Hackaday Podcast 126: Cable 3D-Scanner, Tesla Charger Robot, Ultrasonic Anemometer, And A Zoetrope

Hackaday editors Elliot Williams and Mike Szczys dive into a week of exceptional hacks. Tip-top of the list has to be the precision measuring instrument that uses a cable spooling mechanism. There’s news that the Starlink base station firmware has been dumped and includes interesting things like geofencing for the developer modes. We saw a garage robot that will plug in your electric vehicle if you’re the forgetful sort. And we close up by talking about heavier-than-air helium airships and China’s Mars rover.

Take a look at the links below if you want to follow along, and as always, tell us what you think about this episode in the comments!

Direct download (55 MB or so.)

Places to follow Hackaday podcasts:

Continue reading “Hackaday Podcast 126: Cable 3D-Scanner, Tesla Charger Robot, Ultrasonic Anemometer, And A Zoetrope”

3D Zoetrope Uses Illusion To Double The Frames

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”

4-Mation Fish eats fish

Time-Stretching Zoetrope Animation Runs Longer Than It Should

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.

4-Mation Fish eats Fish zoetropeTheir 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”

3D Printed Zoetrope Sculpture Squashes 4 Dimensions Into 3

This fascinating project manages to be both something new and something old done in a new way. Artist [Akinori Goto] has used 3D printing to create a sort of frameless zoetrope. It consists of a short animation of a human figure, but the 3D movements of that figure through time are “smeared” across a circular zone – instead of the movements of the figure being captured as individual figures or frames, they are combined into a single object, in a way squashing 4 dimensions into 3.

zoetrope-1“Slices” of that object, when illuminated by a thin shaft of light, reveal the figure’s pose at a particular moment in time. When the object is spun while illuminated in this way, the figure appears to be animated in a manner very similar to a zoetrope.

There are two versions from [Akinori Goto] that we were able to find. The one shown above is a human figure walking, but there is a more recent and more ambitious version showing a dancer in motion, embedded below.

Since a thin ray of light is used to illuminate a single slice of the sculpture at a time, it’s also possible to use multiple points of illumination – or even move them – for different visual effects. Check out the videos below to see these in action.

Continue reading “3D Printed Zoetrope Sculpture Squashes 4 Dimensions Into 3”

Digital Zoetrope Powered By Pi

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”

Before Film There Were Zoetropes. Now We Have 3D Printed Zoetropes!

Reddit user [eyelandarts] has produced a rather unique 3D printing project. A 3D printed Zoetrope.

You see, a zoetrope was a device that created an animation effect that pre-dates film technology. It would create the illusion of motion much like a flip book does, but with a spinning cylindrical wall with slots cut into it. As the cylinder spins, you catch a glimpse of the animation through the slots. But, it’s just a 2-dimensional animation — what if you replaced it with an ever changing 3D model?

It’s actually been done before. A long time ago in fact. In 1887, [Etienne-Jules Marey] created a large zoetrope to animate plaster models of a bird in flight. Fast forward to today, and [eyelandarts] has 3D printed something similar — but ditched the cylindrical wall. Instead, a strobe light is used to see the animation!

The end result is quite awesome if we do say so our-selves. For another fun take on Zoetropes — how about a digital one made out of tiny LCD screens?

Siezure-warning… there’s a very flash-tastic demo gif embedded after the break if you’re brave enough to view such a thing.

Continue reading “Before Film There Were Zoetropes. Now We Have 3D Printed Zoetropes!”

Digital Zoetrope Uses 18 LCD Displays

[Jasper] sent in a project he, [Quinten], and [Mr. Stock] have been working on for a while. It’s called the Pristitrope and brings the classic 19th centrury paper-based animation device into the 21st century with 18 LCD displays.

The lazy suzan portion of the build was fabricated out of plywood cut on a CNC router and fastened together with the help of a slip ring to transfer power between the stationary and spinning portions of the device. For the electronic part of the build, eighteen LCD displays were connected together on a data bus with each display independently addressable by a microcontroller.

One really interesting feature of the Pristitrope is its ability to detect if it is currently rotating clockwise or counterclockwise. While [Quinten]’s video doesn’t show off the full possibilities of this feature, the spin sensor makes it possible to always have an animation played in the right direction regardless of how the Pristitrope is spun.

Continue reading “Digital Zoetrope Uses 18 LCD Displays”