Stewart Platform Wields Magic Fingers To Massage Your Scalp

August 4, 2022 by Dan Maloney 13 Comments

Attention Hackaday editors: We on the writing crew hereby formally request budget allocation for installing a Stewart platform head massager on the chair of each workstation in the secret underground writer’s bunker. We think the benefits that will accrue thanks to reduced stress alone will more than justify the modest upfront costs. Thank you for your consideration.

OK, maybe that request is going nowhere, but having been on the receiving end of these strangely relaxing springy scalp stimulators, we can see where [David McDaid] was going with this project. As he clearly states up front, this is a ridiculously over-engineered way to get your scratchies on, but there’s very little not to love about it. Stewart platforms, which can position a surface with six degrees of freedom and range in size from simple ball balancers to full-blown motion simulators, are fascinating devices, and we can’t think of a better way to learn about them than by building one.

Like all Stewart platforms, [David]’s is mechanically simple but kinematically complicated, and he takes great pains to figure out all the math and explain it in an approachable style. The device is mounted with the end-effector pointed down, allowing the intended massagee to insert their noggin into the business end and receive the massage pattern of their choice. Looking at the GIFs below, it’s easy to see why [David] favors the added complexity of a Stewart, which makes interesting patterns like “The Calmer” possible. They’re all intriguing, although the less said about “The Neck Breaker” the better, we’d say.

Hats off (lol) to [David] for this needless complex but entertaining build.

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Dainty Delta Is About As Small As A Robot Can Be

December 28, 2018 by Dan Maloney 8 Comments

There’s something mesmerizing about delta robots. Whether they are used at a stately pace for a 3D-printer or going so fast you can barely see them move in a pick and place machine, the way that three rotary actuators can work together to produce motion in three axes is always a treat to watch. Especially with a delta robot as small as this one.

[KarelK16] says this is one of those “just because I can” projects with no real application. And he appears to have been working on it for a while; the video below is from eight years ago. Regardless, the post is new, and it’s pretty interesting stuff. The tiny ball joints used in the arms are made from jewelry parts; small copper crank arms connect the three upper arms to micro-servos. The manipulator [KarelK16] attached is very clever, too – rather than load down the end of the arms with something heavy, a fourth servo opens an closes a flexible plastic grasper through a Bowden cable. It’s surprisingly nimble, and grasps small objects firmly.

There are certainly bigger deltas – much bigger – and more useful ones, too, but we really like this build. And who knows – perhaps model robotics will join model railroading as a hobby someday. If it does, [KarelK16]’s diminutive delta might be the shape of things to come.

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Friday Hack Chat: Air Hacking

October 24, 2018 by Brian Benchoff 1 Comment

The field of soft robotics sure seems a lot less mature than your standard servo motor and metal framed robot arms. Maybe that’s because building a robot to flex is harder, and maybe it’s because the best methods of constructing soft robotics have only been around for a decade or so. Maybe, though, it’s because it’s hard to control air.

For this week’s Hack Chat, we’re going to be discussing Air Hacking with [Amitabh Shrivastava]. [Amitabh] is a grad student at ITP, NYU studying creative technology, where he makes interactive art, tools for research, and experiments with various materials. Lately he has been developing Programmable-Air, a pneumatic controller for soft robotics. We’ve seen his work at ThiMaker Faire, and it’s an awesome project in this year’s Hackaday Prize.

In this chat we will be talking about DIY soft robotics. Soft robotics is a growing field with a lot of low hanging fruits within grasp of the hobbyist maker. In addition to sharing experience and resources about building your own soft robots, we will talk about actuation! Tune in to see how you can use pneumatics in your next project.

During this week’s Hack Chat, we’ll be discussing:

Pneumatics
Programmable Air
Soft Robotics
Methods of adding pneumatics to your project

You are, of course, encouraged to add your own questions to the discussion. You can do that by leaving a comment on the Air Hacking Hack Chat and we’ll put that in the queue for the Hack Chat discussion.

Our Hack Chats are live community events on the Hackaday.io Hack Chat group messaging. This week we’ll be sitting down on Friday, October 26th, at noon, Pacific time. If time zones got you down, we have a handy time zone converter.

Click that speech bubble to the right, and you’ll be taken directly to the Hack Chat group on Hackaday.io.

You don’t have to wait until Friday; join whenever you want and you can see what the community is talking about.

Mechatronic Hand Mimics Human Anatomy To Achieve Dexterity

October 18, 2018 by Dan Maloney 8 Comments

Behold the wondrous complexity of the human hand. Twenty-seven bones working in concert with muscles, tendons, and ligaments extending up the forearm to produce a range of motions that gave us everything from stone tools to symphonies. Our hands are what we use to interface with the physical world on a fine level, and it’s understandable that we’d want mechanical versions of ourselves to include hands that were similarly dexterous.

That’s a tall order to fill, but this biomimetic mechatronic hand is a pretty impressive step in that direction. It’s [Will Cogley]’s third-year university design project, which he summarizes in the first video below. There are two parts to this project; the mechanical hand itself and the motion-capture glove to control it, both of which we find equally fascinating. The control glove is covered with 3D-printed sensors for each joint in the hand. He uses SMD potentiometers to measure joint angles, with some difficulty due to breakage of the solder joints; perhaps he could solve that with finer wires and better strain relief.

The hand that the glove controls is a marvel of design, like something on the end of a Hollywood android’s arm. Each finger joint is operated by a servo in the forearm pulling on cables; the joints are returned to the neutral position by springs. The hand is capable of multiple grip styles and responds fairly well to the control glove inputs, although there is some jitter in the sensors for some joints.

The second video below gives a much more detailed overview of the project and shows how [Will]’s design has evolved and where it’s going. Anthropomorphic hands are far from rare projects hereabouts, but we’d say this one has a lot going for it.

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Openhand Combines 3D Printing With Urethane Casting

February 25, 2015 by George Graves 8 Comments

Yale University brings us quite a treat with their Openhand Project.

If you’ve ever operated a robotic arm, you know that one of the most cumbersome parts is always the end effector. It will quickly make you realize what an amazing work of engineering the human hand really is, and what a poor intimation a simple open-close gripper ends up being.

[Yale] is working to bring tendon-driven robotic hands to the masses with an interesting technique of combining 3D printing and resin/urethane casting. Known as Hybrid Deposition Manufacturing (HDM), it allows the team to 3D print robotic fingers that also contain the mold for finger pads and joints, all built right into the 3D part. The tendon-driven fingers allow for a very simple design that are not only easy to make, but have a low parts count as well. Because of the human-like tendons, the fingers naturally curl around the object, distributing it’s force much more evenly and naturally, much like a human hand would. In the videos after the break, you can see the building process, as well as the hand in action.

Best news is that it’s all open source. They also include some python libraries so you can customize the CAD files fit your needs.

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