I would search up "Galvanic Vestibular Stimulation". It affects balance which could be used to imitate gravity (-ish).
Wow, this technology has come a long way from its late 1700s origins, when Luigi Galvani invented the battery and spent 20 years running currents through various body parts of living and dead nonhuman and human animals! This 2005 NBCNews article
describes work by Taro Maeda, then at NTT Communication, where they were able to effectively steer people around by causing a false “leaning” sensation using GVS. Madea’s been an IT professor at Osaka U since 2007, so I’m not sure what’s become of the NTT work, but he seems to still be involved in GVS, having published a paper with it in the title in 2012.
As the NBCNews article mentions, there’s no confident theory of how GVS works, which clearly hinders its development. The 2011 paper "What Does Galvanic Vestibular Stimulation Actually Activate?"
by Bernard Cohen, Sergei Yakushin and Gay Holstein leans toward an explanation suggesting it’s application is limited, because it effects only vestibular system
nerves that produce leaning (the otholithic organs
), not rotating (the ampullary cupulae
), sensations, but even if limited, it seems to me it could nicely enhance VR experiences. According to the NBCNews article, people were enjoying it (some people – other found it dizzying and unpleasant) in demonstration race car and music/dancing games back in 2005.
I’ve long wondered it a system that stimulated the vestibular system not by directly electrifying its nerves, but by moving the its fluid, could provide an immersive simulation of linear and angular acceleration. Perhaps a magnetic field could be used to precisely “stir” it, much like magnetic lab stirrer works. A ferromagnetic fluid could be injected into inner ear, or perhaps a strong enough field could move the water in the fluid sufficiently without this.
I think It’s important to understand, though, that the sensation of gravity – of “which way is down” – isn’t entirely, or even mostly, due to the vestibular system. We also sense it through the force exerted by our legs, limbs, and other body parts. So a VR system that doesn’t directly interface with the brain to replace normal nerve input would need not only to fiddle with the vestibular system, but with the body’s many proprioceptor
nerves, either by stimulating them artificially, or by pushing and pulling on body parts. I imagined the latter kind of system in this post
, this one
and this one
, which I call a “deep dive waldo” system.
I think some audio company has developed(or is developing) a headset that has that tech built in, it's marketed directly to VR as I recall.
I think you’re referring to an experimental gadget from Samsung called the Entrim 4D
. I don’t think you can buy one yet (hence the “experimental” part), but the article I linked to said they were being publicly demoed in a month ago in the South by Southwest vestival in Austin TX.