EEG Cat Ears (2018)

>>our ears already can move a slight bit by its own muscles.

Not everyone can do that though. My wife can easily twitch her ears by just thinking about it, I cannot no matter how hard I try - it's just like there is no nerve link to whatever is there.

It would be a better control mechanism. NeuroSky (the headset used here) is only good as an eye blink detector and even at that it’s not great. EEG reading on the forehead, without gel is always really bad because there are no obviously interpretable signals (frontal cortex is way more complex than, say motor regions or the occipital nerve), the skin is tougher due to no hair, and is way too much muscle interference.

Something with two electrodes behind ears (or wherever the muscles responsible for moving ears are) could be even used as a tool to train to move your (human) ears.

I saw something where someone tried to do that - https://hackaday.com/2020/01/02/assistive-technolgy-switch-i...

It seems to use a type of camera to measure movement in the ear.

I was thinking perhaps add a pair of microphones to the headset and have the ears react to loud sounds — attempt to angle towards the source of the loud sound.

Mux that in with the neural input.

I sat behind a girl at school whose ears would involuntarily move. Like quite a _lot_! Like a dog. It freaked everyone right out.

honestly, looking at the devices and not seeing the EEG traces, I half suspect that a lot of the input is already muscle artifact. Even w/ dedicated medical EEG w/ the fancy electrodes and conducting goop, it's plagued w/ a ton of eyelid/scalp muscle artifact.

Or even if you don't use the muscles, is there a way to build something that isn't a noisy servo.

EEG and MRI are based on two completely different physical measurements. They have nothing whatsoever to do with each otyer, in terms of why they work. Medical EEG machines are very small, and their size relative to MRI machines does not factor into how effective the EEG is.

I mean, would you doubt that a stethescope can work, because it's so much smaller than an MRI? No, that would be ridculous. Same with your comparison vs EEGs.

Just read the WP articles on MRIs and EEGs. You'll understand it.

EEG studies are rife with issues, but there are a number of very well replicated results. Obviously they do nothing to localize an effect, but there are absolutely clear correspondences between the readings of an EEG and at least some cognitive activity.

Will you get that nice FMRI resolution? Absolutely not. But the effects you do get are fascinating, and super weird.

Now that's the EEG I've seen in labs. Not sure if there is a similarly good commercial offering.

the underlying concept of EEG hasn't changed since the initial ones in 1929. Basically just electrodes trying to detect whatever LFP (aggregate electrical potentials) comes across the cranium. The clinical ones are considered a rough gauge of brain activity, good enough to reliably detect large seizures or a generalized slowing in patients who are delirious but that is about it.

There's MEG which tries to do the same thing but using magnetic detectors instead of scalp electrodes, but those systems are large and unwieldy

In surgery, they do intracranial subdural electrodes which give you better cortical LFP because the electrodes are almost directly on top of the brain and not having to measure through bone.

Then there are the single unit electrodes or things like the Black Rock systems Utah array where thin probes penetrate the brain into deeper structures but obviously have much more special circumstances where they are able to be used.

We're building an eeg device for sleep, and work with a colleague who is on the Emotiv team, so I've got a bit of experience.

The state of BCI is improving, but one of the challenges is for many of the things we'd want to do, you need electrodes placed in areas that have hair. There are flexible sensors that can find their way through hair, but as somebody with thick curly hair, they are not fit for everyone yet. Then there is movement that also needs to be considered for many of these devices.

This is why something like Muse headband used for meditation is a good starting point. You are placing the electrodes on areas that don't have hair, and the use case is while being still, so you have consistent contact without movement.

At my start-up (https://soundmind.co) we're using forehead mounted electrodes which measure your brain waves during sleep, and we use sound to improve sleep performance. So like Muse (which you can also use during sleep, but does not yet provide stim), we benefit from measuring very small signals when you are mostly still.

I think if we were walking down the street with our headband trying to control cat ears, you'd get lots of EEG artifacts due to movement of the electrodes.

My 2 cents.

Yes, it's a Necomimi clone. The big year for those was 2012. They detect three mental states - idle/relaxed, attentive, and surprised. I saw a group of cosplay girls wearing them at a convention. Someone called out the name of one of the girls. Her ears, and not the ears of the others, popped up. A review reported someone playing a video game had their ears in the "attentive" position while playing a level, and the ears would droop between levels.

Good idea, but too bulky. It needed cosplay big hair to hide the machinery. The big head-mounted box is mostly the 4 AAA batteries. If someone revives this, the mechanism needs to be about half the size and better fitted to a head.

The Nekomimi people also came out with a powered cat tail, but that was a total flop.

I was really impressed with the sketches. I always thought those were more of an engineering "suggested best practice" but this is a good reminder that a visual sketch can act as a reference while also showing how pieces might fit together.

It’s a Makerbot cupcake, which is pretty old by this point (~10 years). One of the first “affordable“ 3D printers.

https://makerbot.fandom.com/wiki/Cupcake

Those exact ears were reference material for this project.

> I began by looking at the youtube concept video for the necomimi brainwave-controlled ears. My intent wasn't to copy their implementation, but I was curious what kind of motion they had decided on.

Neat. I bought a pair at PAX many years ago. Sadly they stopped working after a week or so.

The ones that you linked are called Necomimi, I bought them and they still work. The one thing that they should really improve is the quality of the motors because they are extremely loud which kind of defeats the point of having a mode which shows you your meditation state and relaxed state. I wish someone would make an update and improved version. Another thing that bothered me is that it needs FOUR AAA batteries, which is good from the environment point of view. But very bulky and kinda annoying from the UX point of view.

The same company also made a tail, but I didn't have a chance to test it nor did I buy it.

Yeah, because the guy is animating in every image for some reason