Engineering By Design: Embedded Sensors Make 3D Prints Come Alive

A locomotive engineer gets a bionic hand, cow bones are pulverized to 3D-print new faces, and new sensing tech make action figures come alive.

Get a Grip

Former locomotive engineer, Danny Letain, lost part of his left arm in a workplace accident 36 years ago. He has since used a prosthesis that uses straps to move the limb mechanically.

That is until Letain started working with Simon Fraser University researchers to design a new, much more intuitive control system on what may be one of the world's most advanced bionic hands. 

Using a Bebionic3 robotic arm on loan from Steeper Prosthetics, the new system consists of an armband of pressure sensors embedded in the prosthetic socket. These track movements in Letain's remaining muscles as he performs intuitive actions, like grabbing a bottle. Computer algorithms then map the sensor data to decode his intentions and move the prosthesis. 

The true test will come when Letain competes at the inaugural Cybathlon in October. Dubbed the cyborg Olympics, it's an international competition for people with disabilities using robotic technology. 

Really, all Letain wanted was to wiggle his fingers again. With this new technology, he will certainly do much more than that.

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3D Printing New Faces With Pulverized Cow Bones

Nearly 200,000 people need bones replaced in their head or face, every year. In the past, the best treatment was to have surgeons remove a part of your leg, cut it into the general shape needed and implant it. The procedure is not only hard on your leg, but it’s often difficult to shape a relatively straight fibula to match the subtle curves of your face.

But could it be possible to mix pulverized natural bone with some special man-made plastic and create a much more sculpted shape with a 3D printer?

A team of researchers at Johns Hopkins University believes so, and they have set out to make a composite material that would combine the strength and printability of plastic with the biological "information" contained in natural bone.

They took PCL, an FDA-approved biodegradable polyester, and mixed it with bone powder made from pulverized cow knees.

The team is still looking for the right mix of PCL and bone that is sturdy and encourages bone growth. But the team did recently patch relatively large holes in mice skulls. And they not only lived, but new bone started to grow.  

In their next phase, the researchers will not only move on to thicker bones that need replacing, but they'll also switch to pulverized human bones.

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Getting More Action Out of 3D-Printed Figures

Disney Research has partnered with some elite minds to embed piezoresistive sensing elements into flexible 3D-printed objects.

What does that mean? It means that 3D printed objects could be use as gaming controllers. It means that action figures could respond to each bend and break with a corresponding baam, or slash, or blop. It even means, that you could animate a new 3D character in CAD, print it, embedded these sensors, and then animate the object by capturing physical twists and turns.

It’s all possible because the researchers developed a novel optimization-based algorithm for the design and development of customized, deformable input devices that continuously sense their deformation.

So how does it work? The designer first creates the bends and breaks and roughly indicate where to place internal sensors. The optimization algorithm then refines the sensor placement to maximize accuracy. They then print the design, insert the piezoresistive wires in-between the 3D-printed body parts, and then calibrate it using motion capture. 

Now, fun with action figure sound effects

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This is Engineering By Design. 

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