Int. J. Biomedical Engineering and Technology, Vol. 11, No. 2, 2013 197 Copyright © 2013 Inderscience Enterprises Ltd. Brain–computer interface: a thought translation device turning fantasy into reality Aruna Tyagi* and Vijay Nehra Department of Electronics & Communication Engineering, School of Engineering and Sciences, Bhagat Phool Singh Mahila Vishwavidyalaya, Sonepat, Haryana, India Email: aruna007_tyagi@yahoo.co.in Email: Nehra_vijay@yahoo.com *Corresponding author Abstract: Brain–Computer Interface (BCI) provides an alternate means of communication to the people who have lost control of their body due to some neuromuscular disorder and a new modality for control to healthy people. BCI detects changes in brain activity and encodes brain signals into commands to control an application of interest. Brain activity can be recorded in the form of electrophysiological signals, magnetic signals or metabolic signals. A BCI system detects, processes, identifies and classifies the brain signals and then translates these neural signals into commands. This paper discusses current state of art of BCI research, emphasises on its applications and considers various issues and challenges which make it difficult to move BCI technology from labs to home. Keywords: brain-computer interface; electroencephalography; sensorimotor rhythms; slow cortical potentials; steady state visual evoked potentials; signal processing; neuroprosthesis; mind controlled games. Reference to this paper should be made as follows: Tyagi, A. and Nehra, V. (2013) ‘Brain–computer interface: a thought translation device turning fantasy into reality’, Int. J. Biomedical Engineering and Technology, Vol. 11, No. 2, pp.197–211. Biographical notes: Aruna Tyagi is currently a PhD scholar at the Department of Electronics and Communication Engineering, School of Engineering and Sciences, Bhagat Phool Singh Mahila Vishwavidyalaya, Khanpur, Sonepat, Haryana, India. Her research area includes digital signal processing and brain– computer interface. Vijay Nehra is currently an Associate Professor and Ex. Dean and Head at the Department of Electronics and Communication Engineering, School of Engineering and Sciences, Bhagat Phool Singh Mahila Vishwavidyalaya, Khanpur, Sonepat, Haryana, India. He holds PhD in Electronics. His research area includes signal processing, plasma electronics. He has contributed research papers in refereed national and international journals. 1 Introduction Brain–Computer Interface (BCI) is basically a thought translation device which provides a link between the brain and the physical world without any physical contact. BCI is an