handheld device draws stable images in midair using the persistence of vision effect. Now, the project has reached another milestone: production.

The design has evolved since it started with a green LED bargraph around 2002. The current version features 16 APA102 (aka DotStar) RGB LEDs, an ESP-12E WiFi module, an NXP accelerometer/magnetometer, the mandatory Silabs USB interface, as well as a LiPo battery and charger with an impressive portion of power management. An Arduino-friendly firmware implements image stabilization as well as a React-based web interface for uploading and drawing images.

After experimenting with Seeedstudio for their previous prototypes, the team manufactured 500 units in Bulgaria. Their project took them on a roundtrip through hardware manufacturing. From ironing out minuscule flaws for a rock-solid design, over building test rigs and writing test procedures, to yield management. All magicShifter enclosures are — traditionally — 3D printed, so [Overflo] and [Martin] are working in shifts to start the 500 prints, which take about 50 minutes each to complete. The printers are still buzzing, but assembled units can be obtained in their shop.

Over all the years, the magicShifter has earned fame and funding as the over-engineered open hardware pocket POV stick. If you’re living in Europe, chances are that you either already saw one of the numerous prototype units or ran into [Phillip Tiefenbacher] aka [wizard23] on a random hacker event to be given a brief demo of the magicShifter. The project always documented the status quo of hardware hacking: Every year, it got a bit smaller, better, and reflected what parts happened to be en vogue.

magicshifter-timeline

The firmware and 3D-printable enclosure are still open source and the schematics for the latest design can be found on GitHub. Although, you will search in vain for layout or Gerber files. The risk of manufacturing large batches and then being put out of business by cheap clones put its mark on the project, letting the magicShifter reflect the current, globalized status of hardware hacking once more. Nevertheless, we’re glad the bedrock of POV projects still persists. Check out the catchy explanatory video below.

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Shedding Light on the Mechanics of Film Projection

Do you know how a film projector works? We thought we did, but [Bill Hammack] made us think twice. We have covered the Engineer Guy’s  incredibly informative videos many times in the past, and for good reason. He not only has a knack for clear explanation, the dulcet tones of his delivery are hypnotically soothing. In [Bill]’s latest video, he tears down a 1979 Bell & Howell 16mm projector to probe its inner workings.

Movies operate on the persistence of vision (POV) principle, which basically states that the human brain creates the illusion of motion from still images. If you’ve ever drawn circles and figure eights in the nighttime air with a sparkler or perused a flip book, then you’ve experimented with POV.

A film projector is no different in theory. Still images on a strip of celluloid are passed between a lamp and a lens, which project the images on to a screen. A device called a shuttle advances the film by engaging its teeth into the holes on the edge of the film and moving downward, pulling the film with it. The shuttle then disengages its teeth and moves up and forward, starting the process again.

shuttersFilm is projected at a rate of 24 frames per second, which is sufficient to create the POV illusion. A projector’s shutter inserts itself between the lamp and the lens, blocking the light to prevent projection of the film’s physical movement. But these short periods of darkness, or flicker, present a problem. Originally, shutters were made in the shape of a semi-circle, so they block the light half of the time. Someone figured out that increasing the flicker rate to 60-70 times per second would have the effect of constant brightness. And so the modern shutter has three blades: one blocks projection of the film’s movement, and the other two simply increase flicker.

[Bill] explains how the projector reads the optical soundtrack. He also delves into the mechanisms that allow continuous sound playback alongside intermittent projection of the image frames. You’ll never look at a projector the same way again.

Want to know more about optical soundtracks? Check out this Retrotechtacular that explores the subject in detail.

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2 foot tall POV globe

[Ytai] let us know about his POV globe, all four parts of its current progress. While he says he was inspired to write up the project from a YouTube clip, we know the real reason. Regardless, the plan is to have a 2 foot diameter globe with 256 LEDs spinning at 50 revolutions per second streaming images from an SD card using SPI. While the project isn’t completed yet, we know [Ytai] will pull through like he has in the past, and you can be sure we’ll keep you up to date on his progress.

Spin Peggy, get 3D POV

We put a temporary ban on posting POV projects after receiving several LED spheres back in May. But we had to lift the injunction after seeing this superb Volumetric 3D POV display by [Wes Faler] and [Don Smith].

Their creative use of several readily available components adds to the alluring setup; the central elements being just a box fan and Peggy kit from EMSL. The video after the jump doesn’t really do the project justice, but if you missed it at Maker Fair Detroit and can’t make your own it’s the best you’re going to get.

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