emotiv.py

try:
	import pywinusb.hid as hid
	windows = True
except:
	windows = False

import sys, os
import logging
logger = logging.getLogger("emotiv")

from aes import rijndael
import struct

from threading import Thread

consumer_key = '\x31\x00\x35\x54\x38\x10\x37\x42\x31\x00\x35\x48\x38\x00\x37\x50'
research_key = '\x31\x00\x39\x54\x38\x10\x37\x42\x31\x00\x39\x48\x38\x00\x37\x50'

sensorBits = {
	'F3': [10, 11, 12, 13, 14, 15, 0, 1, 2, 3, 4, 5, 6, 7], 
	'FC6': [214, 215, 200, 201, 202, 203, 204, 205, 206, 207, 192, 193, 194, 195], 
	'P7': [84, 85, 86, 87, 72, 73, 74, 75, 76, 77, 78, 79, 64, 65], 
	'T8': [160, 161, 162, 163, 164, 165, 166, 167, 152, 153, 154, 155, 156, 157], 
	'F7': [48, 49, 50, 51, 52, 53, 54, 55, 40, 41, 42, 43, 44, 45], 
	'F8': [178, 179, 180, 181, 182, 183, 168, 169, 170, 171, 172, 173, 174, 175], 
	'T7': [66, 67, 68, 69, 70, 71, 56, 57, 58, 59, 60, 61, 62, 63], 
	'P8': [158, 159, 144, 145, 146, 147, 148, 149, 150, 151, 136, 137, 138, 139], 
	'AF4': [196, 197, 198, 199, 184, 185, 186, 187, 188, 189, 190, 191, 176, 177], 
	'F4': [216, 217, 218, 219, 220, 221, 222, 223, 208, 209, 210, 211, 212, 213], 
	'AF3': [46, 47, 32, 33, 34, 35, 36, 37, 38, 39, 24, 25, 26, 27], 
	'O2': [140, 141, 142, 143, 128, 129, 130, 131, 132, 133, 134, 135, 120, 121], 
	'O1': [102, 103, 88, 89, 90, 91, 92, 93, 94, 95, 80, 81, 82, 83], 
	'FC5': [28, 29, 30, 31, 16, 17, 18, 19, 20, 21, 22, 23, 8, 9]
}

class EmotivPacket(object):
	def __init__(self, data):
		self.counter = ord(data[0])
		self.sync = self.counter == 0xe9
		self.gyroX = ord(data[29]) - 102
		self.gyroY = ord(data[30]) - 104
		#assert ord(data[15]) == 0
		
		for name, bits in sensorBits.items():
			level = 0
			for i in range(13, -1, -1):
				level <<= 1
				b, o = (bits[i] / 8) + 1, bits[i] % 8
				level |= (ord(data[b]) >> o) & 1
			strength = 4#(ord(data[j]) >> 3) & 1
			setattr(self, name, (level, strength))
	
	def __repr__(self):
		return 'EmotivPacket(counter=%i, gyroX=%i, gyroY=%i)' % (
				self.counter, 
				self.gyroX, 
				self.gyroY, 
			)

class Emotiv(object):
	def __init__(self, headsetId=0, research_headset = True):
		
		if research_headset:
			self.rijn = rijndael(research_key, 16)
		else:
			self.rijn = rijndael(consumer_key, 16)
		
		self._goOn = True
		self.packets = []
		
		if self.setupWin(headsetId) if windows else self.setupPosix(headsetId):
			logger.info("Fine, connected to the Emotiv EPOC receiver")
		else:
			logger.error("Unable to connect to the Emotiv EPOC receiver :-(")
			sys.exit(1)
	
	def setupWin(self, headsetId):
		filter = hid.HidDeviceFilter(vendor_id=0x21A1, product_name='Brain Waves')
		devices = filter.get_devices()
		assert len(devices) > headsetId
		self.device = devices[headsetId]
		self.device.open()
		def handle(data):
			assert data[0] == 0
			self.gotData(''.join(map(chr, data[1:])))
		self.device.set_raw_data_handler(handle)
		return True
	
	def setupPosix(self, headsetId):
		def reader():
			_os_decryption = False
			if os.path.exists('/dev/eeg/raw'):
				#The decrpytion is handled by the Linux epoc daemon. We don't need to handle it there.
				_os_decryption = True
				self.hidraw = open("/dev/eeg/raw")
			else:
				if os.path.exists("/dev/hidraw2"):
					self.hidraw = open("/dev/hidraw2")
				else:
					self.hidraw = open("/dev/hidraw2")
			
			while self._goOn:
				data = self.hidraw.read(32)
				if data != "":
					if _os_decryption:
						self.packets.append(EmotivPacket(data))
					else:
						#Decrypt it!
						self.gotData(data)
					
		self._dataReader = Thread(target=reader)
		self._dataReader.start()
		return True
	
	def gotData(self, data):
		assert len(data) == 32
		data = self.rijn.decrypt(data[:16]) + self.rijn.decrypt(data[16:])
		self.packets.append(EmotivPacket(data))
	
	def dequeue(self):
		while len(self.packets):
			yield self.packets.pop(0)
	
	def close(self):
		if windows:
			self.device.close()
		else:
			self._goOn = False
			self._dataReader.join()
			
			self.hidraw.close()