BrainAccess MINI​

The BrainAccess MINI is an 8-channel electroencephalograph with a common reference channel.

Its compact size, Bluetooth connectivity, and long battery life make it a truly portable device.


USB Bluetooth adapter

The device comes with a USB Bluetooth 4.2 adapter, which is used to communicate and stream data to the computer from BrainAccess MINI. If preferred, a different Bluetooth adapter such as an integrated Bluetooth adapter in a laptop may be used instead.

Power switch

Press and hold a push-button for a couple of seconds to turn the device on/off. The power LED will be lit when powered on.

Charging port

The device's battery can be charged via a micro-USB port using standard 5V chargers such as mobile phone chargers with a micro-USB plug. The charger should be capable of providing at least 800 mA of current. Do not use the device when charging with chargers powered from grid electricity due to safety reasons and potentially 50/60 Hz noise affecting the signals. The device can be used when charging from a power bank though.

Power LED

It is a red-colored LED that indicates when the device is powered on. If the power LED starts blinking, it indicates that the battery level is below 10% and needs charging soon.

Connection LED

It is a blue-colored LED that indicates when a Bluetooth connection is established between a computer and the device.

EEG inputs

These inputs should be connected to electrodes that measure EEG activity with respect to the reference electrode.

Reference input

An input that should be connected to a common reference electrode. In BrainAccess Kit setups it is typically an electrode placed at the Fp1 location. The connection is denoted as 'R' on the device.

Bias input

An input that should be connected to a bias electrode. In BrainAccess Kit setups it is typically an electrode placed at the Fp1 location. The connection is denoted as 'B' on the device. It is a driven bias that reduces the common mode noise such as noise coming from the grid electricity. The bias signal is derived from any of the EEG inputs which can be chosen in software. They are denoted as 'bias feedback channels' in software. Use only channels/electrodes that have good-quality signals for bias feedback.

Digital input

The device has an additional digital input that is sampled at the same rate as EEG signals and is treated as an additional input channel in software. It can be used for connecting external sensors or for synchronizing multiple BrainAccess MINI devices. The digital input is internally pulled high and is driven low when input contacts are closed. An external switch or open-collector/open-drain circuits can be used to close the digital input contacts and drive the digital signal low.


Our EEG hardware device has an integrated 3-axis accelerometer. It can be used for example to record any body/head movements when it is attached to the EEG headwear. The accelerometer data comes as 3 additional input channels in the software.

Velcro tape attachment

A velcro tape can be found at the bottom of the device that can be used to attach it to the BrainAccess CAP.


Specifications of BrainAccess MINI electroencephalograph.



Bluetooth 4.2


up to 10m (using the provided Bluetooth adapter)

EEG Input Channels

Number of channels

8 with a common reference channel

Sampling frequency

250 Hz

Input resolution

24 bits

Analog gain values

1, 2, 4, 6, 12, 24

Input voltage range

4500 mV / gain value (w.r.t. reference channel)

Input connector

Ultra-mini RF coaxial connector

Digital Input Channel


internally pulled-up, driven low by closing the input contacts

Sampling frequency



JST right-angle, 2 mm pitch, cable with a plug also provided


Number of axis


Sampling frequency

50Hz (resampled to 250Hz in software)




10 bits





1500 mAh

Operating time

up to 6 hours (continuous streaming, all channels turned on)

Charging time

2 hours

Charger input

5V 800 mA min (charger not included)

Charger connector






68x50x21 mm