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TR5.....MIND SWITCH - THINK APPLIANCES ON, OFF, OR ADJUST

Original link (March 2000):
http://www.phys.uts.edu.au/~asearle/mind_switch/m_switch.html

OVERVIEW

The Mind Switch refers to the technology that has been
developed which allows a person to turn on and off an
electrical appliance, such as a desk lamp or TV in 2-3 seconds
using EEG signals, without training. Proportional control,
such as turning up or down the volume of a radio is also
possible with the technology. This research is being carried
at the University of Technology, Sydney (UTS).


BACKGROUND - General

Early in 1994 while studying the response of the brain to
environmental factors Professor Ashley Craig and Mr Paul
McIsaac of the Department of Health Sciences at UTS, noticed
an effect which appears to be common among all persons. That
effect is an increase in a particular brain signal when a
person closes his/her eyes for more than one second. The
important question that Ashley and Paul then asked was could
this effect be used to do something useful?, ie - could the
control of the brain signal be used, in turn, to control
something else?

At this stage Ashley contacted Professor Tony Moon, the Dean
of Science at UTS, to find out if anyone could help answer the
technical questions and design a system that might exploit the
apparent change in the signal level when a person closes
his/her eyes. Professor Moon introduced Ashley to Assoc Prof
Les Kirkup who is a associate professor in the department of
Applied Physics at UTS, who has experience in developing
electronics and instrumentation.

It was thought he could offer important input to the project.
He was initially sceptical that signals as small as those that
are present on the scalp, (where electrodes are placed to pick
up brain activity) could be detected reliably and analysed
sufficiently quickly to allow activation of an external
device, such as a lamp or TV. The data that had been gathered
on signal levels with eyes open and eyes closed showed that a
significant increase occurred in the 8-13Hz part of the 'brain
spectrum' commonly referred to as the 'alpha' region.

Les built a detection, discrimination and analysis system
based on Ashley and Paul's data and, much to his surprise at
least, the first person (Lucy) connected to the system showed
the capability of operating a switch which could control an
electrical appliance.


BACKGROUND - Technical

Serious work done on brain signals began with Berger in 1929
[Berger 1967]. Since that time the acquisition and analysis of
brain signals, referred to as Electroencephalography (EEG) has
advanced to such a state that EEG is regularly used to assist
in the diagnosis of schizophrenia, epilepsy and brain tumours.
[Geddes and Baker, 1989]. EEG has also been used in
biofeedback studies in which subjects may learn to modify
their EEG signals in response to visual representation of
their EEG signals.

This control usually take weeks or months to learn and is not
highly reliable. The system we have developed does NOT rely on
any learned skill by an individual. It simply requires a
person to close his/her eyes for more than 1 second to effect
sufficient change in the signals levels to allow for the
reliable operation of a switch. It turns out that it has been
known for many years that increase in signal level occur upon
eye closure, but this is the first example (to our knowledge)
of the recognition of its potential and the exploitation of
the effect.

The system used to detect the change in signals consists of
amplifiers, filters and other signal processing elements (full
DETAILS ARE STILL CLASSIFIED at the moment!). As there are
other sources which can generate signals which can interfere
with brain signals (and hence cause intermittent switching on
and off of appliances) we have developed a noise suppression
system which eliminates the effect of those noise sources.
This feature is very important as we are currently developing
the technology for disabled persons (we have a three year
grant from the Motor Accident Authority of New South Wales,
MAA) and reliability is a major issue. The funding from MAA
has allowed us to appoint Mr Andrew Searle who has become a
key figure in the technical developments regarding the Mind
Switch.

In addition Mr Perez Moses is developing new noise suppression
techniques to be applied in this work.

Berger, H. 1967. On the electroencephalogram of man (trans. by
P. Gloor).EEG Clin.  Neurophysiol., Suppl. 28:1-350

Geddes, L. A. and Baker, L. E. 1989. Principles of applied
biomedical instrumentation 3rd ed.  (Wiley, New York):
pp726-727