I used to work next to a group working on feedback for prosthetic limbs. It’s a pretty hard problem and they went through multiple methods (twisting skin, pulling skin, electrical stimulation, etc).

They actually just released their product and honestly I’m impressed. It can handle weight lifting to egg pinching and you can feel it:

http://www.psyonic.co/ability-hand

It uses vibration. Your brain adjusts very quickly, understanding what the sensory feedback implies after a few minutes really.

Sensory substitution [0] is amazing. There is (was?) a research group which created a belt that encoded the direction of north (or towards other points) in vibrations that always pointed towards north (the target) when the user turned. After a while, the users no longer perceived the vibrations but acquired a sense of north as entity itself. It is said to be very helpful to the blind as our sense of balance seems to be too imprecise for dead-reckoning [1], so things like walking unguidedly over a fields instead of following a track seems to be problematic. (I know no blind people myself, so I can not say if this is true in general). They founded a spin-off company that tries to commercialize the technology [2].

[0] https://en.wikipedia.org/wiki/Sensory_substitution [1] https://en.wikipedia.org/wiki/Dead_reckoning [2] https://www.feelspace.de/

I don't remember how well it worked and how far they went with the idea, but there was a team twenty-some years ago doing touch sensory research using a matrix of pins/dots that reacted to camera input, and attached to the back of blind people to make them "see".

Other research along these lines are "plotting" visual signals onto tongues. Here's an interesting article from 2009 talking about it:

https://www.scientificamerican.com/article/device-lets-blind...

"From the CPU, the signals are sent to the tongue via a "lollipop," an electrode array about nine square centimeters that sits directly on the tongue. Each electrode corresponds to a set of pixels. White pixels yield a strong electrical pulse, whereas black pixels translate into no signal. Densely packed nerves at the tongue surface receive the incoming electrical signals, which feel a little like Pop Rocks or champagne bubbles to the user."

It's been available in Europe since 2013, and the US FDA apparently approved the device in 2015:

https://www.medicaldaily.com/fda-approve-brainport-device-wh...

You're not referring to the North Paw are you?

Not sure if this is what GP is thinking of, but I think you're thinking of North Sense: https://www.vice.com/en_us/article/wnpvb5/cyborg-implant-nor...

Sorry for slow reply, but I did mean North Paw: https://sensebridge.net/projects/northpaw/

Anyone know if this also would translate to pain—say if the hand was crushed in an accident?

I have a problem with the title of the article: I don't think this is "beyond the functional". Being able to get some form of touch feedback when handling things is very much a functional aspect and a pretty important one at that.

I agree, "beyond the functional" to me implies something else like aesthetics or design.

I also met this title with revulsion. I submit that "beyond the mechanical" is more precise.

Non-subscriber friendly link: https://archive.is/zICt8