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Experimental Brain Research (2021) 239:3573–3583
https://doi.org/10.1007/s00221-021-06231-4
RESEARCH ARTICLE
Low‑cost brain computer interface foreveryday use
IldarRakhmatulin1 · AndreyParfenov2· ZacharyTraylor3· ChangS.Nam3· MikhailLebedev4
Received: 27 June 2021 / Accepted: 21 September 2021 / Published online: 29 September 2021
© The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature 2021
Abstract
With the growth in electroencephalography (EEG) based applications the demand for affordable consumer solutions is
increasing. Here we describe a compact, low-cost EEG device suitable for daily use. The data are transferred from the
device to a personal server using the TCP-IP protocol, allowing for wireless operation and a decent range of motion for the
user. The device is compact, having a circular shape with a radius of only 25mm, which would allow for comfortable daily
use during both daytime and nighttime. Our solution is also very cost effective, approximately $350 for 24 electrodes. The
built-in noise suppression capability improves the accuracy of recordings with a peak input noise below 0.35μV. Here, we
provide the results of the tests for the developed device. On our GitHub page, we provide detailed specification of the steps
involved in building this EEG device which should be helpful to readers designing similar devices for their needshttps://
github. com/ Ildar on/ ironb ci.
Keywords Brain computer interface (BCI)· EEG· Signal processing· ironbci· Low-cost BCI· Low-cost EEG
Introduction
Electroencephalography (EEG) is one of the most popular
methods for researching the brain; it functions via recordings
of neural activity using the electrodes placed on a subject’s
scalp. The information obtained via EEG is used for vari-
ous purposes, including research and clinical applications.
Many manuscripts in the field of EEG signal processing
even attempt to diagnose diseases with the use of informa-
tion received from EEG electrodes. For example, Kanda
etal. (2017) used the alpha rhythm of the brain (7–13Hz
signals) to improve the discrimination of mild Alzheimer’s
disease. Tylová etal. (2018) used an unbiased estimation of
permutation entropy for EEG analysis. Yu etal. (2018) used
the permutation disalignment index to research the func-
tional brain connectivity in Alzheimer’s disease patients.
More recently, Asadzadeh etal. (2020) presented a com-
plete review of brain pathologies based on EEG signals and
source localization.
Various types of electrode sensors can be used to “meas-
ure EEG signals, including but not limited to wet, contact,
and non-contact”. The highest quality signal is usually
obtained with disposable wet sensors due to their low imped-
ance: in some systems as high as 200 kOhm before applying
the “wet” conductive gel and as low as 5 kOhm after apply-
ing the gel (Lopez-Gordo 2014). One disadvantage of using
wet electrodes, however, is the impedance drift as the gel
dries, which introduces significant changes in the measured
signal. The usage of electrode gel also requires a great deal
of set-up time, and results in the patient needing to wash
the gel out of their hair after the experiment. Obtaining an
EEG signal with a dry contact electrode on the other hand
is a more comfortable way to obtain information about the
functioning of the human brain, as it avoids the mess of the
electrode gel and the set-up/take-down time associated with
cleaning the electrodes and the participant. Unfortunately,
this method is not the most reliable and not suitable for all
scenarios. A relatively high-contact impedance, due to insuf-
ficient electrical connection at the electrode–scalp interface,
Communicated by Bill J Yates.
* Ildar Rakhmatulin
ildar.o2010@yandex.ru
1 South Ural State University, Chelyabinsk, Russia
2 Brainflow, Moscow, Russia
3 Edward P. Fitts Department ofIndustrial andSystems
Engineering, North Carolina State University, Raleigh, NC,
USA
4 Skolkovo Institute ofScience andTechnology, Moscow,
Russia
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