A four-fingered partial hand prosthesis in fuschia with black fingerpads is attached to a man's left hand (palm and thumb are original). He holds the left hand + prosthetic with his right hand and an aluminum hand prosthetic sits on the table to the left of his hands.

Designing A Simpler Prosthetic Finger

January 22, 2023 by Navarre Bartz 5 Comments

Prosthetic limb design is an area where desktop manufacturing has made huge strides, but there’s always room for improvement. For example, take a look at [Ian Davis] and his attempts to design a simpler prosthetic finger.

[Davis] favors his aluminum partial hand prosthetic for its strength, but because it was scratch built for his particular situation, it isn’t easy to recreate for someone else. To this end, he has started working on a simpler design that might be applicable in the future for people who want to build their own prosthetics. With less than ten major components per finger including the replaceable TPU fingerpads, this is a major step toward that end.

According to [Davis], one of the more exciting parts of the build is that while this hand has a more limited feature set, he was able to get it closer to the size of his natural hand. Because of the durability problems he’s experienced for day-to-day use of plastic prosthetics, he is having the next iteration 3D printed in stainless steel for further testing.

If you want to see some more interesting prosthetic designs, checkout the Kid Who Designed His Own Prosthetic Arm or this Skull Lamp Prosthetic Eye.

Meticulous Bionic Hand

November 12, 2020 by Matthew Carlson 12 Comments

[Will Cogley] is slowly but surely crafting a beautiful bionic hand. (Video, embedded below.) The sheer amount of engineering and thought that went into the design is incredible. Those who take their hands for granted often don’t consider the different ways that their digits can move. There is lateral movement, rotation, flexion, and extension. Generally, [Will] tries to design mechanisms with parts that can be 3D printed or sourced easily. This constrains the hand to things like servos, cable actuation, or direct drive.

However, the thumb has a particularly tricky range of motion. So for the thumb [Will] designed to use a worm geared approach to produce the flexing and extension motion of the thumb. These gears need to be machined in order to stand up to the load. A small side 3d printed gear that connects to the main worm gear is connected to a potentiometer to form the feedback loop. Since it isn’t bearing any load, it can be 3d printed. While there are hundreds of little tiny problems still left to fix, the big problems left are wire management, finalizing the IP (Interphalangeal) joints, and attaching the whole assembly to the forearm.

All the step files, significants amounts of research, and definitions are all on [Will’s] GitHub. If you’re looking into creating any sort of hand prosthetic, the research and attention [Will] has put into this is work incorporating into your project. We’ve seen bionic hands before as well as aluminum finger replacements, but this is a whole hand with fantastic range and fidelity.

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What If You Could Design Your Own Aluminum Hand?

October 22, 2020 by Matthew Carlson 21 Comments

[Ian Davis] has decided to start over on his hand. [Ian] is missing four fingers on his left hand and has for a year now been showcasing DIY prosthetics on his YouTube channel. Back in July, we covered [Ian]’s aluminum hand.

Why aluminum? [Ian] found himself reprinting previous versions’ 3D printed plastic parts multiple times due to damage in the hinged joints, or UV damage rendering them brittle. With an ingenious splaying mechanism and some sensors powered by an Arduino, [Ian] has been wearing the custom machined aluminum hand on a daily basis.

However, as with many makers, he had that itch to revisit and refine the project. Even though the last version was a big jump in quality of life, he still found room for improvement. One particular problem was that the sensors tended to shift around and made it hard to get an accurate reading. To overcome this, [Ian] turned to a molding process. However, adding a stabilizing silicon layer meant that the design of the prosthetic needed to change. With several improvements in mind, [Ian] started the process of creating the plaster positive of his palm, working to create a silicon negative. The next step from here was to create a fiberglass shell that can go over the silicone with sensor wires embedded into the fiberglass shell.

It has been amazing to see the explosion in 3D printed prosthetics over the past few years and hope the trend continues. We look forward to seeing the next steps in [Ian’s] journey towards their ideal prosthetic!

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3D Printed Prosthesis Reads Your Mind, Sees With Its Hand

July 17, 2019 by Erin Pinheiro 4 Comments

Hobbyist electronics and robotics are getting cheaper and easier to build as time moves on, and one advantage of that is the possibility of affordable prosthetics. A great example is this transhumeral prosthesis from [Duy], his entry for this year’s Hackaday Prize.

With ten degrees of freedom, including individual fingers, two axes for the thumb and enough wrist movement for the hand to wave with, this is already a pretty impressive robotics build in and of itself. The features don’t stop there however. The entire prosthesis is modular and can be used in different configurations, and it’s all 3D printed for ease of customization and manufacturing. Along with the myoelectric sensor which is how these prostheses are usually controlled, [Duy] also designed the hand to be controlled with computer vision and brain-controlled interfaces.

The palm of the hand has a camera embedded in it, and by passing that feed through CV software the hand can recognize and track objects the user moves it close to. This makes it easier to grab onto them, since the different gripping patterns required for each object can be programmed into the Raspberry Pi controlling the actuators. Because the alpha-wave BCI may not offer enough discernment for a full range of movement of each finger, this is where computer aid can help the prosthesis feel more natural to the user.

We’ve seen a fair amount of creative custom prostheses here, like this one which uses AI to allow the user to play music with it, and this one which gives its user a tattoo machine for an appendage.

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Water Level Sensors, Alexa In A Fish, And Modular Synths During World Create Day

March 19, 2018 by Mike Szczys 3 Comments

On Saturday we saw a flood of interesting hacks come to life as more than 100 community organized meetups were held for World Create Day. Thank you to all of the organizers who made these events possible, and for everyone who decided to get together and hack.

Students Learning Hardware Design in Islamabad, Pakistan

The students at LearnOBots took on a slew of great projects during World Create Day like a smart medicine dispenser, electronics that control mains appliances, parking sensors, and a waste bin that encourages you to feed it. The group did a wonderful job of showing off their event by publishing several updates with pictures, stories, and video presentations from all the students. Nice work!

Daniyal LED Matrix

Haya and Taha water level sensor

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Nerds Unite: Prosthetics Inspired By Comics And Beyond!

March 6, 2018 by Lara Grant 39 Comments

Open Bionics is a company creating prosthetics inspired by heroines, heroes and the fictional worlds they live in. The designs emblazoned on their first set of bionic hands include ones drawn from Queen Elsa from Disney’s Frozen, and Marvel’s Iron Man. The best thing about what they are doing is they offer you, dear reader, a chance to lend your own super powers of design and engineering. Open Bionics offers up 3D print files for several hand designs, hardware schematics and design files for their controller boards, firmware, and software to control the robotic hands with. Other than their website, you can also find all of the files and more on their GitHub account. If you’d like to devote a good amount of time and become a developer, they have a form to contact them through. To help with sourcing parts for your own build, they sell cables for tendons, muscle sensors, and fingertip grips in their online store.

We first came to learn about this company through a tipster [Dj Biohazard] who pointed to a post about their partnership with an 11-year-old Tilly, who is pictured on the left. Her bionic hand is an Open Bionics prototype whose design is based on the video game, Deus Ex. The best way products like these are improved are through the open source community and people like her.

Specific improvements Open Bionics state on their website are:

The customised bionic arms are manufactured in under 24 hours and the revolutionary socket adjusts as the child grows.
The bionic arms are light and small enough for those as young as eight.
The bionic arms use myoelectric skin sensors to detect the user’s muscle movements, which can be used to control the hand and open and close the fingers.

Read more about Tilly’s story and her partnership with Open Bionic’s on Womanthology. Tilly seems to have a dream of her own to “make prosthetics a high fashion piece – something that amputees can be proud to wear.”

We at Hackaday have written about several open source prosthetic developments such as a five-day event S.T.E.A.M. Fabrikarium program taking place at Maker’s Asylum in Mumbai and the work of [Nicholas Huchet]. What superhuman inspired designs would you create?

Move A Robotic Hand With Your Nerve Impulses

December 31, 2016 by Jenny List 7 Comments

Many of us will have seen robotics or prosthetics operated by the electrical impulses detected from a person’s nerves, or their brain. In one form or another they are a staple of both mass-market technology news coverage and science fiction.

The point the TV journalists and the sci-fi authors fail to address though is this: how does it work? On a simple level they might say that the signal from an individual nerve is picked up just as though it were a wire in a loom, and sent to the prosthetic. But that’s a for-the-children explanation which is rather evidently not possible with a few electrodes on the skin. How do they really do it?

A project from [Bruce Land]’s Cornell University students [Michael Haidar], [Jason Hwang], and [Srikrishnaa Vadivel] seeks to answer that question. They’ve built an interface that allows them to control a robotic hand using signals gathered from electrodes placed on their forearms. And their write-up is a fascinating read, for within that project lie a multitude of challenges, of which the hand itself is only a minor one that they solved with an off-the-shelf kit.

The interface itself had to solve the problem of picking up the extremely weak nerve impulses while simultaneously avoiding interference from mains hum and fluorescent lights. They go into detail about their filter design, and their use of isolated power supplies to reduce this noise as much as possible.

Even with the perfect interface though they still have to train their software to identify different finger movements. Plotting the readings from their two electrodes as axes of a graph, they were able to map graph regions corresponding to individual muscles. Finally, the answer that displaces the for-the-children explanation.

There are several videos linked from their write-up, but the one we’re leaving you with below is a test performed in a low-noise environment. They found their lab had so much noise that they couldn’t reliably demonstrate all fingers moving, and we think it would be unfair to show you anything but their most successful demo. But it’s also worth remembering how hard it was to get there.

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