OHS 2013 Highlights: NeoLucida

NeoLucida was the subject of one of the best presentations and demos at the 2013 Open Hardware Summit.

The NeoLucida is a drawing aid that allows you to trace what you see.  It’s the first portable, authentic camera lucida to be manufactured in nearly a century. We love camera lucidas, and we think they can help people understand art history in provocative new ways.

The NeoLucida is was launched in a wildly successful kickstarter campaign to make a modern version of a camera lucida available to a new generation of artists. It’s not a complicated device, but it is an extremely specialized one, and niche products like it are a place where open source hardware and crowdfunding can come together incredibly successfully. They were able to bring the cost of owning a camera lucida into the realm of possibility for artists who can’t afford antiques. By publishing how the device works and how they make it, they have increased understanding both of the device itself and of historical works of art made using it.

It was exciting to try out a NeoLucida during the demo session at the summit, especially after hearing about its history.

OHS 2013 Highlights: DropBot

DropBot is an open source Digital Microfluidic (DMF) automation system that was presented at the 2013 Open Hardware Summit by Ryan Fobel of Wheeler Microfluidics Laboratory at the University of Toronto.

In DMF, discrete fluidic droplets are manipulated on the surface of an array of electrodes coated with a hydrophobic insulator.

It extremely exciting to see the sciences embracing open hardware in new ways.

Open Medical Hardware: The Open Stent

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The stent pictured above is an example of an Open Stent from NDC, makers of nitinol materials and devices, particularly for medical applications. In their introduction to the project, they write:

The first problem that we encounter when developing useful and practical educational resources for stent design is that every design we might want to use as an example is proprietary! That leaves us without much to talk about… So to solve this problem, the first step was to create a design to use as an example. The Open Stent is designed to be completely generic, but also realistic, and relatively easy to modify and extend to be useful for whatever purpose a designer intends.

In addition to publishing their draft of Open Stent Design, which they call “a practical guide and resource for design and analysis of a generic Nitinol stent,” NDC has provided extensive calculation tools and CAD files as well, to help others evaluate and create derivatives of the design.

The project is a fascinating open source hardware use case, where creating an open design provides a platform for education and discussion where none existed before.  It’s also very exciting to recognize this as an early example of open source hardware in the field of medical devices— one of the places where open hardware can potentially make a very big difference in the world.

Marking Klein Bottles with the Eggbot

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We were lucky enough to have a visit from Cliff Stoll, geek celebrity and proprietor of Acme Klein Bottle. Acme is the finest source of Klein bottles on the internet.

Cliff came with an esoteric dilemma: how to engrave a glass Klein bottle. Acme Klein bottles are blown from borosilicate (Pyrex) glass, which has a low coefficient of thermal expansion, which means that the usual way of engraving a curved glass surface—laser engraving—doesn’t actually work.  With more common types of glass, you can use a laser engraver to etch anything you want into the surface. But with Pyrex, the surface simply melts unevenly rather than creating the microfractures that give an etched appearance.

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So how would you etch the curved surface of a Klein bottle? It turns out, to our surprise, that it is remarkably easy to do it with an Ostrich Eggbot fitted with a diamond engraver attachment.

There was one complication, which is that a Klein bottle is a funny shaped object! In order to fixture the Klein bottle in the Eggbot, we made a couple of extra large couplers—much larger than the tiny pads normally used to hold the ends of an egg—with EVA foam rubber pads on their surfaces. The extra large couplers held the Klein bottle securely for rotation.

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We did some initial tests with Sharpie and a medium sized Klein bottle to make sure our fixturing worked well.

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And then we hooked up an engraver for a real test.

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Here’s what the Klein bottle looked like after engraving. Not being particularly creative, we etched the word “KLEIN” into the side.  Because the Klein bottle is made from thick borosilicate glass, it takes engraving remarkably well. It is a much more sturdy object than the fragile Christmas ornaments that we have engraved in the past.

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While we can’t imagine that it is a major market segment, the Eggbot seems to be ideal for working with Klein bottles (insomuch as anything can be perfect for working with a closed, non-orientable, boundary-free manifold). But regardless, it’s quite wonderful to find an unexpected application like this, where our little robot can solve a real-world problem that we had never even considered.

The Mug Marker

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Don McRae recently stopped by our shop last week to show off his homebrew CNC project, the “Mug Marker” — a wonderful little cardboard robot that can draw on mugs.

Much like the Mug Plotter on Instructables, it uses the same EBB controller board and stepper motors as the Eggbot, but with linear motion for the pen instead of rotation. However, unlike that version, Don has incorporated the same winch-drive mechanism that we use on the WaterColorBot to provide motion for the linear axis– meaning that it can go fast or slow, with very good accuracy.

Don laser cut the large white winch on the back of the machine from acrylic. It controls a string that pulls the pen carriage back and forth as it rides on a pair of rods:

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The pen holder itself slides into some additional bearings, and has a small protrusion on the back that rests on the servo horn, allowing it to be lifted up or lowered down.  Like the Eggbot’s pen-lift mechanism, this mechanism only (actively) lifts the pen, which means that it can ride over uneven surfaces, or plot on mugs with variable diameter.

 

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Underneath the pen carriage, the opening of the mug fits onto a three-jaw coupler on the motor shaft, and the base of the mug is held against a rubber faced spring loaded plunger. Small copper tubes are used as bushings to allow the coupler pieces to rotate inward or outward to allow mugs of differing diameters to fit on. A little silicone on the surface of each of the three parts provides a gripping surface, and the upcurved lip keeps the mug from sliding too far.

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Looking down through the pen carriage, you can see the mug below held in the coupler.

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The chassis of the machine is made from cardboard, either hand or laser cut to slot together, and held together very cleverly with pins. The whole machine is put together from a combination of off the shelf parts and found materials, many of which are laser cut for the correct shape. For software, Don uses the Eggbot Inkscape extensions with very reproducible results.

Thanks to Don for bringing it by and letting us take pictures!