A Surprisingly Simple Omnidirectional Display

November 22, 2024 by Danie Conradie 37 Comments

Old-school technology can spark surprising innovations. By combining the vintage zoetrope concept with digital displays, [Mike Ando] created the Andotrope, a surprisingly simple omnidirectional display.

Unlike other 3D displays, the Andotrope lets you view a normal 2D video or images that appear identical irrespective of your viewing angle. The prototype demonstrated in the video below consists of a single smart phone and a black cylinder spinning at 1,800 RPM. A narrow slit in front of each display creates a “scanning” view that our brain interprets as a complete image, thanks to persistence of vision. [Mike] has also created larger version with a higher frame rate, by mounting two tablets back-to-back.

Surprisingly, the Andotrope appears to be an original implementation, and neither [Mike] nor we can find any similar devices with a digital display. We did cover one that used a paper printout in a a similar fashion. [Mike] is currently patenting his design, seeing the potential for smaller displays that need multi-angle visibility. The high rotational speed creates significant centrifugal force, which might limit the size of installations. Critically, display selection matters — any screen flicker becomes glaringly obvious at speed.

This device might be the first of its kind, but we’ve seen plenty of zoetropes over the years, including ones with digital displays or ingenious time-stretching tricks. Continue reading “A Surprisingly Simple Omnidirectional Display” →

3D Zoetrope Uses Illusion To Double The Frames

July 3, 2021 by Kristina Panos 10 Comments

Although film and animation have come quite a long way, there’s still something magical about that grandaddy of them all, the zoetrope. Thanks to persistence of vision, our eyes are fooled into seeing movement where there is none, only carefully laid-out still pictures strobing under the right lighting.

After four months of research, CAD, prototyping, and programming, [Harrison McIntyre] has built a 3D zoetrope that brings a gif to glorious physical life (video, embedded below). All the image pieces are printed and move under a fancy backlight that [Harrison] borrowed from work. It works essentially the same as a 2D zoetrope, as long as you get the spacing juuuuust right. 360° divided by 20 frames comes out to 18° per frame. So a motor spins the disk around, and every 18°, the light pulses for one millisecond and then turns off until the next frame is in position.

The really interesting thing is that there are actually more than 20 frames at play here. If you follow a single character through the loop, it takes 46 frames to complete the animation thanks to something 3D zoetrope pioneer [Kevin Holmes] dubbed ‘animation multiplexing‘, which in [Harrison]’s example, is easily explained as a relay race in which all runners run their section at the same time, creating the illusion of constant motion.

There’s more than one way to use a 3D printer to create a zoetrope, and we doubt we would have ever thought of this one that squashes four dimensions into three.

Continue reading “3D Zoetrope Uses Illusion To Double The Frames” →

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.

Continue reading “Flipbook Automation Saves Your Thumb” →

Time-Stretching Zoetrope Animation Runs Longer Than It Should

August 27, 2018 by Steven Dufresne 11 Comments

3D printers have long since made it easy for anyone to make 3-dimensional zoetropes but did you know you can take advantage of a 4th dimension by stretching time? Previously the duration of a zoetrope animation would be however long it took for the platform to rotate once. To make it more interesting to watch for longer, you filled out the scene by creating concentric rings of animations. [Kevin Holmes], [Charlie Round-Turner], and [Johnathan Scoon] have instead come up with a way to make their animations last for multiple rotations, longer than three in one example. If you’re not at all familiar with these 3D zoetropes, you might want to check out this simpler version first.

Their project name is 4-Mation but they call the time-stretching technique, animation multiplexing. One way to implement it is to use one long spiral beginning in the center and ending on the platform’s periphery. It’s the spiral path which make the animation last longer.

In their Fish eating Fish animation, the spiral is of a small fish which exits a clam at the center and gets progressively larger as it spirals outward until it swallows another fish located in a ring at the periphery. Of course when you look at it with a properly timed strobe light, there is no spiral. Instead, it appears as though a bunch of fish move more-or-less radially out from the center. The second video embedded below walks through the animation step-by-step, making it easier to follow the intricacies of what’s going on.

Other features include built-in strobe lighting and both manual and phone app control. This project is a product for a kickstarter campaign and so normally, details of the electronics would be absent. But clearly [Kevin] is familiar with Hackaday and sent in some additional info which you can find below, along with the videos.

Continue reading “Time-Stretching Zoetrope Animation Runs Longer Than It Should” →

Digital Zoetrope Powered By Pi

March 11, 2016 by Jenny List 2 Comments

A zoetrope is a charming piece of Victoriana, a device that gives the sensation of a moving image by exposing its successive frames through slits in a rotating drum. [Brian Corteil] however is not content with a mere 19th century parlour amusement, he’s connected twelve OLED displays to a Raspberry Pi and mounted them on a circular platform with a rotary encoder to make a fully digital zoetrope.

Connecting 12 SPI devices to the Pi was always going to be something of a challenge, because only two CS lines are provided. [Brian] has a rather elegant solution to this problem, he’s daisy-chained his displays to form a shift register in which each image is passed to the next display on a rotational increment.

His resulting zoetrope sits on a laser-cut frame which rotates over an encoder disc which looks to be made from printed paper. It is still something of a work in progress, but he has plans to record video on the Pi camera for immediate playback on his creation. You can take a look at his code for the zoetrope on GitHub.

This isn’t the first zoetrope we’ve covered here at Hackaday, or even the first digital one. We’ve seen a couple of 3d-printed ones, and one featuring laser-cut images captured with a Kinect. But it’s a good piece of work, and has the promise of more to come if his camera plans come to fruition. Continue reading “Digital Zoetrope Powered By Pi” →

Animate Your Artichoke With A Lathe And Camera

January 14, 2015 by Sarah Petkus 13 Comments

Spirals, fractals, and even bone length proportions whisper of a consistent ratio woven into the universe. Math is hidden in the fabric of things, and when this fact is observed in art, magic happens. Professor, artist, and inventor [John Edmark] draws inspiration from geometric patterns found in nature and builds sculptures using the golden ratio as a standard for design. In this project, he expresses these characteristics through animated biomorphic zoetropes.

[John] modeled several 3D sculptures in Rhino containing similar geometric properties to those found in pinecones and palm tree fronds. As the segments grow from those objects in nature, they do so in approximately 137.5 degree intervals. This spacing produces a particular spiral appearance which [John] was aiming to recreate. To do so, he used a Python script which calculated a web of quads stretched over the surface of a sphere. From each of the divisions, stalk-like protrusions extend from the top center outward. Once these figures were 3D printed, they were mounted one at a time to the center of a spinning base and set to rotate at 550 RPM. A camera then films the shape as it’s in motion at a 1/2000 sec frame rate which captures stills of the object in just the right set of positions to produce the illusion that the tendrils are blooming from the top and pouring down the sides. The same effect could also be achieved with a strobe light instead of a camera.

[John] has more information on his instructables page. He also provides a video of this trick working with an actual artichoke; one of the living examples of the golden ratio which this project was inspired by. Thank you, [Charlie Nordstrom] for helping him document these awesome sculptures and for telling us about them!

Continue reading “Animate Your Artichoke With A Lathe And Camera” →

POV Display Does It On The Cheap

July 23, 2014 by Adam Fabio 15 Comments

[Sholto] hacked together this ultra low-budget spinning display. He calls it a zoetrope, but we think it’s actually an LED based Persistence Of Vision (POV) affair. We’ve seen plenty of POV devices in the past, but this one proves that a hack doesn’t have to be expensive or pretty to work!

The major parts of the POV display were things that [Sholto] had lying around. A couple of candy tins, a simple brushed hobby motor, an Arduino Pro Mini, 7 green LEDs, and an old hall effect sensor were all that were required. Fancy displays might use commercial slip rings to transfer power, but [Sholto] made it work on the cheap!

The two tins provide a base for the display and the negative supply for the Arduino. The tins are soldered together and insulated from the motor, which is hot glued into the lower tin. A paper clip contacts the inside of the lid, making the entire assembly a slip ring for the negative side of the Arduino’s power supply. Some copper braid rubbing on the motor’s metal case forms the positive side.

[Sholto] chose his resistors to slightly overdrive his green LEDs. This makes the display appear brighter in POV use. During normal operation, the LEDs won’t be driven long enough to cause damage. If the software locks up with LEDs on though, all bets are off!

[Sholto] includes software for a pretty darn cool looking “saw wave” demo, and a simple numeric display. With a bit more work this could make a pretty cool POV clock, at least for as long as the motor brushes hold up!

Continue reading “POV Display Does It On The Cheap” →