Safe Haskell	None
Language	Haskell2010

Hemokit

Contents

Opening and reading from EEGs
EEG data
Dealing with (decrypted) raw data
Encrypted raw data
Internals
Interactive use

Description

A library for reading from an Emotic EPOC EEG.

Use getEmotivDevices to list available EEGs.
Use openEmotivDevice to open a device for reading.
Use readEmotiv read from an open device.
You will obtain EmotivPackets and EmotivStates.

Synopsis

Opening and reading from EEGs

_EMOTIV_VENDOR_ID :: VendorID Source

The USB vendor ID of the Emotiv EPOC.

_EMOTIV_PRODUCT_ID :: ProductID Source

The USB product ID of the Emotiv EPOC.

data EmotivDeviceInfo Source

Identifies an Emotiv device.

Constructors

EmotivDeviceInfo
Fields hidapiDeviceInfo :: DeviceInfo The hidapi device info.

Instances

Show EmotivDeviceInfo
Generic EmotivDeviceInfo
NFData EmotivDeviceInfo
type Rep EmotivDeviceInfo

data EmotivRawDevice Source

An "open" data source to read bytes from.

Constructors

HidapiDevice
Fields hidapiDevice :: Device The open hidapi device.
HandleDevice
Fields handleDevice :: Handle A conventional `Handle`, e.g. an open file.

Instances

Generic EmotivRawDevice
type Rep EmotivRawDevice

data EmotivDevice Source

Identifies an open Emotiv device. Also contains the cumulative EmotivState of the EEG.

Constructors

EmotivDevice
Fields rawDevice :: EmotivRawDevice Where we get our data from, some form of "open handle". serial :: SerialNumber The EEG's serial. emotivModel :: EmotivModel Whether the EEG is a consumer or developer model. stateRef :: IORef (Maybe EmotivState) The EEG's cumulative state.

Instances

Generic EmotivDevice
type Rep EmotivDevice

getEmotivDevices :: IO [EmotivDeviceInfo] Source

Lists all EPOC devices, ordered by interface number. If you do not actively choose amongst them, the last one is usually the one you want (especially if only 1 EEG is connected).

openEmotivDevice :: EmotivModel -> EmotivDeviceInfo -> IO EmotivDevice Source

Opens a given Emotiv device. Returns an EmotivDevice to read from with readEmotiv.

openEmotivDeviceFile :: EmotivModel -> SerialNumber -> String -> IO EmotivDevice Source

Creates an EmotivDevice device from a path, e.g. a device like devhidraw1 or a normal file containing dumped binary data.

openEmotivDeviceHandle :: EmotivModel -> SerialNumber -> Handle -> IO EmotivDevice Source

Creates an EmotivDevice device from an open file handle.

readEmotiv :: EmotivDevice -> IO (Maybe (EmotivState, EmotivPacket)) Source

Reads one 32 byte packet from the device, parses the raw bytes into an EmotivPacket and updates the cumulative EmotivState that we maintain for that device.

Returns both the packet read from the device and the updated state.

Returns Nothing on end of input (or if there are < 32 bytes before it).

Note that if the EEG is (turned) off, this function block until it is turned on again.

data EmotivException Source

Emotiv related errors.

Constructors

InvalidSerialNumber SerialNumber	Serial does not have right format.
CouldNotReadSerial DevicePath	We could not read the serial from the device.
OtherEmotivException String

Instances

Data EmotivException
Show EmotivException
Generic EmotivException
Exception EmotivException
NFData EmotivException
Typeable * EmotivException
type Rep EmotivException

data SerialNumber Source

A valid Emotiv serial number. 16 bytes.

Instances

Eq SerialNumber
Ord SerialNumber
Show SerialNumber
Generic SerialNumber
type Rep SerialNumber

makeSerialNumber :: ByteString -> Maybe SerialNumber Source

Checks an Emotiv serial, returning a SerialNumber if it's valid.

makeSerialNumberFromString :: String -> Maybe SerialNumber Source

Like makeSerialNumber, using a String.

deviceInfoSerial :: EmotivDeviceInfo -> Maybe SerialNumber Source

Conveniently expose the serial number of a device.

data EmotivModel Source

Whether the EPOC is a consumer or developer model.

This affects how the EEG data is to be decrypted.

You can check if you are using the correct model by seeing if the packet counter increases from 0 until 128 on subsequent packets.

Constructors

Consumer
Developer

Instances

Eq EmotivModel
Ord EmotivModel
Show EmotivModel
Generic EmotivModel
type Rep EmotivModel

EEG data

data EmotivPacket Source

Contains the data of a single packet sent from the device. Accumulated data (the current state) is available in EmotivState.

Constructors

EmotivPacket
Fields packetCounter :: Int counts up from 0 to 127 (128 Hz) packetBattery :: Maybe Int the current battery percentage packetGyroX :: Int turning "left" gives positive numbers packetGyroY :: Int turning "down" gives positive numbers packetSensors :: Vector Int EEG sensor values packetQuality :: Maybe (Sensor, Int) EEG sensor-to-skin connectivity

Instances

Eq EmotivPacket
Ord EmotivPacket
Show EmotivPacket
Generic EmotivPacket
NFData EmotivPacket
type Rep EmotivPacket

data EmotivState Source

Contains the "current state" of the EEG, cumulateively updated by incoming EmotivPackets.

Constructors

EmotivState
Fields counter :: Int counts up from 0 to 127 (128 Hz) battery :: Int the current battery percentage gyroX :: Int turning "left" gives positive numbers gyroY :: Int turning "down" gives positive numbers sensors :: Vector Int EEG sensor values qualities :: Vector Int EEG sensor-to-skin connectivity

Instances

Eq EmotivState
Ord EmotivState
Show EmotivState
Generic EmotivState
NFData EmotivState
type Rep EmotivState

data Sensor Source

The sensors of an Emotiv EPOC. Uses the names from the International 10-20 system.

Constructors

F3
FC5
AF3
F7
T7
P7
O1
O2
P8
T8
F8
AF4
FC6
F4

Instances

Bounded Sensor
Enum Sensor
Eq Sensor
Ord Sensor
Show Sensor
Generic Sensor
NFData Sensor
type Rep Sensor

allSensors :: [Sensor] Source

Contains all Sensors.

Dealing with (decrypted) raw data

newtype EmotivRawData Source

Wraps (unencrypted) Emotiv raw data. Ensures that it is 32 bytes.

Constructors

EmotivRawData
Fields emotivRawDataBytes :: ByteString

Instances

Eq EmotivRawData
Ord EmotivRawData
Show EmotivRawData
Generic EmotivRawData
NFData EmotivRawData
type Rep EmotivRawData

readEmotivRaw :: EmotivDevice -> IO (Maybe EmotivRawData) Source

Reads one 32 byte packet from the device and decrypts it to raw data.

Returns Nothing on end of input (or if there are < 32 bytes before it).

Note that if the EEG is (turned) off, this function block until it is turned on again.

makeEmotivRawData :: ByteString -> EmotivRawData Source

Treat a ByteString as Emotiv raw data. Errors if the input is non 32 bytes.

parsePacket :: EmotivRawData -> EmotivPacket Source

Parses an EmotivPacket from raw bytes.

updateEmotivState :: EmotivDevice -> EmotivRawData -> IO (EmotivState, EmotivPacket) Source

Given a device and a Emotiv raw data, parses the raw data into an EmotivPacket and updates the cumulative EmotivState that we maintain for that device.

Care should be taken that raw data is fed into this function in the right order (e.g. respecting the EEG's increasing sequence numbers and quality updates).

This function is only neededif you want to obtain both raw data and parsed packages. If you are not interested in raw data, use readEmotiv instead.

Returns both the packet read from the device and the updated state.

Encrypted raw data

decrypt :: SerialNumber -> EmotivModel -> ByteString -> EmotivRawData Source

Takes a 32 bytes encrypted EEG data, returns 32 bytes decrypted EEG data.

Internals

newtype BitMask Source

Describes the indices of bits to make up a certain value.

Constructors

BitMask [Word8]

Instances

Eq BitMask
Ord BitMask
Show BitMask

getSensorMask :: Sensor -> BitMask Source

Describes which bits in a raw data packet make up the given sensor.

qualityMask :: BitMask Source

Describes which bits in a raw data packat make up a sensor quality value.

getLevel :: EmotivRawData -> BitMask -> Int Source

Extracts the sensor value for the given sensor from Emotiv raw data.

batteryValue :: Word8 -> Int Source

Parses a battery percentage value from a byte.

qualitySensorFromByte0 :: Word8 -> Maybe Sensor Source

Which sensor's quality is transmitted in the packet (depends on first byte, the packet counter).

Interactive use

withDataFromLastEEG :: EmotivModel -> ((EmotivState, EmotivPacket) -> IO ()) -> IO () Source

Opens and reads from the last available device, giving all data from it to the given function. Stops if end of input is reached.

Intended for use with ghci.

Examples:

withDataFromLastEEG Consumer print
withDataFromLastEEG Consumer (print . packetQuality . snd)
withDataFromLastEEG Consumer (putStrLn . unwords . map show . V.toList . qualities . fst)