22-06-2012, 04:43 PM
5D FOR BLINDS
5d for blind 2 appli Traffic and Anticollision.doc (Size: 465 KB / Downloads: 40)
INTRODUCTION
This project helps the blind people to walk towards their destiny, they desired, without any obstacles. Usually Blind people walk on the path, which is accustomed for them, to avoid any physical damages or injuries done by obstacles coming on the way. So this Blind Aid helps such people to choose any new road and reach their destiny without any tension.
Until well into the twentieth century, most of devices developed for measuring distance/movements worked on the same principle; comparison of the measured distance with the standard unit of length. Other advanced means are available now. One of these is the measurement of time taken by an electromagnetic / sound wave to cover a certain distance. This sound normally lies beyond human hearing and known as Ultra-sonic waves.
The novel Ultrasonic Movement Detector presented here is suitable for detecting any moving objects within the range between 25 cm and about 6 meters. The detected action in intimated by alarm sound. Hence this feature is used to help the Blind people to reach their destiny in safe way.
It is built around a matched pair of ceramic transducers, which convert movement energy to electrical energy and vice versa. The operating frequency of the pair is 40kHz. Any movement in the area scanned by the pair of transducers will be detected and a 6V pulse produced. In this Ultrasonic Movement Detector system the pulse turns on a LED. Pads are provided to take this pulse to add on circuits where it may be used to switch between an automatic reset after the detector has been triggered or to stay triggered. The unit will work reliably upto three meters after calibration.
METHODOLOGY:
The basic principle used in this device is the property of ultrasonic and waves of getting reflected when medium density charges. The ultrasonic and sound waves having a frequency range from 40 kHz are generated by an Astable Multivibrator, having 50% duty cycle. The waves generated are amplified and transmitted through a transmitting Transducer with the help of a driver stage.
The waves travel ahead and are reflected back when they strike a moving object. The receiving transducer selects the reflected waves and further they are processed in receiver section. The receiver section consists of pre amplifier, buffer, driver and a buzzer, which gives the final output. The buffer is included to provide unit gain amplification to the received waves and passes them to Driver. The output is thus amplified to drive the output stage. The output stage is a buzzer. LED is also included in the output stage for the convenience.
WORKING:
In the present scenario if we consider the handicap people face lots of simple problems in there daily life. So with respect to that we have designed this project which consists of different stages which are listed below:
1. Traffic signal monitoring system
2. Obstacle detection with variable vibration drive.
Further this project can be enhanced for other applications also..
In case of traffic signal monitoring system the blind person faces the problem that which path of the circle in traffic area is free to go ahead so in order to over come this the transmitters which are placed in the traffic signals will starts transmitting the signals which ever is green. Then the receiver module or sensor will start receiving the signal from the respective direction and he or she will come to know that which part of the traffic area is clear with the help of voice announcement so that they can take an easy move.
The fourth stage is detecting the obstacle, but it not only detects the obstacle in front of that it also informs the person regarding that with the help of vibrations. If the obstacle is at far distance then the intensity of vibration will be less and as the obstacle moves forward then the intensity will become more and more.
In this way we have implement the gadget which will help the dedicated people to lead there life safe.
CIRCUIT DIAGRAM & ITS DESCRIPTION
The Obstacle Detection System is having circuit blocks as follows: IR Trans-receiver Module, Variable Power Supply and finally Power Supply.
IR TRANS-RECEIVER MODULE
These IR Transmitter and two IR Receivers are fitted on front side of vibrator and are continuously switched ON for obstacle detection purpose.
IR TRANSMITTER
The circuit components are explained as:
IR LED: The IR LED or Infra Red Light Emitting Diode is an electronic device which gives off or emits light when current is passed through it. Like general diode, this IR LED passes current only in one direction and requires forward operation voltage of about 2V and forward operation current in 10 to 20 mA range. Maximum reverse voltage that the IR LED can withstand is typically 3 to 5V, more than this could damage the component. It does not have any current control function, so, when the IR LED is used in a circuit, a resistor must be used in series to limit the current flow through it. If greater range is required, this resistor may be reduced to a minimum value with a consequent adverse effect on current consumption. Do not reduce the value of resistor unless you do require the greater range, otherwise the relay may not trip reliably close in due to reflections caused by the high light output. For a good range, the current through the LEDs must be large. Since, however, currents, the pulses must be short, and this is why PDM is used (In this type of modulation, the time of occurrence of the first and last transition edge, is varied from its unmodulated position).