EYEBALL CONTROLLED WHEEL CHAIR ROBOT FOR DISABLE PEOPLE -Upcoming product for disable ABSTRACT: To operate the wheel chair of a paralyzed patient using their eyeball movement using embedded system.It is very difficult to understand the emotions of the paralyzed patients, care them and to move them according to their wish. To solve this problem this system is implemented.The system consists of the eyeball sensor, which detects the movement of the eyeball of the paralyzed patient and sends the information to the microcontroller.the microcontroller processes the signals coming from the eyeball sensor and controls the wheel accordingly. The moments of the wheelchair that can be controlled by the microcontroller are forward, right and left. When the eye moves to the left side the wheelchair moves to the left side. When the eye moves to the right side the wheelchair moves to the right side . When the eye looks straight wheelchair moves in forward direction. To control the action of the wheel chair motors are used. The motors are drive by the motor drivers. The motors are coupled with the wheels and the wheels are attached to the wheelchair mechanism. GENERAL BLOCK DIAGRAM: Eyeball Microcontroller Sensor Battery Buffer Left Side Motor Right Side Motor Driver Driver Left Motor Right Motor Left Wheel Right Wheel Wheel Chain Mechanism MICRO CONTROLLER: The difference between Microprocessor and Micro controller is “OFF” a device, you need peripheral ICs to do this work Microprocessor can only process with the data, Micro with Micro controller you can directly control the device. controller can control external device. That is if you want switch “ON” or INTRODUCTION TO ATMEL MICROCONTROLLER: SERIES: 89S51 Family, TECHNOLOGY: CMOS The major Features of 8-bit Micro controller ATMEL 89S51: 8 Bit CPU optimized for control applications Extensive Boolean processing (Single - bit Logic ) Capabilities. On - Chip Flash Program Memory On - Chip Data RAM Bi-directional and Individually Addressable I/O Lines Multiple 16-Bit Timer/Counters Full Duplex UART Multiple Source / Vector / Priority Interrupt Structure On - Chip Oscillator and Clock circuitry. On - Chip EEPROM SPI Serial Bus Interface Watch Dog Timer ANALOG TO DIGITAL CONVERTER: ADC0809 data acquisition component is a monolithic converter features a high impedance chopper CMOS device with an 8-bit analog-to-digital stabilized comparator, a 256R voltage divider converter, 8-channel multiplexer and with analog switch tree and a successive microprocessor compatible control logic. The approximation register. Fig 5.7 Pin Diagram of ADC0809 OPERATION OF THIS CIRCUIT: 10000000 is less than the correct digital representation. Wi The MSB is left at ‘1’ and the next lower significant bit is th the arrival of START command, the SAR sets the MSB made ‘1’ and further tested. However, if input is less than d1=1 with all other bits to zero so that the trial code is the DAC output, then 10000000 is greater than the correct 10000000. The output of the ADC is now compared with digital representation. analog input. If input is greater than the DAC output then +5V 22 0 - + 10 u 10 0n CQX3 5A Vc c Vref (+) 11 1 I N0 26 21 d0 A I N1 27 20 d1 N I N2 28 19 d2 A I N3 1 18 d3 L I N4 2 8 d4 O I N5 3 15 d5 G I N6 4 14 d6 I /P I N7 5 17 d7 AD C 080 9 6 STAR T 22 AL E 7 EOC 9 O/P EN 10 C LK 25 24 AD D R ESS 13 16 23 GND Vref (-) A/D converter Circuit Diagram CIRCUIT DESCRIPTION: The output from the filter is given to pin 26 of control signals from the ADC are given to port 2 of ADC 0809 shown in fig .The address channels A,B,C the microcontroller. This circuit follows the principle are grounded so that channel 1 is enabled. The of successive approximation method and when the digitized output from the converter is given to port 0 start of conversion goes high, it marks the beginning of micro controller. The filter capacitors in the circuit of the process and high end of conversion marks the remove the low and high frequency noises. The end of it. LIGHT DEPENDENT RESISTOR (LDR): LDRs or Light Dependent Resistors are very applications are display of display of numeric and useful especially in light/dark sensor circuits. Normally alphanumeric characters in dot matrix and segmental the resistance of an LDR is very high, sometimes as displays. high as 1000 000 ohms, but when they are illuminated with light resistance drops dramatically. LCDs are of two types: A photoresistor or light dependent resistor or I. Dynamic scattering type cadmium sulfide (CdS) cell is a resistor whose II. Field effect type resistance decreases with increasing incident light intensity. It can also be referred to as a photoconductor. The construction of a dynamic scattering liquid A photoresistor is made of a high resistance crystal cell. The liquid crystal material may be one of semiconductor. If light falling on the device is of high the several components, which exhibit optical properties enough frequency, photons absorbed by the of a crystal though they remain in liquid form. Liquid semiconductor give bound electrons enough energy to crystal is layered between glass sheets with transparent jump into the conduction band. The resulting free electrodes deposited on the inside faces. electron (and its hole partner) conduct electricity, When a potential is applied across the cell, charge thereby lowering resistance. carriers flowing through the liquid disrupt the molecular alignment and produce turbulence. When the liquid is LCD DISPLAY: not activated, it is transparent. When the liquid is Liquid crystal cell displays (LCDs) are used in activated the molecular turbulance causes light to be similar applications where LEDs are used. These scattered in all directions and the cell appeas to be nemayic type and actually twists the light passing bright. through the cell when the latter is not energised. This phenomenon is called dyanamic scattering. Liquid crystal cells are of two types: The construction of a field effect liquid crystal i. Transmittive type display is similar to that of the dynamic scattering ii. Reflective type type,with the exception that two thin polarizing In the transmittive type cell, both glass sheets optical filters are placed at the inside of each glass are transparent, so that light from a rear source is sheet. The liquid crystal material in the field effect scattered in the forward direction when the cell is cell is also of different type from employed in the activated. dynamic scattering cell. The material used is twisted OVER ALL CIRCUIT DIAGRAM: OPERATION: depends on your eye intensity level,how means if that LEFT MOMEMENT: person change eye ball position the display shows The the person who used that wheel chair some value.That value has been stored by using the should wear the glass, in that glass consist three LDR enter switch .Afterwards make some adjesments by and two LED.The LED transmits some light in your using min and max switch,because avoid the eyes.Normally the whight colour absorb and reflect lightening errors. the light energy,but black colour only obsorbs the Now the output of ADC and the display light energy doesn’t reflect.If that person see left side setting value both are digital values,these two inputs are means that left LDR gets less intensity compare to given to the microcontroller.The microcontroller performs other two LDRS,because the person’s eye ball in the comparision process it will compare both the values.If front of left LDR. the output of ADC coincidence with left value of diplay According to LDR working principle, setting,it produded the output.The output of I α 1/R microcontroller is given to left motor drive because left Due to less intensity in left LDR that LDR has high value is match. resistance value.In LDR transmits the analog value at left side motor,so the left wheel rotates backward high resistance only.So,that particular analog voltage direction.But the right motor rotates forward send to thADC,that covets analog to digital.Because direction.So the wheel Now the the left before that process we set some initial digital values motor drive output is given to now moves towards backward direction.But the right motor rotates left direction. forward direction.So the wheel now moves towards right direction. RIGHT MOMEMENT: FRONT MOVEMENT: The the person who used that wheel chair The person looks straight means middle LDR gets should wear the glass, in that glass consist three LDR the less intensity,because your eye ball in front of and two LED.The LED transmits some light in your middle LDR.According LDR working principle, eyes.Normally the whight colour absorb and reflect I α 1/R the light energy,but black colour only obsorbs the In that the resistance value is high because of less light energy doesn’t reflect.If that person see right intensity.So that middle LDR only transmits the analog side means that right LDR gets less intensity compare voltage to the ADC,that ADC converts analog to to other two LDRS,because the person’s eye ball in digital.Because the presetting front value is also digital front of right LDR. value.The ADC and the DISPLAY output both are According to LDR working principle, given the input of microcontroller.The microcontroller I α 1/R compares both the ADC and DISPLAY values.If front Due to less intensity in right LDR that value is match.So the supply is given to both the left LDR has high resistance value.In LDR transmits the and right motor.The left motor produces the torque,the analog value at high resistance only.So,that particular left wheel rotates.Same as the right motor produces the analog voltage send to the ADC,that covets analog to torque,the right wheel rotates.Now finally the moves digital.Because before that process we set some towards the forward direction without any other initial digital values movements. STOP: depends on your eye intensity level,how means if that The person closed the eyes means no one LDR gets person change eye ball position the display shows the reflects. So the motor drives also cannot gets the some value.That value has been stored by using the supply.So now the wheel chair is at the stop position. enter switch .Afterwards make some adjesments by using min and max switch,because avoid the FEATURES: lightening errors. The cost of this product is very less compare Now the output of ADC and the to remote controlled wheel chair. display setting value both are digital values, these Once purchase this product use life long . two inputs are given to the microcontroller. The If it useful for all kind of people because microcontroller performs the comparision process it change the presetting value is very easy. will compare both the values.If the output of ADC Improve the disable people self- coincidence with right value of diplay setting,it confidence,because they move theirself. No others help. produded the output.The output of microcontroller is Output is more accuracy compare to remote given to right motor drive because right value is controlled wheel chairs. match. Simple construction apart from wheelchair Now the the right motor drive output additionally we need one circuit board and two DC is given to right side motor,so the right wheel rotates series motors.
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