How a Real 3D Display Works

There’s a new display technique that’s making the blog rounds, and like anything that seems like its torn from [George Lucas]’ cutting room floor, it’s getting a lot of attention. It’s a device that can display voxels in midair, forming low-resolution three-dimensional patterns without any screen, any fog machine, or any reflective medium. It’s really the closest thing to the projectors in a holodeck we’ve seen yet, leading a few people to ask how it’s done.

This isn’t the first time we’ve seen something like this. A few years ago. a similar 3D display technology was demonstrated that used a green laser to display tens of thousands of voxels in a display medium. The same company used this technology to draw white voxels in air, without a smoke machine or anything else for the laser beam to reflect off of. We couldn’t grasp how this worked at the time, but with a little bit of research we can find the relevant documentation.

A system like this was first published in 2006, built upon earlier work that only displayed pixels on a 2D plane. The device worked by taking an infrared Nd:YAG laser, and focusing the beam to an extremely small point. At that point, the atmosphere heats up enough to turn into plasma and turns into a bright, if temporary, point of light. With the laser pulsing several hundred times a second, a picture can be built up with these small plasma bursts.

2-fig2

Moving a ball of plasma around in 2D space is rather easy; all you need are a few mirrors. To get a third dimension to projected 3D images, a lens mounted on a linear rail moves back and forth changing the focal length of the optics setup. It’s an extremely impressive optical setup, but simple enough to get the jist of.

Having a device that projects images with balls of plasma leads to another question: how safe is this thing? There’s no mention of how powerful the laser used in this device is, but in every picture of this projector, people are wearing goggles. In the videos – one is available below – there is something that is obviously missing once you notice it: sound. This projector is creating tiny balls of expanding air hundreds of times per second. We don’t know what it sounds like – or if you can hear it at all – but a constant buzz would limit its application as an advertising medium.

As with any state-of-the-art project where we kinda know how it works, there’s a good chance someone with experience in optics could put something like this together. A normal green laser pointer in a water medium would be much safer than an IR YAG laser, but other than that the door is wide open for a replication of this project.

Thanks [Sean] for sending this in.

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Don’t You Just Love Comic Sans?

Trick question! Of course you do, everyone loves Comic Sans! It’s only like the best font in the history of the internet! Why would you ever use anything else?

Oh! Is it because you feel like writing your novella on a computer is cheating? You wish you could use Comic Sans on your classic Sears-branded Brother Charger 11 typewriter from the 70’s? Don’t worry, we’ve got you covered.

Jokes aside, this is actually a pretty clever hack. He’s modified a typewriter to use custom letters which he has laser cut out of acrylic and super glued to the strikers of the typewriter. Continue reading “Don’t You Just Love Comic Sans?”

A Folding Laser Cutter

Want a laser cutter, but don’t have the space for one? How about a portable machine to engrave and cut wood and plastics? A folding laser cutter solves these problems, and that’s exactly what Red Ant Lasers was showing off last weekend at Maker Faire.

Inside the team’s Origami laser cutter is a 40 Watt CO2 tube, shooting its beam along an entirely enclosed beam path. The beam travels through the body of the machine, out into the folding arm of the machine, and down to whatever material you’ve placed the Origami on. It’s a 40 Watt laser so it will cut plywood and plastics, and as shown in the video above, does a fine job at engraving plywood.

This is a Class 4 laser device operating without any safety glass, but from the short time I spent with the Red Ant team, this is a reasonably safe device. You will need safety glasses if you’re within five feet, but after that, everything (according to OSHA, I think) is safe and not dangerous. Either way, it’s a tool just like a table saw. You don’t see commentors on the Internet complaining about how a spinning metal blade is dangerous all the time, do you?

The Red Ant guys are currently running a Kickstarter for their project, with a complete unit going for $4200. It’s pricier than a lot of other lasers, but not being constrained by the size of a laser cutters enclosure does open up a few interesting possibilities. You could conceivably cut a 4×8 sheet of plywood with this thing, and exceptionally large engravings start looking easy when you have a portable laser cutter.

Vector Laser Projector is a Lesson in Design Processes

After two years of EE coursework, [Joshua Bateman] and [Adam Catley] were looking for a fun summer project. Instead of limping along with the resources they could put together themselves, they managed to get their school — Bristol University — to foot the bill!

Now Uni’s aren’t in the habit of just forking over funding for no reason, and we thing that’s why the two did such a great job of documenting their work. We’re used to seeing blogs devoted to one project, but this one has a vast portfolio of every piece of work that went into the build. Before any assembly started they drew out design diagrams to form the specification, laid out the circuit and the board artwork, and even worked out how the software would function in order to make sure the hardware met all their needs.

When the parts arrived the work of hand-populating the surface mount boards began. This is reflected in the fast-motion video they recorded including this clip which features a 176 pin LQFP. The driver board is a shield for a Raspberry Pi which drives the Galvanometers responsible for the X and Y movements of the mirror.

The video below shows off their success and the blog makes a great resource to point to when applying for work once a freshly minted diploma is in hand.

What do you think the next step should be? We’d advocate for a trip to crazy-town like this RGB laser projector we saw several years ago. Of course the same classic vector games we saw on Thursday would be equally awesome without alerting this hardware at all.

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Laser Engraved Business Cards with LEDs

Plexiglass-LED-Lit-Business-Card-1

Regular paper business cards are boring. They are flimsy and easily forgettable for the most part, and when stacked together or thrown in a pile, it’s hard to locate a specific one; like trying to find a needle in a haystack. Plastic cards aren’t much better either because they still fall into that ‘who cares’ category. But plexiglas business cards with laser cut etchings beautifully lit up by an LED?! Yes please.

The design was developed by Romanian engraving company called Gravez Dotro who fixed the problem of simply glancing at a business card, putting it in a wallet, and causally forgetting about it later, never to contact the person that gave it out. If someone hands away one of these though, the receiver is definitely going to remember it. The solution isn’t that high-tech and just about anyone with access to a laser cutter can make their own. It will be interesting to see what people come up with. If you feel like creating one, be sure to send us pictures. We would love to see them. Video of the design comes up after the break.

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Upgrade That Cheap-o Laser Cutter!

Upgrading a Laser Cutter with RAMPS

Laser cutters are perhaps one of the most useful tools in a hackerspace’s arsenal of tools, rivaled only by 3D printers and CNC mills. The problem is they’re quite expensive — unless you get one of the cheap little ones from China that is! Unfortunately, you get what you pay for. Lucky for us though they aren’t that hard to upgrade!

[Dan Beaven] just finished upgrading his 40W CO2 laser to use an Arduino Mega 2560 and RAMPS 1.4 — wanting to share his knowledge he’s posted a guide to help others do the same. The upgrade itself isn’t that difficult, although can be a bit messy for wiring. In the future [Dan] hopes to design a PCB with all the connectors so it’s as simple as plugging it into the RAMPS board.

To control the laser he’s using firmware from the Lansing Makers Network (GitHub) designed for use with marlin electronics. He’s modified it a bit for his own purposes (Google Drive) including a low output LASAR activation signal.The cool thing with setting up your laser with this hardware is that you can use a laser output plugin right in Inkscape!

A DIY Geomagnetic Observatory

Magnetometer observatory

[Dr. Fortin] teaches physics at a French High School, and to get his students interested in the natural world around them, he built a geomagnetic observatory, able to tell his students if they have a chance at seeing an aurora, or if a large truck just drove by.

We’ve seen this sort of device before, and the basic construction is extremely similar – a laser shines on a mirror attached to magnets. When a change occurs in the local magnetic field, the mirror rotates slightly and the laser beam is deflected. Older versions have used photoresistors, but [the doctor] is shining his laser on a piece of paper and logging everything with a webcam and a bit of OpenCV.

The design is a huge improvement over earlier DIY attempts at measuring the local magnetic field, if only because the baseline between the webcam and mirror are so long. When set up in his house, the magnetometer can detect cars parked in front of his building, but the data he’s collecting (French, but it’s just a bunch of graphs) is comparable to the official Russian magnetic field data.