eegID

eegID by Isomer Programming LLC enables you to connect over Bluetooth(TM) to a NeuroSky(TM) MindWave Mobile Headset (or others compatible with ThinkGear(TM) technology), and view Electroencephalography (EEG) data, specifically these fields: PoorSignal, EEG Raw Value, EEG Raw Value Volts, Attention Level, Meditation Level, Blink Strength, Delta(1-3Hz), Theta(4-7Hz), Alpha Low(8-9Hz), Alpha High(10-12Hz), Beta Low(13-17Hz), Beta High(18-30Hz), Gamma Low(31-40Hz), and Gamma Mid(41-50Hz). This data can be recorded and stopped at will, or configured with a maximum recording limit (ex: 30min, or 10MB), after which a spreadsheet-importable comma-separated values (CSV) file including time stamps of all signal records listed above is prompted to the user to optionally email as an attachment with a populated subject line containing the current date and time (the Send button allows the last record to be resent after exit). A minimum record interval may also be specified (ex: every 1 minute). During the recording process, a user may select different tags to differentiate internal recording periods. GPS can also be optionally enabled to tag the latitude and longitude for each record. The last recorded eegIDRecord.csv file is located on the external storage device within the folder "eegid"; file extraction via USB connection to a computer may be necessary if your selected recording limit exceeds the standard 10MB email attachment size. Note that the EEG Raw Value Volts is calculated with: [ rawValue * (1.8/4096) ] / 2000. For troubleshooting, also note that the PoorSignal value indicates invalid EEG positioning (adjust device until this is 0 for best results), and that while PoorSignal is greater than 0, some signals are not received (Attention, Meditation, Blink Strength). The purpose of this application is to allow easy mobile EEG data capture with simple immediate measurements and later deep analysis or data storage for reference.

*** If you plan on purchasing a device solely to use with this application, please first send us an email with specifications of the device you intend to use and we can check it for you.

VOLTAGE DATA DETAILS:

eegRawValueVolts (specified in units of Volts) is calculated with: [ eegRawValue * (1.8/4096) ] / 2000. The NeuroSky device has its own range for the initial eegRawValue based on the chip, and this equation is from the NeuroSky documentation to calculate true voltage (make sure you are formatting the value in your spreadsheet correctly to see the full value).

FREQUENCY BAND DATA DETAILS:

Frequency band values are reported directly as received from the NeuroSky SDK and not transformed by the eegID app. These values are unitless integer representations of the percentage span of an adaptive fast fourier transform that is proprietary to NeuroSky, that have a full range from -(2^31) to (2^31)-1. The full range will likely not be evident in tests. Best practices for representing data range percentage using these values is to use a moving average of the minimum and maximum bounds with clamps, or to use the full data set after the fact and use the minimum and maximum range experienced during that data set. If you require mathematical justification, since the exact calculation method is proprietary, it is instead recommended that you do not use these values, and instead that you only use eegRawValueVolts with the setting RecordInterval=All, and that you develop your own mathematical fourier transform method to extract frequency levels from the raw data.

Delta(1-3Hz)

Theta(4-7Hz)

Alpha Low(8-9Hz)

Alpha High(10-12Hz)

Beta Low(13-17Hz)

Beta High(18-30Hz)

Gamma Low(31-40Hz)

Gamma Mid(41-50Hz)

You may find additional supportive documentation on interpreting values at this website:

http://developer.neurosky.com/docs/doku.php?id=mindwave