VOICE BASED GUIDANCE STICK AND ROUTER FOR THE VISUALLY IMPAIRED PEOPLE WITH MODERN GPS

TECHNOLOGY.R.ARCHANA

Abstract An embedded system is a special purpose computer system designed to perform a dedicated function. Using embedded system we are developing a voice based guidance stick and router for the blind with GPS. The IR sensor and Ultrasonic sensor are used to detect the obstacles and collision warning system. The signals from the sensor are directly given to the microcontroller which is pre-programmed to monitor the data continuously from the sensor and GPS. The places are pre-programmed in the GPS modem using MPLAB software. The voices are recorded manually which indicates the obstacle, turning points, source and destination place. When the obstacle and pre-programmed places are detected the voice chip delivers the voice information through the earphone to the visually impaired people. The keypad is used to choose the places and to guide the person through voice information. This system is designed in a way to help the visually impaired people to protecting them from the obstacles and to guide them in a safe manner. Keywords: GPS modem, embedded system, Voice chip, Ultrasonic and IR sensors.

Introduction Blind person’s lives and activities are greatly restricted by loss of eyesight, and can only walk in fixed paths that are necessary to their lives. Even if all our senses are fully functional and we are able to concentrate to the navigation purpose, it is difficult to solve all challenges in unknown areas without the help of tools. The blind long-cane remains the most widely used travel aid among the visually impaired people, whose number is 45 million and it is increasing by 7 million each year according to a World Health Organization(WHO)report[1].The blind navigation systems are divided into indoor and outdoor navigation system. In the indoor navigation system obstacle avoidance and virtual reality technology are used. In this, machine learning techniques to the task of inferring aspects of the user’s state given a stream of inputs from sensors worn by the person. Integrating the information from the diverse set of cheap, wearable sensors. The task of interactively guiding the user to a desired indoor destination. In outdoor

navigation technologies the techniques include Geographic Information System (GIS), Global Positioning System (GPS), radar, ultrasonic, speech and RFID. An integrated GPS and GIS navigation system are proposed for positioning and tracking. The RFID grid to be localized in small business, large corporate parks, government buildings or college campuses. Infrared (IR) sensors are extensively used for measuring distances. They can be used in robotics for obstacle avoidance. They have non-linear characteristics and they depend on the reflectance properties of the object surfaces. IR sensors using reflected light density to estimate the distance from an object. Ultrasonic sensors are useful for measuring distances. It is useful under conditions of poor lighting and transparent objects.

The area covered is in front of the user and just beyond the reach of the white cane, such that the system can alert the user to looming obstacles before his white cane will touch – or miss – them. To this purpose the user is equipped with a stereo

camera attached at chest height, a portable computer, and only one earphone such that normal ambient sounds are not blocked [3]. The cost of detecting path borders and the vanishing point, such that blind persons can be instructed to correct their heading direction on paths and in corridors.Description This Project deals with providing voice based help for the blind people which consists of a walking stick with an embedded controller. Here, US sensor can play an important role in determining the surface properties. The co-operation between the US and IR sensors are utilized to create a complementary system that is able to give reliable distance measurement. The walking stick consists of a controller with an IR and Ultrasonic sensor which will be interfaced with the microcontroller and will continuously monitor the distance between the blind person and any obstacle which his/her is facing while walking. The controller is programmed to continuously monitor the data continuously from the sensor and provide an appropriate indication to the user. The blind person can hear the output from the speaker which is connected to the controller. And 1*5 keypad also using to get routing from voice chip.

A location and tracking system becomes very important to our future world of pervasive computing, where information is all around us. Location is one of the most needed information for emerging and future applications. Since the public use of GPS satellite is allowed, several state-of-the-art devices become part of our life, e.g. a car navigator and a mobile phone with a built-in GPS receiver. However, location information for indoor environments is still very limited. Several

techniques are proposed to get location information in buildings such as using a radio signal triangulation, a radio signal (beacon) emitter, or signal fingerprinting. Using GPS system is a new way of giving location information to users. The GPS values stores location information and gives it to any GPS madam that is within a proximity range which can be up to 10-15 meters for GPS systems. We propose an GPS-based system for navigation in a building for blind people or visually impaired. The system relies on the location information on the tag, a userpsilas destination, and a routing server where the shortest route from the userpsilas current location to the destination. The navigation device communicates with the routing server using GPRS networks. We build a prototype based on our design and show some results. We found that there are some delay problems in the devices which are the communication delay due to the cold start cycle of a GPRS modem and the voice delay due to the file transfer delay from a MMC module. We included a motor and its output in the vibration form. The person have to switch on the motor in the traffic places because in traffic area the person not able to hear the voice information.

Components

1. GPS The GPS antenna receives the information from the satellite in the frequency range 1575.42Mhz.The signals are received and send to the microcontroller through the serial port for communication purpose. Serial port transmits the information to the microcontroller. If that person wants

to go particular place means He/She have to press the key in keypad. The controller receives and transmits this information to the GPS and it guides the person by giving voice information to the person for that particular place. It tells take turns left/right and obstacle information. It is most helpful for the person to go for a particular place with correct information.

2. Voice Chip Interface We are using APR 9600, high quality voice recording and playback solution. The voice playback capability in the range of 40-60 seconds. It is user friendly and has 8 voice outputs in chip. In our project we are using two voice chip interface. The voice is recorded manually and the recorded voice will be played when the information is obtained from the microcontroller. The voices are obstacle is in front, left side obstacle, right side obstacle, turn left, and turn right, BME Dept., Library, and Canteen and so on.

PCPA is basic personal tool for physically challenged people. The system can be used in any organizational infrastructure with proper signal conditions and Wi-Fi deployment planning for better resolutions to have directional vector information for the user and later helps a person to navigate within the organization. It assists a person to reach to specific location, within a building [4].

Web-based maps support virtual and live discovery of cities, provide spatial information and improve orientation. To properly access and view digital maps is often challenging for this user group. Therefore, a methodology based on geographic information technologies is developed to automatically generate a textual spatial description of the map (map in words) and a user specified interface

respecting the requirements of users with visual impairment [7].

3. Ultrasonic Sensor Ultrasonic (US) sensors are widely used to measure distances. Thus they have provided a reliable source of obstacle detections. Since they are not vision-based, they are useful under conditions of poor lighting and transparent objects. However, US sensors have limitations due to their wide beam-width, sensitivity to specular surfaces, and the inability to discern objects within 0.5 m. Because of the typical specular nature of the US wave’s reflection, only reflecting objects that are almost normal to the sensor acoustic axis may be accurately detected. The US sensors described in have precision of less than 1 cm in distance measurements of up to 6m. However, the time of flight (ToF) measurement is the most accurate method among the measurements used. This ToF is the time elapsed between the emission and subsequent collection of a US pulse train traveling at the speed of sound, which is approximately 340 m/s, after reflection from an object. For single measurement, this causes large response time, for example, 35 ms for objects placed 6m away().This ultrasonic sensor operates with a piezoelectric transducer as the sound emitter and receiver as the sensor consists of a transmitter and receiver that are mounted in the same housing, where the object acts as a sound reflector. The principle by which ultrasonic sensors yield measurements is that of evaluating the time taken for the sound to travel between transmission and reception. The integrated controller computes the distance from the echo time and the velocity of sound. The transmitted pulse duration Δt and the decay time of the sonic transducer result in an unusable area in which the ultrasonic sensor cannot detect an object, which is about 145ms for this sensor. The ultrasonic frequency that this sensor uses is 40 kHz.

The time of travel of the sound pulse is the means of measuring the distance of the object. The ultrasonic beam has an opening angle of around 5°. The sound pressure level outside of this cone is less than half (-6 dB) that of the value on the sensor axis. The sensing range of this sensor unit extends from 0.2 to 4 m at an ambient temperature of +20 C° and a relative air humidity of 50% [1]. The sensing range depends on the reflectance of the object such as the surface properties and the angle of incidence. Within limits, these influences can be compensated by adjusting the sensitivity.

4. Infrared Sensor Infrared (IR) sensors are extensively used for measuring distances. Therefore, they can be used in robotics for obstacle avoidance. They are cheaper in cost and faster in response time than ultrasonic (US) sensors. However, they have non-linear characteristics and they depend on the reflectance properties of the object surfaces. So knowledge of the surface properties must be known prior. In other words, the nature in which a surface scatters, reflects, and absorbs infrared energy is needed to interpret the sensor output as distance measure. IR sensors using reflected light intensity to estimate the distance from an object [6]. Their inherently fast response is attractive for enhancing the real-time response of a mobile robot .Some IR sensors described in the bibliography are based on the measurement of the phase shift, and offer

medium resolution from 5 cm to 10 m, but these are very expensive.

5. Keypad 1*5 keypad is used to choose the destination for the visually impaired person. If he/she presses any key means it will give voice output as place name. If they press correctly means it will start guiding from source to destination place by giving voice information. On the way if any obstacles are presents it will give voice output. It will inform that turn left, turn right through the microcontroller. The route and turnings are pre programmed in the controller. Thus it so helpful for guiding them correctly and reach the place safely. In [5] they used 6 keys and each key has special function, the person has to press the 6th key for finding route to the destination.6. Microcontroller The PIC 16F877A is an 8-bit microcontroller, which has an on-chip eight channel 10–bit Analog-to-Digital Converter (ADC). Samples are temporarily stored in buffers in memory. After completion of signal acquisition, the microcontroller then communicates with the GPS transceiver module on it MAX232 port to send the samples(s) continuously.

Flow Chart

Yes

No

Yes

No yes No

Yes Yes

No

No

Yes

Start

Reached Library

Initialize GPS, Voice, Ultrasonic

Voice: Left side Obstacle

A

A

A

Stop

A

A

A

A

Reached BME Dept.

If BME Dept.

If Library

If Keypad

Obstacle in Front

If Ultrasonic

If canteen

Reached Canteen

Voice: Right side Obstacle

GPS

IRR

IRL

A

Get input GPS, Ultrasonic, IRL, IRR, Keypad

No Yes

Yes

Block Diagram

ConclusionAn ultrasonic ranging system,

which is cost effective and easy-to-use, for integration into the visually impaired long-cane was developed and tested. The developed system can effectively detect the presence of obstacles with accuracy in the centimeter range. The system hardware is composed of an ultrasonic

sensor, keypad that interfaces to a microcontroller and a GPS transceiver. While the application software runs on the user’s GPS and utilizes Text-to-Speech capabilities to announce the distance and collision alerts. We have chosen the GPS implementation because GPS have been widely accepted by the visually

impaired community because of its increased performance.

References

[1]A.A.Tahat“A Wireless Ranging System for the Blind Long-Cane Utilizing a Smart-Phone “School of Electrical Engineering , Princess Sumaya University for Technology, Amman, Jordan.[2]Andrew R.Golding and Neal Lesh”Indoor Navigation using a diverse set of cheap, wearable sensors”MERL, Cambridge.[3]Joao Jose, Miguel farrajota,Joao M.F. Rodrigues,J.M.hans du Buf “The Smart Vision local navigation aid for blind and visually impaired persons” University of the Algarve (FCT and ISE), Faro, Portugal.[4]Kiran kumara Patil, Pramod, Shrihari,Vijay Kumar B.P.,T.T.Nagabhushan”A generic Information Service framework for

Physically Challenged People in Wireless Networks “International Journal of Computer and Electrical Engineering, Vol.3,no.4,August 2011.[5]Rangsipan Marukatat,Pongmanat manaspaibool,Benjawan khaiprapay, Pornpimon Plienjai” GPS Navigator for Blind Walking in a Campus ” World Academy of Science, Engineering and Technology 70 2010.[6]Tarek Mohammad “Using Ultrasonic and Infrared Sensors for Distance Measurement” World Academy of Science, Engineering and Technology 51 2009.[7]Wolfgang Wasserhurger, Jalia Neuschmid, Manfred Schrenk “Web-based City Maps for Blind and Visually Impaired “Environment and Information Society, Austria.