This Animatronic Mouth Mimics Speech With Servos

April 30, 2020 by Dan Maloney 12 Comments

Of the 43 muscles that comprise the human face, only a few are actually important to speaking. And yet replicating the movements of the mouth by mechanical means always seems to end up only partly convincing. Servos and linkages can only approximate the complex motions the lips, cheeks, jaw, and tongue are capable of. Still, there are animatronics out there that make a good go at the job, of which this somewhat creepy mechanical mouth is a fine example.

Why exactly [Will Cogley] felt the need to build a mechanical maw with terrifying and fairly realistic fangs is anyone’s guess. Recalling his lifelike disembodied animatronic heart build, it just seems like he pursues these builds for the challenge of it all. But if you thought the linkages of the heart were complex, wait till you see what’s needed to make this mouth move realistically. [Will] has stuffed this pie hole with nine servos, all working together to move the jaw up and down, push and pull the corners of the mouth, raise and lower the lips, and bounce the tongue around.

It all seems very complex, but [Will] explains that he actually simplified the mechanical design to concentrate more on the software side, which is a text-to-speech movement translator. Text input is translated to phonemes, each of which corresponds to a mouth shape that the servos can create. It’s pretty realistic although somewhat disturbing, especially when the mouth is placed in an otherwise cuddly stuffed bear that serenades you from the nightstand; check out the second video below for that.

[Will] has been doing a bang-up job on animatronics lately, from 3D-printed eyeballs to dexterous mechatronic hands. We’re looking forward to whatever he comes up with next — we think.

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3D Printering: Will A Resin Printer Retire Your Filament-based One?

April 30, 2020 by Donald Papp 25 Comments

Adding a resin printer to one’s workbench has never looked so attractive, nor been so affordable. Complex shapes with effortlessly great detail and surface finish? Yes, please! Well, photos make the results look effortless, anyway. Since filament-based printers using fused deposition modeling (FDM) get solid “could be better” ratings when it comes to surface finish and small detail resolution, will a trusty FDM printer end up retired if one buys a resin printer?

The short answer is this: for users who already use FDM, a resin-based stereolithography (SLA) printer is not likely to take over. What is more likely to happen is that the filament printer continues to do the same jobs it is good at, while the resin printer opens some wonderful new doors. This is partly because those great SLA prints will come at a cost that may not always justify the extra work.

Let’s go through what makes SLA good, what it needs in return, and how it does and doesn’t fit in with FDM.

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Giving Surfaces Their Own Antiviral Coating To Fight Infection

April 30, 2020 by Maya Posch 15 Comments

The use of disinfectants is not a new thing, but a major disadvantage with most common disinfectants is that they are only effective in the short term. After applying bleach, alcohol or other disinfectant to the surface, the disinfectant’s effect quickly fades as the liquid evaporates. Ideally the disinfectant would remain on the surface, ready to disinfect when needed.

According to researchers at the Hong Kong University of Science and Technology (HKUST), the solution may lie in a heat-sensitive coating that releases disinfectant when it’s needed. This Multilevel Antimicrobial Polymer (MAP-1) can remain effective for as long as 90 days, depending on how often the surface is touched or otherwise used.

MAP-1 consists out of polymer strands of a material that prevents viruses and bacteria from attaching to its surface, while disrupting its outside surface. Effectively this has the potential to inactivate (kill) most viruses and harmful bacteria that come into contact with it.

MAP-1 is currently being deployed in Hong Kong, where public places such as schools, malls and sport facilities have had the coating applied. It costs between US $2,600 and US $50,000 to treat an area, which is not cheap, but would be cheaper than shutting down such a facility for regular surface disinfecting.

Although it still has to be determined that MAP-1 is as effective as hoped, it is another example of an antimicrobial surface, a material that is designed to be as incompatible with sustaining viruses and bacteria as possible. In the past copper and its alloys have been commonly used for this purpose, but a polymer coating is obviously more versatile. From the point of view of today’s pandemic, making surfaces incapable of hosting viruses definitely can be regarded as highly necessary.

(Pictured: a MAP-1 coating on a surface, courtesy of HKUST)

Ultrasonic Sound Gun Precisely Aims Your Music

April 30, 2020 by Moritz v. Sivers 25 Comments

When listening to music you sometimes cannot avoid the situation where other people get annoyed because they feel it disrupts their important doings or they do not share your taste in avant-garde doom metal. Of course one could just use headphones. But a hackier way would be to build a parametric speaker that focuses soundwaves into a narrow beam like [Shane] did with this ultrasonic sound gun.

As the directivity of a soundwave depends on the size of the source and its frequency, a directed beam can practically only be achieved with ultrasound. Even though we are not able to perceive frequencies above ~20 kHz, the nonlinear properties of air make it possible to hear the audio modulated onto an ultrasonic carrier signal. For his sound gun [Shane] was inspired by another parametric speaker project. It took him some time to get the 555 timer circuit oscillating at the right frequency and he fried a cheap Bluetooth audio module while trying to increase the output volume but in the end, he managed to get everything working. As the project name suggests, he also 3D printed a gun-shaped enclosure. The video below shows that the sound from the gun behaves really similar to a beam of light and can, for example, be bounced off other objects.

If you are looking for other inspiration there is a whole list of cool ultrasonic projects from distance sensors to acoustic levitation.

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