January has drawn to a close, and for many of you that means: “Oh no! Less than two weeks’ time until Valentine’s day.” But for us here at Hackaday, it means heart-themed blinky projects. Hooray!
[Dmitry Grinberg] has weighed in with his version of the classic heart-shaped LED ring. It’s hard to beat the BOM on this one: just a microcontroller, five resistors, and twenty LEDs. The rest is code, and optionally putting the name of your beloved into the copper layer. Everything is there for you to download.
How much access do you have to a 3D printer? What would you do if you had weeks of time on your hands and a couple spools of filament lying around? Perhaps you would make a two second stop-motion animation called Bears on Stairs.
An in-house development by London’s DBLG — a creative design studio — shows a smooth animation of a bear — well — climbing stairs, which at first glance appears animated. In reality, 50 printed sculptures each show an instance of the bear’s looping ascent. The entire process took four weeks of printing, sculpture trimming, and the special diligence that comes with making a stop-motion film.
The stargate in 2001 is that long, trippy bit where our protagonist Dave “I’m sorry Dave” Bowman gets pulled through space and time into some kind of alternate universe and is reborn as the star child. (Right, the plot got a little bit bizarre.) But the stargate sequence, along with the rest of the visual effects for the film, won them an Academy Award.
Other examples of slit scan animations you’ll recognize include the opening credits for Doctor Who and the warp-drive effect in Star Trek: TNG.
Remember those flipbooks you doodled into your history textbooks while you waited for the lunch bell? [Maric] takes the general principles of flipbooks and turns them on their head, giving our brain a whirl in the process. By splicing multiple frames into one image, he can bring animations to life onto a single page.
The technique is simple, but yields impressive results. By overlaying a pattern of vertical black bars onto his image, only a small fraction of the image is visible at any given point. The gaps in the pattern belong to a single frame from the animation. As [Maric] slides the pattern over the image, subsequent frames are revealed to our eyes, and our brain fills in the rest.
A closer look reveals more detail about the constraints imposed on these animations. In this case, the number of frames per animation loop is given by the widths in the transparency pattern. Specifically, it is the number of transparent slits that could fit, side-by-side, within an adjacent black rectangle.
The trick that makes this demonstration work so nicely is that the animated clips finish where they start, resulting in a clean, continuous illusion.
Don’t believe what you see? [Maric] has linked the pattern and images on his video so you can try them for yourself. Give them a go, and let us know what you think in the comments.
Computer animation is a task both delicate and tedious, requiring the manipulation of a computer model into a series of poses over time saved as keyframes, further refined by adjusting how the computer interpolates between each frame. You need a rig (a kind of digital skeleton) to accurately control that model, and researcher [Alec Jacobson] and his team have developed a hands-on alternative to pushing pixels around.
The skeletal systems of computer animated characters consists of kinematic chains—joints that sprout from a root node out to the smallest extremity. Manipulating those joints usually requires the addition of easy-to-select control curves, which simplify the way joints rotate down the chain. Control curves do some behind-the-curtain math that allows the animator to move a character by grabbing a natural end-node, such as a hand or a foot. Lifting a character’s foot to place it on chair requires manipulating one control curve: grab foot control, move foot. Without these curves, an animator’s work is usually tripled: she has to first rotate the joint where the leg meets the hip, sticking the leg straight out, then rotate the knee back down, then rotate the ankle. A nightmare.
[Alec] and his team’s unique alternative is a system of interchangeable, 3D-printed mechanical pieces used to drive an on-screen character. The effect is that of digital puppetry, but with an eye toward precision. Their device consists of a central controller, joints, splitters, extensions, and endcaps. Joints connected to the controller appear in the 3D environment in real-time as they are assembled, and differences between the real-world rig and the model’s proportions can be adjusted in the software or through plastic extension pieces.
The plastic joints spin in all 3 directions (X,Y,Z), and record measurements via embedded Hall sensors and permanent magnets. Check out the accompanying article here (PDF) for specifics on the articulation device, then hang around after the break for a demonstration video.
Looking for a clever way to build a Phenakistoscope? Maybe you’re more familiar with its other names; Fantoscope, Phantasmascope, or perhaps its close cousin the Zoetrope?
If you’re still scratching your head, that’s okay — they have really weird names. What we’re referring to here is a type of optical illusion that mimics movement by showing a series of still images at an offset interval — this can be achieved by looking through slots, strobing a light (like in this case) or even by the use of mirrors.
This particular Phenakistoscope is a very simple but clever design that makes use of a recycled stepper motor from a printer, a CD as the animation disk, a strip of LED lighting, a few potentiometers and an Arduino to control the strobe. It works by synchronizing the strobe frequency with the motor rotation, resulting in the image in motion effect.
Stick around after the break for a full gallery of the build and a demonstration video.
Halloween receives the bulk of the attention for installation-type hacks, but [Stephen’s] animated elf hack-in-progress provides the perfect example of bringing the Christmas spirit to life.
[Stephen] constructed both the background and the elf’s body from a scrap piece of plywood, drawing and painting everything by hand, and then secured the plywood with a simple 2×4 that serves as a stand. The bulk of the hack is rather simple, and reflects the longstanding technique of traditional cel animation: the non-moving portions are kept stationary and only the moving parts need to change. In this case, [Stephen’s] shortcut is to insert a tablet as the elf’s face.
The tablet is a BlackBerry PlayBook, which moves the eyes around and spouts off a few Santa-related quips while animating the mouth. [Stephen] encountered a problem with the PlayBook’s 5-minute screen timeout function, and had to design a custom application to prevent the tablet from entering sleep mode while it played through the animations. His future plans are to drill a hole through the plywood and expose the tablet’s light sensor to detect when someone walks by, then have the elf spring to life in response. You can see his progress so far in the video below.