13-05-2013, 02:56 PM
APPLIANCE SWITCHING USING EYE MOVEMENT FOR PARALYZED
PEOPLE
APPLIANCE SWITCHING.pdf (Size: 1.59 MB / Downloads: 53)
ABSTRACT
Paralysis is loss of muscle function, loss of feeling (sensory loss) in one or more affected areas.
If there is sensory damage as well as motor & such people suffer from Motor Neuron Disease. In
other words these people are in near vegetative state with only their eyes moving. Such people
are completely dependent on other individuals for all of their work, starting from feeding to
general change in position. So, a system needs to be developed to help these people to become
independent. There are systems available in the market that are developed to help paralyzed
people in some way or the other, but they are limited to only those people who are only partially
paralyzed, that means, fully paralyzed people have little or no use of these systems. Also, these
systems are very costly, bulky & less portable. Our system will be cost effective, portable &
moreover it will help even those people who are completely paralyzed with only their eyes
moving. This system will be based on only the movement of the eyes hence eliminating the need
of any limb or any other body movements.
INTRODUCTION
Eye tracking is a technique whereby an individual’s eye movements are measured so that
the researcher knows both where a person is looking at any given time and the sequence in which
their eyes are shifting from one location to another. The annual report of the Ministry of Public
Health and Welfare states that 0.73 million people have a motor disability on the legs and arms.
For people with these disabilities, many different kinds of activities like switching fan, tubelight,
etc. on/off become very problematic due to restricted movements of these body parts.
These people are dependent on others for switching any home devices whenever they want to.
Conversion of Sensor Output into Digital Form:-
The RF module requires data serially and it also gives back the data serially. Hence it
requires some assembly which converts the three or four bits of data acquired from the
conversion mechanism to a sequence of serial data. As per our requirement, it is also necessary
that this data should not be corrupted by any intervention of the same frequency. This means that
we also must have some pre-sequence of at least three bits which is predefined, and this
sequence should be checked at the decoder side to validate the data. All this can be taken
care of by the ADC (Analog-to-Digital) of microcontroller PIC16F877A.
The input to this ADC is the analog voltage signal from the corresponding LDR. Since
we have used 2 LDRs, there will be two voltage signals (one from each LDR) applied to the two
corresponding input pins of ADC. The converter then generates a digital result of this analog
level via successive approximation. The A/D conversion of the analog input signal results in a
corresponding 10-bit digital number. That means the output of the ADC will be in terms of ‘1’s
and ‘0’s. This output is given to RF transmitter which is CMOS compatible & hence don’t
require line driver like MAX232.
Data Transmission Module
After digital data has been made from the iris movement, this data needs to be transmitted
without any error to a distant place, preferably near to the switchboards already installed in the
room wirelessly. Wireless transmission is preferred to wired transmission here to avoid a jumble
of wires spreading across the room. A point to be noted is that it is more economic to use wires if
the switchboard is nearby. But wires may become inconvenient for the user in most cases.
Decision Making Section
The decision making block processes on the data available to it from the RF receiver. The
microcontroller PIC16F877A is used for this purpose, where the main job of the controller is to
make certain decisions according to the available data and send its decisions to the relay board.
In addition to data processing, the microcontroller also double checks any false triggering, takes
into account the delay caused due to wireless channel and checks whether the transmission is
valid or not.
Depending on the intensity of light reflection from eyes, microcontroller makes the
decision on which of the devices (connected at output) will toggle its state depending on the
program. Here, we have program the microcontroller in such way that if LDR1 gets stronger
reflections, Relay 1 will be activated whereas LDR2 gets stronger reflections, Relay 2 will be
activated.
COMPARISON
Our system is basically based on the system in [1]. But our system has some major
differences compared to the above system. System [1] uses photodiode sensors whereas we have
used LDR due to easy availability. This is done because of we already had a set of LDRs
available with us. Although, using photodiodes will give good results. The signal conditioning
circuit is required for system [1], but our system does not require any signal conditioning since
o/p of sensor is suitable enough for further processing. Due to this, our system is less bulky.
System [1] uses different modules for encoding, decoding, data transmission & reception,
CONCLUSION
Right from the sensor module to the output, each module is working as expected. Our
endeavor of the semester is successful Light Dependent Diode (LDRs) work well for good light
intensity but not in poor light conditions.
A way still needs to be found to reduce the dependence on ambient light. Attempts were
also made to make the output of the device more reliable. But due to lack of time, funds we are
restricted to very few attempts.
This system can further be made more accurate, work in ‘real world’ by making some
optimizations. Few are listed below:-
• We can use IR sensors to get more accurate output.
• We can create a Graphical User Interface (GUI) with visual and sound effects, so that it
would be very easy and user-friendly device.
• We can make the data transmission more accurate & secure by using Xigbee (due to
high cost of Xigbee as compared to CC2500; we have avoided using it & used CC2500
instead).