26-06-2012, 01:42 PM
Emerging Technology for Brain Machine Interface
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INTRODUCTION
The brain is the major organ of the central nervous system and the control centre for all the body’s voluntary and involuntary activities. One of the major parts of the brain is cerebellum whose main functions are the maintenance of posture and the coordination of body movements.
In the human body there are several parts and all having its separate motion. Each area of the cerebellum has its separate significance in the body movements.
To control movement the brain has several parallel systems of muscle control. The motor system controls voluntary muscle movement, aided by the motor cortex cerebellum, and the basal ganglia. The picture below shows the cerebellum with clear labelelling showing at which part, signals are generated for controlling, which body parts.
EXISTING SYSTEM
Presently research is going on in the field of signal extraction from the brain. This extracted signal is being experimented with various applications like artificial arm, artificial eye, artificial ear etc. This paper has focused on one similar application in the form of a wheel chair, which will be useful for persons with total neural failure and other degenerative neural disorders, with an experimental setup to simulate the extraction of brain signal.
MOTIVATION
Ron Nuzzie a salesman was paralyzed neck below in a major car accident. The doctors in the intensive care unit were able to save his life but he was declared a quadriplegic [3]. No current available technologies could give him full solace. This spurred us to think of the brain-controlled wheel chair, a major application of brain machine interface technology.
PROPOSED SYSTEM
.Extraction of Brain Signals
The data-out BMI consists of multi-neuron population recordings in motor cortex, the output of which is electronically decoded. The neural implants typically consist of a four by four millimeter multi-electrode (25-100+ electrode) array that is implanted into the area of motor cortex that is most active during the motor task of interest (such as moving an arm). Data-out BMIs are a recent phenomenon because they involve several technological feats that are of recent origin: predicting (via FRMI) where the motor activity of interest occurs, the ability permanently implant single cell recording devices into the motor cortex, and the ability to make mathematical and mechanical sense of the neural output in the short time period necessary for such control. Newer, blunt-tipped, flexible, Teflon-coated stainless steel microwires produce very little damage and allow permanent implantation.
WORKING MODEL
Fig. 4 shows block diagram of the working model. In this, a scaled down implementation has been done. Inputs in the form of voltage are given to operate stepper motor and LED’s, which are controlled by a microcontroller. Three inputs are given to the microcontroller. But in real time applications parallel processes require multiple microcontrollers but in this design one microcontroller performs three different operations sequentially but gives an image of parallel operation. The input (voltage) responsible for leg movement is given to an A/D converter also.
IMPLEMENTATION DETAILS
The voltage input is given to the 8051 microcontroller and for leg case it is given to the A/D converter also. Based on the voltage given, the A/D converter gives a corresponding digital value, which is given as an interrupt to the microcontroller. The following is the program loaded in the microcontroller. The program checks whether there is a input in the port p2.0, if the bit is not set the control goes to the next, otherwise the control is transferred to the hand routine. There it sets the port p3.0, which enables the output device connected, and then the control returns. Here it checks for the input in port p2.1, if the bit is not set the control flow goes to the next, otherwise the control is transferred to the eye routine. There it sets the port p3.1, which enables the external device connected, and then the control returns.
. FUTURISTIC APPLICATIONS
One possible frightening application of brain machine interface technology is data interpretation were a persons brain contents can be interpreted by interfacing the brain to computers. This has practical applications were police could use this technology to extract secrets from criminals. Direct control of vehicles, computers, phones etc can be done using brain interface without use of our hands and exertion of energy. Futuristic war fares where the soldiers can operate the war weapons and vehicles sitting in some place thousands of miles from the actual place of war. This technology is so futuristic that a person can actually carry out businesses, travel etc without as much as twitching a muscle.
CONCLUSION
Brain machine interface is an emerging technology that is undergoing through a sea of research. It extracts signals directly from the brain thus circumventing the spinal cord and thereby giving spinally injured persons a go at normal life. In this paper the technology has been taken a step further with the design of the BCW that provides mobility to persons with motor immobility. Like any major technology, brain interface has its drawbacks, shortcomings and dangers but it is a technology for the future.