BrainAccess MAXI

BrainAccess MAXI is a 32-channel electroencephalograph with a common reference channel. It has the same form factor and the same EEG input connector as the MIDI device but offers double the number of EEG input channels. Both 16 and 32-electrode BrainAccess caps can be used interchangeably with a MAXI 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 MIDI. 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. Note: the device cannot be used while charging.

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.

Input connector

It is a convenient connector to quickly connect/disconnect BrainAccess CAP when switching between different sizes or configuration caps. It is also compatible with both 16 or 32-electrode BrainAccess CAPs.


The 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 cap. 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 MIDI electroencephalograph.



Bluetooth 4.2


up to 10m (using the provided Bluetooth adapter)

EEG Input Channels

Number of channels

32 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

Harting Har-flex 2 x 20 1.27mm pitch


Number of axis


Sampling frequency

50Hz (resampled to 250Hz in software)




10 bits





2200 mAh

Operating time

up to 9 hours (continuous streaming, all channels turned on)

Charging time

3 hours

Charger input

5V 800 mA min (charger not included)

Charger connector






92x50x23 mm