Imagine being able to understand your own brain state simply by putting on a pair of earbuds. You would be able to tell when you are focused, stressed, tired, or ready to sleep, all without wearing a bulky headset. With recent progress in wearable electronics and brain-monitoring sensors, this idea is becoming more realistic. In this report, I introduce NeuroBud, a practical and scientifically grounded in-ear brain-monitoring device that looks and feels like ordinary wireless earbuds. The goal is to make brain-state tracking comfortable enough for daily use while still providing meaningful data. NeuroBud uses in-ear EEG and optical sensing, both of which are backed by peer-reviewed research. Throughout this report, I explain the technology, design choices, user experience, validation process, and real-world considerations that make the device feasible.
The Wearable Brain Monitor: Engineering a Consumer-Ready Device
Introduction
Core Technology and Measurements
To balance scientific accuracy with everyday comfort, NeuroBud uses a combination of in-ear EEG electrodes and optical sensors. The EEG electrodes are positioned along the inner walls of the ear canal, where they pick up brain activity. Several studies have shown that the ear can be a reliable site for EEG measurements. For instance, Mikkelsen, Kappel, Mandic, and Kidmose (2015) characterized ear-EEG and demonstrated that alpha rhythms and event-related potentials can be recorded from the ear canal. Subsequent work has confirmed that ear EEG is feasible for a range of signals and settings, including attention and sleep-related activity (Jeong & Jeong, 2020; Mikkelsen et al., 2017).
In addition to EEG, NeuroBud includes optical sensors that operate using reflected light to measure blood volume pulse, heart rate variability, and slow changes in blood oxygenation. The ear is a good location for photoplethysmography because it has stable blood flow and is less affected by movement compared to the wrist. Research by Lee, Lee, and Kim (2019) confirmed that ear-based PPG can produce high-quality heart-rate signals. Similarly, Goverdovsky, Looney, Kidmose, and Mandic (2015) demonstrated that combining ear-based optical sensing with EEG yields meaningful physiological monitoring over long periods.
From these signals, NeuroBud estimates several useful metrics. Attention level can be inferred from changes in alpha and theta waves, which have well-established links to cognitive engagement (Klimesch, 2012). Stress and relaxation can be estimated using a mix of HRV and patterns in frontal EEG asymmetry, which relate to emotional state (Thibodeau, Jorgensen, & Kim, 2006). Cognitive load is estimated from increases in theta activity and decreases in parietal alpha (Gevins & Smith, 2003). During sleep, ear-EEG features can be used to perform sleep staging (Mikkelsen et al., 2017). Because these metrics are supported by research, the feedback provided by NeuroBud has scientific legitimacy rather than being speculative.
Hardware Design and Form Factor
NeuroBud is designed to resemble premium wireless earbuds, which makes it comfortable, discreet, and socially acceptable to wear. Each earbud weighs around 5 to 6 grams and has silicone tips that help maintain soft, stable contact with the ear canal. The dry EEG electrodes are embedded in the silicone material, while the optical components are built into a small transparent window. This design allows the earbuds to stay secure without irritating the skin or requiring gels or adhesives.
From a technical standpoint, the earbuds include a small processor for basic filtering and noise reduction, while more demanding computations take place on the userโs smartphone to conserve battery life. The battery lasts approximately 10 to 12 hours per charge, and the charging case extends the total usage time to about 30 hours. Bluetooth Low Energy is used for wireless communication. Because the device is intended for daily wear, it needs to withstand motion and environmental conditions. NeuroBud would be rated at least IPX4 for sweat and moisture resistance. The firmware uses adaptive filters to reduce noise from jaw movement, walking, and other natural motions. It also monitors electrode contact quality and alerts the user if the signal becomes unreliable. There are trade-offs: ear-EEG provides fewer channels than a full EEG cap, and the optical sensors only measure shallow physiology. However, these limitations are acceptable because the device focuses on general brain-state tracking, not clinical diagnosis.
User Experience and Software
A well-designed smartphone app is essential for making the device intuitive. The app presents a clean dashboard that shows daily patterns in focus, stress, and sleep quality. Real-time feedback is available during active sessions, such as study periods or meditation. Instead of raw EEG waves, the app displays easy-to-understand gauges, trends, and color-coded indicators.
The app also includes different modes. For example, Focus Mode gives live feedback that helps users stay on task. Calm Mode provides gentle guidance for reducing stress, based on HRV and EEG changes. Sleep Mode tracks sleep stages and provides a summary in the morning.
NeuroBud includes an AI-based coaching system that learns from the userโs habits over time. It might highlight periods when focus is naturally highest or suggest breaks during times of elevated stress. The goal is not to prescribe behavior but to support healthy, informed routines. Students, professionals, people with demanding schedules, and individuals who want to improve their sleep could all benefit from these insights. NeuroBud aims to make mental and cognitive wellness easier to understand and maintain, similar to how step counters made physical activity more accessible.
Validation and Scientific Credibility
To avoid falling into the trap of โneuro-wellness hype,โ NeuroBud requires a thorough validation process. The first stage would compare its ear-EEG data with standard scalp EEG in a controlled lab setting. Previous studies already suggest high correlations between ear and scalp signals, but direct testing is necessary to confirm similar accuracy in the finished product.
Next, several behavioral studies would test whether the deviceโs metrics actually relate to real-world performance. For example, the attention score could be compared to performance on sustained-attention tasks. The stress index could be compared to cortisol samples or validated stress inventories. Sleep staging should be tested against full polysomnography, which is considered the gold standard for sleep measurement.
A long-term reliability study would also be necessary to ensure the device gives consistent readings across weeks and months. Transparency is important as well. NeuroBud would publish its signal-processing methods and provide confidence levels to users so they understand when readings are strong or when data quality is low.
If marketed strictly as a wellness device, NeuroBud would not need to follow strict medical-device regulations. However, if clinical claims are intended, the company would follow the appropriate regulatory frameworks, including guidelines for Software as a Medical Device.
Business and Market Considerations
For the device to succeed, it has to be affordable, appealing, and ethically responsible. Based on the cost of components, the manufacturing cost would likely fall around 50 to 55 CA dollars per unit. This supports a retail price between 149 and 199 US dollars, which places it in the same range as high-end earbuds and smartwatches.
The main target market includes university students, young professionals, productivity-focused users, meditation enthusiasts, and people interested in sleep tracking. Existing products such as the Muse headband and Neurosity devices can be effective but are often bulky or too noticeable for everyday use. NeuroBud stands out because it fits into a form factor that people already use.
Ethical issues must be taken seriously. Continuous physiological monitoring can raise concerns about privacy, especially if employers or advertisers attempt to access this kind of data. NeuroBud would include strong encryption, avoid storing raw brain signals on company servers, and strictly prohibit selling user data. Users would receive clear explanations of what the device measures, what it cannot detect, and how their data is protected.
Conclusion
NeuroBud offers a realistic and scientifically grounded vision for everyday brain-state monitoring. By combining ear-EEG and optical sensing inside a pair of comfortable earbuds, it provides insights about attention, stress, cognitive load, and sleep without requiring special equipment or complicated setup. Although it does not replace clinical EEG systems, it fills a growing demand for accessible mental-wellness technology. With thoughtful engineering, careful validation, and ethical safeguards, NeuroBud has the potential to make cognitive and emotional self-awareness a normal part of daily life.
References
- Gevins, A., & Smith, M. E. (2003). Neurophysiological measures of working memory and individual differences in cognitive ability. Behavioral Neuroscience, 117(6), 1062โ1070.
- Goverdovsky, V., Looney, D., Kidmose, P., & Mandic, D. P. (2015). In-ear EEG from viscoelastic generic earpieces: Robust and unobtrusive 24/7 monitoring. IEEE Sensors Journal, 17(3), 569โ576. https://doi.org/10.1109/JSEN.2015.2471183
- Klimesch, W. (2012). Alpha-band oscillations, attention, and controlled access to stored information. Trends in Cognitive Sciences, 16(12), 606โ617. https://doi.org/10.1016/j.tics.2012.10.007
- Lee, Y., Lee, S., & Kim, J. (2019). Earable PPG: Estimating heart rate from ear-worn hearables. Sensors, 19(19), 4215. https://doi.org/10.3390/s19194215
- Mikkelsen, K. B., Kappel, S. L., Mandic, D. P., & Kidmose, P. (2015). EEG recorded from the ear: Characterizing the ear-EEG method. Frontiers in Neuroscience, 9, 438. https://doi.org/10.3389/fnins.2015.00438
- Mikkelsen, K. B., Villadsen, D. B., Otto, M., & Kidmose, P. (2017). Automatic sleep staging using ear-EEG. Biomedical Engineering Online, 16, 69. https://doi.org/10.1186/s12938-017-0356-5
- Jeong, D.-H., & Jeong, J. (2020). In-ear EEG based attention state classification using echo state network. Brain Sciences, 10(6), 321. https://doi.org/10.3390/brainsci10060321
- Thibodeau, R., Jorgensen, R. S., & Kim, S. (2006). Depression, anxiety, and resting frontal EEG asymmetry. Journal of Abnormal Psychology, 115(4), 715โ729. https://doi.org/10.1037/0021-843X.115.4.715
- Athavipach, C., Pan-ngum, S., & Israsena, P. (2019). A wearable in-ear EEG device for emotion monitoring. Sensors, 19(18), 4014. https://doi.org/10.3390/s19184014
Other Course Work
๐ Assignment 1: EEG Analysis
๐ assignment1_eeg_filtering_GraceShin - Grace Shin.ipynb
Jupyter Notebook๐ก Opens in Google Colab for interactive execution. Requires Google account.
๐จ Assignment 2: BrainImation
๐ Assignment2_PSYCH403 - Grace Shin.pdf
View Original PDFBrainwave Visualization Using Ocean Waves and the Sky
By: Grace Shin
For this project, I decided to use real-time brain wave data to create a visualization. I wanted to create an
artistic expression that shows different states of the mind, whether that would be calm or alert. To do this,
I designed a visualization that shows the waves of an ocean, as well as a gradient sky that both respond in
real time to EEG signals from either the simulation data or real-time data.
The concept of the ocean visualization is to depict sea waves that exist under a shifting sky. I took
inspiration from the alpha waves visualization, where brain wave activity such as alpha and beta
frequencies affect how the waves move. When a user is more relaxed with higher alpha waves, the ocean
waves are coded to become smoother and slower, while the sky and ocean colours turn warm and bright.
When the user is alert or focused with higher beta waves, the ocean becomes choppier to represent the
mental state, while the sky turns cooler. This essentially depicts the state of the mind using a visualization
of nature.
For the technical implementation, I used the BrainImation platform with P5.js to build the visualization.
By using the simulation data provided by the website, I was able to test my code as if it was using brain
waves in real-time, and see how the scenery changed with the changes in alpha and beta frequencies. By
using values such as eegData.alpha, eegData,beta, eegData.theta, and eegData.meditation, I was able to
create different visualizations based on the parameters. For example, the alpha waves control the
smoothness, beta controls turbulence, theta shifts the colour, and meditation changes the brightness. The
ocean uses layered sine waves to create the wave-like motion, and the colours used are supposed to create
a calming, aesthetic scenery.
A challenge I had was finding a form of visualization of the waves that would ensure a smooth animation
while being aesthetically pleasing. At first I felt that the waves by themselves looked too simple, and
decided to incorporate the gradient colour changing sky in order to create a better imagery. As well, to
smooth out the fluctuations in wave frequencies, I used smooth mapping to create better transitions.
Though having no headset or real-time data was a bit challenging, I felt that the simulation data provided
by BrainImation was useful in letting me test and visualize how my code worked when values fluctuated.
Overall, I learned a lot from this project, such as how coding and neuroscience donโt always have to be
something non-creative or non-artistic. I saw how one could incorporate artistic expression into
neuroscience and technology through this assignment. By creating code that visualizes the mental state of
a user using real-time brainwaves from EEG data, I was able to merge the two worlds of art and science
together in a way where it was more tangible to understand concepts that seemed a bit more intimidating
before. By mirroring the userโs mind in a natural setting through the calm and aesthetic visualization of
ocean waves and a gradient sunrise sky, I was able to achieve this.
Code pasted here as google forms would not let me upload the .js file:
// inspired by alpha wave visualization
// creates different wave speed and smoothness based on the user's brain
state
// by: Grace Shin
let t = 0 ;
function setup () {
colorMode (HSB , 360 , 100 , 100 , 1 ) ; // set to hsb to easily control
noStroke () ;
}
function draw () {
// sky (gradient) - changes from teal to pink depending on theta
activity, where low theta makes sky cooler (bluish) and high theta makes
it look warmer (pinkish) to represent meditative state
let skyHue = map (eegData . theta , 0 , 1 , 200 , 320 ) ; // teal to pink tones
let skyBright = map (eegData . meditation , 0 , 1 , 25 , 85 ) ; // brightness
also increases with meditation level
for ( let y = 0 ; y < height * 0.7 ; y ++ ) {
let inter = map (y , 0 , height * 0.7 , 0 , 1 ) ;
let hue = lerp (skyHue , skyHue + 40 , inter) ;
let bright = lerp (skyBright , 25 , inter) ;
stroke (hue , 40 , bright) ;
line ( 0 , y , width , y) ;
}
// ocean waves
fill (skyHue - 20 , 60 , 70 , 1 ) ; // base colour
beginShape () ;
for ( let x = 0 ; x <= width ; x += 10 ) {
let nx = x * 0.01 ;
let waveBase = height * 0.65 ;
// shape of the waves differ based on brain waves
let calmFactor = map (eegData . alpha , 0 , 1 , 1.2 , 0.5 ) ; // changes how
smooth or wavy the waves look, higher alpha = smoother waves
let turbulence = map (eegData . beta , 0 , 1 , 0.4 , 1.4 ) ; // adds random
motion based on beta activity (stress/alertness)
let y = waveBase +
sin (nx * 3 + t) * 40 * calmFactor * turbulence + // combine
sine waves to create natural wave pattern
sin (nx * 1.3 + t * 0.6 ) * 25 * calmFactor ;
vertex (x , y) ;
}
vertex (width , height) ;
vertex ( 0 , height) ;
endShape (CLOSE) ;
// speed gets slower with calmness
// waves slow down with calmness (higher alpha)
let calmness = (eegData . alpha + eegData . meditation ) / 2 ;
let baseSpeed = 0.02 ;
let calmSpeed = map (calmness , 0 , 1 , 1.2 , 0.3 ) ; // 1.2x when stressed to
0.3x when calm
t += baseSpeed * calmSpeed ;
// for simulation / realtime data
if ( ! eegData . connected ) {
fill ( 0 , 0 , 100 , 0.9 ) ;
textAlign (CENTER , CENTER) ;
textSize ( 20 ) ;
text ( " Connect your Muse headset or use 'Simulate Data' ", width / 2 ,
height / 2 - 10 ) ;
textSize ( 16 ) ;
fill ( 0 , 0 , 70 , 0.7 ) ;
text ( " and observe how the waves slow when you relax ", width / 2 ,
height / 2 + 20 ) ;
}
}
๐ฅ assignment2 - Grace Shin.mp4
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๐ฏ Midterm Project
๐ Shin_midterm_part1and2 - Grace Shin.pdf
View Original PDFPart 1
The novel BCI concept I implemented was target brain state training (neurofeedback). This
implementation was built based on my previous wave visualization, but introduces an adaptive
neurofeedback element that aids users in training their calmness in real time. Rather than simply showing
brain activity visually, this project uses a feedback loop where sustained calmness is represented by a
progress bar.
The program works by reading real-time EEG data and using alpha and meditation levels as indicators of
relaxation, while beta and theta levels affect color and motion. Since the user is able to see these values
translated into visual changes in the form of ocean waves, it is easier for them to track and regulate their
calmness level. As there is also the addition of a calmness bar to indicate their level of calmness, this
program creates a feedback loop where the user can learn to associate mental calmness with stable,
tranquil visuals and simultaneously track their levels numerically too.
What differentiates it from a basic parameter control system is that the user is able to self-regulate rather
than something direct. The user is not consciously controlling something, but rather using their
physiological state to drive the experience. As the visuals of the program respond to fluctuations in brain
activity in real-time, this allows the user to focus and practice self-regulation rather than control.
I learned, through implementing this project, how small EEG changes can be visually represented through
real-time feedback, and how smoothing and timing are important for the user experience to be coherent.
As well, I was able to gain insight into how neurofeedback interfaces can promote mindfulness and
self-regulation through allowing users to see their mental state change in real-time. Though it was harder
to see changes and test the program due to using simulation data, it was overall a very interesting learning
experience where I could create something that allowed humans to self-regulate through their own
mindful control.
Part 2
For this experiment, I chose to measure the P300 (P3) component, which is one of the most well-studied
event-related potentials in cognitive neuroscience. The P300 is a positive wave that appears around 300 to
600 milliseconds after a person detects something unexpected or important. Itโs linked to how the brain
allocates attention and updates working memory when something stands out from what it expects. The
component was first discovered by Sutton and colleagues in 1965, and itโs often studied using whatโs
called an โoddballโ paradigm, where rare or target stimuli are mixed in with frequent standard ones.
In my experiment, I used a simple visual oddball setup with two stimulus types: a blue circle representing
the frequent (standard) condition and a red circle representing the rare (target) condition. The rare
stimulus appears on about 20% of trials, while the frequent one appears 80% of the time. Each trial starts
with a short baseline period, followed by a brief stimulus display and then a rest phase. The idea is that
the rare stimuli are unexpected and grab more attention, which should produce a larger P300 response
compared to the frequent ones. The timing is controlled so that each trial lasts 1.5 seconds, with an epoch
window of -200 to +800 milliseconds around the stimulus.
The system collects EEG epochs separately for each stimulus type and averages them over multiple trials.
Averaging reduces random noise and highlights the consistent response patterns related to the stimuli. The
code displays both averaged ERP traces on the same graph, with the rare and frequent conditions in
different colors, so itโs easy to compare them. The display also includes labeled time markers, a zero line
at stimulus onset, and counters showing how many trials have been collected for each category. Over
time, as more trials are added, the ERP plots become smoother and more distinct.
If this were tested with real EEG data, I would expect to see a clear positive bump (the P300) between
about 300 and 600 milliseconds after the rare stimulus, while the frequent stimulus would show a smaller
or flatter response in that same window. This difference reflects the brainโs stronger orienting response
and attention allocation to the rare, task-relevant stimuli.
๐ฅ Shin_midterm_part2 - Grace Shin.mp4
๐ก Videos require Google Drive access. Open in new tab if it doesn't load.
๐ฅ Shin_midterm_part1 - Grace Shin.mp4
๐ก Videos require Google Drive access. Open in new tab if it doesn't load.
๐ Shin_midterm_part2 - Grace Shin.txt
๐ก Code is embedded in this portfolio - opens instantly in the live BrainImation editor (no internet required!)
๐ Shin_midterm_part1 - Grace Shin.txt
๐ก Code is embedded in this portfolio - opens instantly in the live BrainImation editor (no internet required!)