I like the idea of voluntary prosthetics. But IME, your brain needs time to get used to these kinds of things and build them into its proprioception.

For example, if you wear a vest containing haptic motors which constantly buzz towards North, your brain will start to build an understanding of directionality into your worldview, like how some migratory birds navigate. And when you take the vest off after wearing it for awhile, you'll feel oddly disoriented for some time. Try it out: motors and microcontrollers are cheap.

This project looks sleek, but that strap between the thumb and index finger looks tight in the screenshot. Is it comfortable enough to wear for 18 hours a day?

And if the thumb is controlled from your feet, what happens when the battery dies or the radio is disrupted? Brains do not like unresponsive limbs.

Great concept, though - can't wait to see how it develops.

>But IME, your brain needs time to get used to these kinds of things and build them into its proprioception.

Their video [1] says that it's very intuitive and people can do basic stuff with it in minutes.

[1] https://vimeo.com/551468278

Huh. I've chatted to Dani several times (we go to the same bar and share a circle of friends). She is hella smart. Sadly she's yet to have had the third thumb with her whenever we've met, but I know a bunch of our mutual friends who've tried it and seemed to get on with it very quickly indeed. Did not expect to find it on the front page of hacker news though!

Hey there! Would you mind talking to her on my behalf?

I am actually missing a thumb entirely on my right hand and had at one point reached out to both her and the researchers she worked with on it. She never responded and the researchers said she held the rights to it so I would have to talk to her.

I would be EXTREMELY interested in speaking with her about either testing or even purchasing one if I find it is something that could help me!

I have an email in my profile she can reach me by.

Have you checked out Ian Davis? He has been building[1] mechanical prosthetic hand-fingers(4) for a while now, He's currently in the process of upgrading his old design.

He's a gentleman and I think he's responsive to communication regarding replicating his designs.

[1]https://www.youtube.com/channel/UCv1xxFkEiAdCVy6foEEUIvw

Fantastic, thanks for the link! I will take a look into him as well.

Hand tracking in VR is mature enough for such research. You can transplant a finger from one hand onto another by copying over the skeleton poses. Physical colliders synchronized to skeleton position allow you to interact with objects of different shapes. There is no haptic feedback, which is also true for this artificial thumb.

As for real life: while it would be amazing to have a second thumb semi-permanently, I would prefer it to be pure mechanical contraption without any running software.

Mechanical contraption is exactly how I would describe Ian Davis's projects. You should check out his mechanical hand if you haven't already: https://www.youtube.com/watch?v=V9i8qqYHvqA

From the site:

> The Third Thumb is a 3D printed thumb extension for your hand, controlled by your feet. The project investigates the relationship between the body and prosthetic technology in new ways.

Looks like you control it with your big toe via a pressure sensor inside a shoe? Sounds cool!

I am surprised they didn't use electromyography bands which are a perfect fit for this particular application (like those by Ctrl Labs and Thalmic labs). Perhaps their budget didn't allow for making custom amplifier chips.

She mentions this in her Tedx talk [0]. She wanted something more orthogonal to the existing hand muscles.

The easier and cheaper method is probably better for her scope as well.

https://www.youtube.com/watch?v=UD_LwZD2Kls

I believe she made a mistake here: neural signal latency to toes would be nearly double that of latency to fingers.

I disagree: I find that she makes an excellent point about the choice she made in the video linked above. She is a designer, exploring ideas about body augmentation. She is not (and nor is anyone else) at the stage of perfecting a design so that it become the most performant. "Premature optimization..." and all that.

From your comment is sounds like you actually agree :)

Would love to try it. How can I get one?

Reminds me of https://news.mit.edu/2014/getting-grip-robotic-grasp-0718

it's not often i find myself wishing for content to be presented in video form - usually the exact opposite. but in this case, i really want to see a video of this in operation.

Video is here, and a link to the paper: https://twitter.com/SciRobotics/status/1395413569571786752

The first image in the website links to a video[1] showing what it can do and why they're researching it.

[1] https://vimeo.com/551468278

Thanks. I clicked a bunch, but I guess not on that one

Dani did a TED talk about it https://youtu.be/UD_LwZD2Kls

It would be great for my piano playing. Ascending and descending scales would easily sound exactly the same.

I want one, anywhere to get the designs?

Looks great for bar staff

I wonder if this would improve or hinder my Jiu Jitsu.

Don't squeeze your thumb when you punch becomes doubly true.

cool but creepy