[Denha's] been building marble machines for years and decided to look a back on some of his favorite marble-based builds  (translated). There’s a slew of them, as well as some thoughts about each. Our favorite part is the digital simulations of the projects. For instance, the image above shows a flip-flop marble machine that was built in a physics simulator. This makes it a lot easier to plan for the physical build as it will tell you exact dimensions before you cut your first piece of material. Both of these images were pulled from videos which can be seen after the break. But this isn’t the most hard-core of pre-build planning. SolidWorks, a CAD suite that is most often used to design 3D models for precision machining, has also been used to model the more intricate machines.

[via Make]

[Ameres Valentin] writes in to let us know about his DIY particle accelerator model. The model, made mostly out of old computer stuff, mimics a linear high-energy particle accelerator which use drift tubes to toss particles around. Drift tubes work by first attracting a particle (in this case, ball bearing) until it crosses a charged plate (in this case, coil), then flipping the charge polarity and repelling the particle.  In this case the accelerators function more like a multiple coil gun, as they can’t exactly push the bearing away. Regardless of the specifics the model is an excellent visual aid.

As the bearing rolls along the rails of the CD spindle it shorts bits of foil tape placed just ahead of the magnets. This (appears) to flip a relay that switches on the magnet. Once the magnet coil is energized it pulls the bearing towards its center, accelerating it. The foil stops just before the point where the magnet would pull back the bearing. We are not sure if [Ameres] is using any trickery to get the magnets to individually power, as schematics are not available. The circuit should be simple enough to figure out with a couple relays. In the video [Ameres] adds a lamp to the coils to display when they are powered. Nice work! This could make a fun distraction desk accessory, better than those clicky Newton’s cradles.

Check out [Ameres]‘ site for a video of the model in action.

Here is a bare-bones multitouch table setup. We looked in on [Seth Sandler's] multitouch work a few years ago when he completed the MTmini build. He’s scaling up the size a bit with the MTbiggie, and showing you how easy it is to put together. The demo rig seen above is just a couple of chairs, a sheet of acrylic, a mirror, a projector, a computer, and a diy infrared webcam.

The rig uses ambient infrared light to detect the outlines of your fingers when they touch the acrylic surface. A webcam with an exposed camera film filter feeds an image of the infrared light received below the surface to the computer. The incoming video is processed using Community Core Vision, where each individual point is isolated and mapped. Once the data is available the sky’s the limit on what you can develop. [Seth's] demo packages include a mouse driver, some physics applications, an Angry Birds implementation, and a few others. See for yourself in the video after the break.

Since the Kinect has become so popular among hackers, [Brad Simpson] over at IDEO Labs finally purchased one for their office and immediately got to tinkering. In about 2-3 hours time, he put together a pretty cool physics demo showing off some of the Kinect’s abilities.

Rather than using rough skeleton measurements like most hacks we have seen, he paid careful attention to the software side of things. Starting off using the Kinect’s full resolution (something not everybody does) [Brad] took the data and manipulated it quite a bit before creating the video embedded below. Skeleton data was collected and run through several iterations of a smoothing algorithm to substantially reduce the noise surrounding the resulting outline.

The final product is quite a bit different than the Kinect videos we are used to seeing, and it drastically improves how the user is able to interact with virtual objects added to the environment. As you may have noticed, the blocks that were added to the video never rarely penetrate the outline of the individual in the movie. This isn’t due to some sort of digital trickery – [Brad] was able to prevent the intersection of different objects via his tweaking of the Kinect data feed.

We’re not sure how much computing power this whole setup requires, but the code is available from their Google Code repository, so we hope to see other projects refined by utilizing the techniques shown off here.

[via KinectHacks]

The space elevator may be a very real possibility within our lifetimes. Previously the stuff of science fiction novels, scientists and engineers around the world will continue their discussion at a conference in Japan this November. The space elevator’s basic design would include a cable that is anchored to the Earth’s surface, and on the other end, tens of thousands of kilometers away, a counterweight for balance. The space elevator could be used to solve many different problems, from nuclear waste disposal to powering homes with solar panels.

The technology driving the development of the space elevator is the carbon nanotube. Its lightweight properties and tensile strength, over 180 times stronger than steel cable, make it the ideal cable for the space elevator. Currently there are several logistical problems, which range from designing a carbon nanotube strong enough to support the elevator to finding an ideal site to design and build the elevator, which would require international consensus and input. Several organizations are working on space elevator designs, and NASA is holding a $4 million Space Elevator Challenge to encourage designs.

[via MetaFilter]