Microsoft Word - 20 APPLIANCE SWITCHING USING EYE MOVEMENT FOR PARALYZED PEOPLE.docx

International Journal of Electronics and Communication Engineering & Technology (IJECET), ISSN 0976 6464(Print), ISSN 0976 6472(Online) Volume 3, Issue 3, October- December (2012), IAEMESeminar report 2013Appliance switching using eye movement for paralyzed people Chapter 1INTRODUCTIONMany of the practical difficulties faced by people with disabilities can be addressed through assistive technology. Engineers who are not directly involved in the disability sector should be aware that by designing devices, environments, and amenities so that they are accessible to people with the widest range of abilities, they can promote greater equality of opportunity in education, employment, and citizenship for disabled people.Engineering academia plays a part in increasing societal equality for people with disabilities. The primary benefit of disability-related projects in engineering education is often portrayed as technological outcomes. Unfortunately, only a small minority of such projects translate directly into actual innovative assistive technology products that become widely available to the people who can benefit. More frequently, projects contribute to future developments indirectly through academic publication. In the experience of those involved in this laboratory, an important benefit of the majority of these projects has been the lasting impact on the student engineers who undertook them, giving them a better understanding of the humanitarian role of engineering.1.1 Humanitarian Engineering in ActionPeople with disabilities tend to be marginalized in many societies, frequently being prevented from accessing public services and amenities, or being deprived of the opportunity to work despite the availability of jobs to which they are well suited. Many are even prevented from expressing themselves freely. In some of the world's most prosperous nations, assistive technology that could facilitate a reasonable level of independence for people with disabilities is simply not available to them. Engineers have the means to create a more level playing field, a society in which people with disabilities can participate fully, as they are entitled to do. By developing and providing appropriate technology and by promoting inclusive designs of devices, environments and services, engineers can help to build a more inclusive society.

1.2 Disability and Design

Disability is often perceived as something "wrong" with a person. This viewpoint sees "disability" as stemming from a medical diagnosis and is often referred to as themedical model, as opposed to thesocial modelof disability. This model proposes that disability is primarily defined not by a person's medical condition, but by the prejudices and exclusionary practices of society. Encouraging students to appreciate the significance of the social model of disability can be a challenge for engineering academics teaching in disability-related subjects.There are manyequipment in existence to assist the disabled people, like reading machines, walking instruments, kitchen equipment etc. These systems are available in themarket 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. Some pictures of the system are given below.

Fig 1. 2.Reaching aidFig 1.1 Walking stick

1.3 The proposed system

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. The technology that is used here is the eye movement technology, which promotes the advanced eye tracking systems.1.4 Eye tracking

Eye trackingis the process of measuring either the point ofgaze(where one is looking) or the motion of an eye relative to the head. Aneye trackeris a device for measuring eye positions andeye movement. Eye trackers are used in research on thevisual system, in psychology, incognitive linguisticsand in product design. There are a number of methods for measuring eye movement. The most popular variant uses video images from which the eye position is extracted. Other methods usesearch coilsor are based on theelectrooculogram. Since 2005, eye tracking is used in communication systems for disabled persons: allowing the user to speak, send e-mail, browse the Internet and perform other such activities, using only their eyes.[38]Eye control works even when the user has involuntary movement as a result ofCerebral palsyor other disabilities, and for those who have glasses or other physical interference which would limit the effectiveness of older eye control systems.1.5 Advantages Fully Paralyzed people can use it very easily. One of the key feature is that the system is cost effective and portable. This system is less bulky and moreover reduces programming efforts since all functions are performed by same module. It has got advantageable operation speed and good functionality, since it uses PIC16F877A This system is based only on the movement of Eye, thateliminates the need of any other body movements. This system will not cause any harm to the user. This system works on wireless networking, so that we can avoid a jumble of wires spreading across the room. This system is small in size so that it can be implemented in spectacles itself. This system does not require any signal conditioning since o/p of sensor is suitable enough for further processing.Chapter 2BLOCK DIAGRAM OF TRANSMISSION SECTION

Fig. 2.1: Block diagram of Transmission Section

2.1 Eye Sensing MechanismRequirements of sensing apparatus:- The sensor should be able to detect minute changes in the movement of the iris. It should have minimum or no dependence on ambient light. Sensor placement should not depend upon the size of the iris. It should give maximum states with minimum movement of eye. It should have minimum eye fatigue, and should not harm the eye. What can we use to sense the movement of the eye Can we use the lens of a camera which produces the image of the eye and then detect its motion? A digital camera circuit is a possible solution to the sensing problem. It has less dependence on ambient light and can detect minute movements of the eye. But the circuit is expensive to make and is complex for its requirement of rapid transmission of large data. There must be a simpler, cheaper and yet exquisite solution of the problem. LDRs are used for sensing the movement of the eye. It measures the reflected intensity of light by varying its resistance according to the light intensity incident on it. When the light intensity increases, it resistance decreases and vice-versa. LDR then converts it into voltage so that ADC of microcontroller can measure it. In reality, the normal eye movement without fatigue is the left and right movement only. The up movement of the eye, if done for more times, introduces fatigue to the eye. So it is preferable not to use the upward movement of the eye for control. In this system, we have used 2 LDRs which are positioned as- one to the left of the eyeball & another one to the right of eyeball-as shown in following figure:-

Fig. 2.2:Positions of two LDRs with respect to eyeNow, we know that the visible portion of the eye has two parts namely white portion (called sclera in medical terminology) and the coloured portion (pertaining to the iris). These white and black parts of the eye have difference in the way they reflect light. The white sclera reflects most of the light falling on it, while the coloured iris will not reflect light with so much intensity. This intensity difference in the reflected light gives us our sensing mechanism. For the left-right movement of the eye, we have 2 cases:- Case 1:- When the eyeball is rotated towards left

Fig. 2.3: Position of Focus of LDRs when eye is turned left

In this case, as seen from fig. 2.3, the focus of LDR1 moves on the black iris area of the eye while the focus of LDR2 is white sclera region. Since, black iris will absorb much of the incident light, the intensity of light reflected towards LDR1 will be less. And the intensity of light reflected towards LDR2 will be greater. So, the o/p voltage from LDR 1 will be more & o/p voltage of LDR2 will be greater (The maximum voltage from both LDRs will be same & the threshold levels of LDRs are equal to their maximum voltages). Hence, device corresponding to LDR2 will get toggled.

Case 2:- When the eyeball is rotated towards right

Fig. 2.4: Position of Focus of LDRs when eye is turned right

In this case, as seen from fig. 2.4, the focus of LDR1 moves on the black iris area of the eye while the focus of LDR2 is white sclera region. Since, black iris will absorb much of the incident light, the intensity of light reflected towards LDR1 will be greater. And the intensity of light reflected towards LDR2 will be less. So, the o/p voltage from LDR2 will be more & o/p voltage of LDR2 will be greater. Hence, device corresponding to LDR1 will get toggled.

Table 2.1: Truth Table for LDR1 & LDR2 2.1.1 LDRLDRs or Light Dependent Resistors are very useful especially in light/dark sensor circuits. Normally the resistance of an LDR is very high, sometimes as high as 1000 000 ohms, but when they are illuminated with light resistance drops dramatically.Fig 2.5Fig(2.5) is an example of a light sensor circuit :When the light level is low the resistance of the LDR is high. This prevents current from flowing to the base of the transistors. Consequently the LED does not light.However, when light shines onto the LDR its resistance falls and current flows into the base of the first transistor and then the second transistor. The LED lights.The preset resistor can be turned up or down to increase or decrease resistance, in this way it can make the circuit more or less sensitive.2.2 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 1s and 0s. This output is given to RF transmitter which is CMOS compatible & hence dont require line driver like MAX232.

2.2.1 LCD connected to microcontroller The output of ADC is given to the RF transmitter as well as to the LCD. This is done so that the user could know the ADC readings of both LDRs during the trials. Also, we have displayed which device has been toggled at the receiver end merely for the sake of convenience. The user can disconnect LCD whenever he wants to.

2.3 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 economical to use wires if the switchboard is nearby. But wires may become inconvenient for the user in most cases.

Chapter 3BLOCK DIAGRAM OF RECEIVER SECTION

Fig. 3.1 Block Diagram of Receiver Section3.1 RF Receiver This RF receiver will receive the RF signal at frequency 2.4 GHz from the RF transmitter. It will then convert the received signal into its equivalent digital form as it was at the input of RF transmitter. This digitally converted data is fed to the decision making section that is microcontroller PIC16F877A.

3.2 Decision Making Section The decision making block processes on the data available to it from the RF receiver. The microcontroller PIC16F877Ais 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.

3.3 Output Section The output section consists of the relay driver that drives the relays at its output. Since we have used only two devices to show the final output of our system, we require only two relay search for one device. 3.4 Requirements of data transmission and reception The following are the main requirements of data transmission and reception:- The transmission and reception should be essentially error free. Any disturbance of the same frequency must not hinder. It should have high distance range. Multiple samples of the eye per second should be sent. Size of the transmitter circuit should be so small that it can be implemented in spectacles itself. The RF module, we have used, operates at Radio Frequency. The corresponding frequency range varies between 30 kHz & 300 GHz. In this RF system, the digital data is represented as variations in the frequency of carrier wave. This kind of modulation is known as Frequency Shift Keying (FSK). This RF transmitter operates at a frequency of about 2.4GHz. It receives serial data in digital form from the output of microcontroller. It will convert this digital data into corresponding radio wave of the said frequency. The transmission occurs at the rate of around 250 kbps.

Chapter 4SOFTWARE DESIGN Software Used for Programming PIC16F877A. For programming our microcontroller PIC16F877A, we have used software known as MPLAB IDE v8.56.4.1 Software Description MPLAB Integrated Development Environment (IDE) is a free, integrated toolset for the development of embedded applications employing Microchip's PIC and dsPIC microcontrollers. MPLAB IDE runs as a 32-bit application on MS Windows, is easy to use and includes a host of free software components for fast application development and super-charged debugging. MPLAB IDE also serves as a single, unified graphical user interface for additional Microchip and third party software and hardware development tools. MPLAB IDE has the same user interface for all tools. MPLAB IDE has highly optimized compilers for the PIC18 series microcontrollers, high performance PIC24 MCUs, dsPIC digital signal controllers and PIC32MX MCUs and not for PIC16 series. So, for compiling the code for PIC16 series we require third party compiler. 4.1.1CompilerThe third party compiler we have used for PIC16F887A microcontroller is Hi-tech C Compiler for PIC10/12/16 MCUs. 4.2 PIC16F877AThis powerful (200 nanosecond instruction execution) yet easy-to-program (only 35 single word instructions) CMOS FLASH-based 8-bit microcontroller packs Microchip's powerful PIC architecture into an 40- or 44-pin package and is upwards compatible with the PIC16C5X, PIC12CXXX and PIC16C7X devices. The PIC16F877A features 256 bytes of EEPROM data memory, self programming, an ICD, 2 Comparators, 8 channels of 10-bit Analog-to-Digital (A/D) converter, 2 capture/compare/PWM functions, the synchronous serial port can be configured as either 3-wire Serial Peripheral Interface (SPI) or the 2-wire Inter-Integrated Circuit (IC) bus and a Universal Asynchronous Receiver Transmitter (USART). All of these features make it ideal for more advanced level A/D applications in automotive, industrial, appliances and consumer applications.4.2.1 Features of PIC16F877A 2 PWM 10-bit 256 Bytes EEPROM data memory ICD 25mA sink/source per I/O Self-Programming Parallel Slave Port

Parameter NameValue

Program Memory TypeFlash

Program Memory (KB)14

CPU Speed (MIPS)5

RAM Bytes368

Data EEPROM (bytes)256

Digital Communication Peripherals1-A/E/USART, 1-MSSP(SPI/I2C)

Capture/Compare/PWM Peripherals2 CCP

Timers2 x 8-bit, 1 x 16-bit

ADC8 ch, 10-bit

Comparators2

Temperature Range (C)-40 to 125

Operating Voltage Range (V)2 to 5.5

Pin Count40

Table 4.1:Parameter and value of PIC16F877A

4.3 MPLAB IDEMPLAB Integrated Development Environment (IDE) is a comprehensive editor, project manager and design desktop for application development of embedded designs using Microchip PICmicro and dsPIC microcontrollers4.3.1 FEATURES OF MPLAB IDE MPLAB IDE is a Windows OS based Integrated Development Environment for the PICmicro MCU families and the dsPIC Digital Signal Controllers. The MPLAB IDE provides the ability to: Create and edit source code using the built-in editor. Assemble, compile and link source code. Debug the executable logic by watching program flow with the built-in simulator or in real time with in-circuit emulators or in-circuit debuggers. Make timing measurements with the simulator or emulator. View variables in Watch windows.

4.4 PIC18 high end core devices (16 bit)Microchip introduced the PIC18 architecture in 2000.Unlike the 17 series, it has proven to be very popular, with a large number of device variants presently in manufacture. In contrast to earlier devices, which were more often than not programmed in assembly, C has become the predominant development language.The 18 series inherits most of the features and instructions of the 17 series, while adding a number of important new features: call stack is 21 bits wide and much deeper (31 levels deep) the call stack may be read and written (TOSU:TOSH:TOSL registers) conditional branch instructions indexed addressing mode (PLUSW) extending the FSR registers to 12 bits, allowing them to linearly address the entire data address space the addition of another FSR register (bringing the number up to 3)

4.5 Flowchart of System Programming

Chapter 5TEST UP AND RESULT Here we have used red LED to represent the reflected light that will come from eye & will be incident on the LDRs. This is done merely for the sake of demonstration. The actual working & result of system is shown through photographic presentation from Fig. 5.1 to Fig. 5.6

Fig.5.1 : Whole Circuit after turning ON Fig. 5.2 Receiver LCD showing Device1 & Device2 initially in OFF state

Fig. 5.3 :LED focus on LDR1 & Receiver LCD showing Device1 in ON state

Fig. 5.4 :LED refocused on LDR1 & Receiver LCD showing Device1 in OFF state

Fig.5.5 :LED focused on LDR2 & Receiver LCD showing Device2 in ON state

Fig. 5.6 :LED refocused on LDR2 & Receiver LCD showing Device2 in OFF state

Chapter 6CONCLUSION AND FUTURE SCOPE6.1 ConclusionThe cost of the system is very less. So, even middle class people can use it. This system is designed in such a manner that the disabled persons can on or off appliances without any dependence on others. The system will become complex as the appliances increases. Programming the microcontroller is another aspect, whereby the overall performance is supporting. Eye movement technology with the contribution of eye tracking facilitates the proposed system to a useful one. The system functionality is initialized from the eye sensing mechanism and thus it can be equipped in a spectacle. The sensors are fixed in the spectacle. In this world of technology and science, where emptiness is replaced by fullness, it is inevitable to know and discover more and more. As an engineering student, this is a small contribution from my part to aware you about one of the important technology, Eye Movement Technology. From the early times itself it seems that, the technology had find its own way to promote the disabled persons, this endeavour promises it.

6.2 Future scopeThis system can further be made more accurate, work in real world by making following optimizations. 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).

REFERENCES 1. International Journal Of Electronics And Communication Engineering & Technology (IJECET), Volume 3, Issue 3, October- December (2012), www.iaeme.com/ijecet.asp2. PethaniKishan V., GorMehul K. and Raja Jimit S. (2011), Intermediate Progress Report on ELECTRONIC SPECTACLES FOR PARALYZED PATIENTS Submitted in the partial fulfilment of ALL INDIA YOUNG ENGINEERS HUMANITARIAN CHALLENGE 2011 3. Tim Wilmshurst (2009), Designing Embedded Systems with PIC Microcontrollers, Second Edition: Principles and Applications, Newnes Publications 4. Paul Horowitz, Winfield Hill, The Art of Electronics - 2nd Edition, Cambridge University Press.

188

Dept. of ECE,KMCT CE19