Passenger BUS Alert System for Blind

2013 International Conference on Circuits, Power and Computing Technologies [ICCPCT-2013]

Passenger BUS Alert System for Easy Navigation of Blind

G.Lavanya ME., Assistant Professor,

Department of Biomedical Engineering, Sri Ramakrishna Engineering College,

Coimbatore Email id:[email protected].

Abstract: Talking signs, guide cane, echolocations are all useful in navigating the visually challenged people to reach their destination, but the main objective is not reached that it fails to join them with traffic. In this project we propose a bus system using wireless sensor networks (WSNs).The blind people in the bus station is provided with a ZigBee unit which is recognized by the ZigBee in the bus and the indication is made in the bus that the blind people is present in the station. So the bus stops at the particular station. The desired bus that the blind want to take is notified to him with the help of speech recognition system HM2007. The blind gives the input about the place he has to reach using microphones and the voice recognition system recognizes it .The input is then analyzed by the microcontroller which generates the bus numbers corresponding to the location provided by the blind. These bus numbers are converted into audio output using the voice synthesizer APR 9600. The ZigBee transceiver in the bus sends the bus number to the transceiver with the blind and the bus number is announced to the blind through the headphones. The blind takes the right bus parked in front of him and when the destination is reached it is announced by means of the GPS-634R which is connected with the controller and voice synthesizer which produces the audio output. This project is also aimed at helping the elder people for independent navigation.

Keywords: Wireless sensor networks, Speech Recognition System, Voice Synthesizer, GPS, Zigbee.

I. INTRODUCTION

Out the 6.7 billion people that populate the world, 161 million are visually impaired. Each visually impaired individual faces different challenges based on their specific level of vision. With the rise of various support-based organizations, more visually impaired people have been given the opportunity to education and many other means. But still the issues of navigation for the blind are very complex and troublesome especially when they walked down in street and also navigate to distant places by public transport system. For a visually impaired person, doing things such as reading traffic signals and street signs can be extremely challenging, if not it is impossible to do.

In order to overcome these challenges, a visually impaired person might use walking cane, guide dog, and sighted guide.

978-1-4673-4922-2113/$31.00 20 13 IEEE 798

Preethy. W*, Shameem.A *, Sushmitha.R* IV year, Biomedical Engineering,

Sri Ramakrishna Engineering College, Coimbatore

shameem. [email protected]

These alternatives also called as asslstlve devices can be helpful to the blind but not so effective. The sighted guide can be immensely effective, as well provide social comfort, but it restricts the independence of the blind individual. Guide dogs and walking canes allow for a more independent means of travelling, but they are limited in unfamiliar environments. RFID is feasible and cost effective but it is more suitable for indoor communication only. Also it provides only one way communication and a very short range of identification. A system with an augmented walking cane, a pair of augmented glasses and identifiable items tagged with semacode/data matrix tags is used for outdoor navigation of blind people. If a man has to take the bus, he walks along the pavement and his walking cane recognizes a tag. But the image quality of the web camera is fairly poor. Tag recognition in darkness or in bad lightning conditions might be a problem. Another issue is that camera needs a visual, so if a tag is hidden behind a person or another object, then the camera cannot detect it. Tags on all environments will properly contaminate the environment and meet resistance from many citizens.

To overcome the drawbacks of currently available assistive devices, we propose a Wireles sensor network system with ZigBee for blind identification by the bus and embedded system for providing the bus number and [mally GPS for destination indication. Wireless sensor network (WSNs) consists of sensors that continuously monitors the environmental conditions and send their data to the main network [51. ZigBee is an embedded device for use in a WSN which is tiny in size. These nodes have processing and computational capability and generally consist of an RF transceiver, memory, on board sensors/actuators and a power source [71. ZigBee have CC2420 which is a true single-chip 2.4 GHz IEEE 802.15.4 compliant RF (Radio Frequency) transceiver designed for low-power and low-voltage wireless applications so we can send or receive useful information through using this chip. The number of the bus parked in front of the blind is send to the ZigBee in the blind system. Another function of ZigBee is identification of blind in the bus station. If both the numbers match the buzzer in the bus unit alarms and indicates the driver that there is blind in the bus station.


The software part is Embedded C with MPLAB IDE (Operating System) for programming the controller. 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.

II. MA TERIALS AND METHODS

A. Voice Recognition Unit

Speech recognition system is used to help the blind to know the particular buses for a given location. When the blind speaks through the microphone, the speech recognition system analyze the input which is then processed by the microcontroller, and then produces the required output in the audio format which is heard by the user through the headphones. The speech recognition system here we use is HM2007.It is a single chip voice recognition LSI circuit with on the chip voice analysis, recognition process and system control functions. It may consist of microphone, keyboard, RAM and some other components.

The word length select pin is used to control the length of word we are providing as input. When the pin WLEN is set high, 1.92 sec is selected. In this way only 20 words can be recognized. DEN pin is used to enable the data. When the recognition process is complete the chip will place its response on the data bus DO -D7 and which can be latched on to the microcontroller by this pin. When the device is ready for the voice input in training or recognition mode, a low signal is sent by the RDY pin. If the chip is busy then a high signal is sent. When the waiting control input pin is set Low, the chip will enter the waiting state and do not accept the voice input until the pin is set to High.

There are two modes of operation. During the power on the chip will start its initialization process. If the wait pin is Low the chip will do the memory check and if the pin is H then the chip skips the memory check. After the initialization recognition is done. Ready pin is set low to allow the voice to be recognized. Once the voice input is detected the ready pin is set high and recognition begins. We should train the word pattern before the beginning of the recognition process. After the process is completed the result will appear on the D-bus with the activation of DEN pin.

To train or clear a voice pattern, we must select the word number to process first. The number of word is composed of two digits. The digits are entered one digit at a time through keypad. When number key is pressed, the number of key will be echoed to the D-bus. When the word number is entered press the function key to choose the operation function. If the function key CLR is pressed the word pattern is cleared. If the function key TRN is pressed

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training process begins. To clear the entire patterns key 99 is entered and clear is pressed.

B. Voice Synthesizer System

APR9600 device offers true single-chip voice recording, non-volatile storage and playback capability for 40 to 60 seconds. The voice synthesizer is used to generate speech signal output of the bus number and the current destination of the blind people. The voice synthesizer is connected to the microcontroller. Microcontroller accepts input from voice recognition system and GPS. The device supports both random and sequential access of multiple messages. Each memory cell can store 256 voltage levels. This technology enables the APR9600 device to reproduce voice signals in their natural form. It eliminates the need for encoding and compression, which often introduce distortion. Storage is accomplished through a

Fig! .Functional Block Diagram of Bus Unit

P ower S upply

)I1eropbone (mpul from

u .... ) Recognition

S } l em IDI2007

(oulpul 10 us,er)

Fig2 .Functional Block Diagram of Blind Unit

Bus unit consists of a ZigBee transceiver with a microcontroller which helps to find the availability of blind in the bus station and displays it. The blind unit is a mobile unit carried by the blind people which consists of ZigBee unit for identifying the corresponding bus parked in front of them, Speech


recognition system for identifying the location provided as voice input by the user and the microcontroller for analyzing the input and providing the corresponding bus number of the location specified by the blind as audio output through voice synthesizer. Input is given through microphone and output is heard by the blind through the headset.

combination of the Sample and Hold circuit and the Analog WritelRead circuit . These circuits are clocked by either the Internal Oscillator or an external clock source. When playback is desired the previously stored recording is retrieved from memory, low pass filtered and amplified. The signal can be heard by connecting a speaker to the SP+ and SP- pins.

Random access mode supports 2, 4, or 8 messages segments of fixed duration. Record or playback can be made randomly in any of the selected messages. The length of each message segment is the total recording length available (as defined by the selected sampling rate) divided by the total number of segments enabled. The bus number and the destination which is recorded are played back in this mode.

On power up, the device is ready to record or play back, in any of the enabled message segments. To record, ICE must be set low to enable the device and IRE must be set low to enable recording. We recording b y applying a low level o n the message trigger pin that represents the message segment we intend to use. To playback, I CE must be set low to enable the device and IRE must be set high to disable recording & enable playback. You initiate playback by applying a high to low edge on the message trigger pin that representing the message segment you intend to playback. Playback will continue until the end of the message is reached. If a high to low edge occurs on the message trigger pin during playback, playback of the current message stops immediately.

The IBusy pin when low indicates to the host processor that the device is busy and that no commands can be currently accepted. When this pin is high the device is ready to accept and execute commands from the host. The IStrobe pin pulses low each time a memory segment is used. Counting pulses on this pin enables the host processor to accurately determine how much recording time has been used, and how much recording time remains. The A P R 9 6 0 0 has a total of eighty memory segments. The IM7 _END pin is used as an indicator that the device has stopped its current record or playback operation. During recording a low going pulse indicates that all memory has been used. During playback a low pulse indicates that the last message has played.

C. PIC Microcontroller

PIC is a family of Harvard architecture microcontrollers made by Microchip Technology, derived from the PIC16F887 originally developed by General

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Instrument's Microelectronics Division. The name PIC initially referred to "Peripheral Interface Controller". In our system two controllers are used. One in the bus unit and other in the blind unit. Microcontroller is connected to the level converter, speech recognition system, GPS and voice synthesizer. LCD display is connected to the output of controller in bus unit. The coding is done using embedded C language and Hi-tech C compiler. The output of the microcontroller is connected to the voice synthesizer in blind unit. The output of speech recognition system, GPS and level converter is connected to the input ports of microcontroller.

D. Finding the destination

The Global Positioning System (GPS) is a space based radio navigation system that provides reliable positioning, navigation, and timing services to civilian users on a continuous worldwide basis. GPS receiver will provide

Fig 3.Blind Unit

Fig 4.Bus Unit

location and time. It receives the latitude and longitude values from the satellite. GPS based blind man device with user input


interfacing (voice based) intellectually finds the current location and gives the alert to the blind man if it was his destination area. The system designed consists of a GPS receiver and a voice circuit which is interfaced to the microcontroller [121. The microcontroller is programmed in such a way that depending on the satellite information of location the predefined location name will be announced. Three satellites are enough to solve for position, since space has three dimensions. However a very small clock error mUltiplied by the very large speed of light the speed at which satellite signals propagate results in a large positional error. The receiver uses a fourth satellite to solve for x, y, z, and t which is used to correct the receiver's clock.

Microcontroller is the heart of the device. It stores the data of the current location which it receives from the GPS system, so that it can make use of the data stored to compare with the destination location of the user. By this it can trace out the distance from the destination and produce an alarm to alert the user in advance. This device is designed to provide a voice based announcement for the user, i.e., the user gets the voice which pronounces his destination location. GPS-634R is a highly integrated smart GPS module with a ceramic GPS patch antenna. The antenna is connected to the module via an LNA. It is capable of receiving signals from up to 65 GPS satellites and transferring them into the precise position and timing information that can be read over either UART port or RS232 serial port.

E. Transmission Unit

ZigBee is wireless technology developed by IEEE 802.15.4 - 2003 standard for low cost, low power, wireless sensor networks that is used for Low-Rate Wireless Personal Area Network (LR- WPANs). The standard takes full advantage of IEEE 802.15.4 physical radio specification that requires a low data rate, long battery life and secure networking. ZigBee is present with the blind people and in the bus which is the used instead of RFID [21. The ZigBee with the blind recognizes the bus which is few meter distance away from blind and gives intimation to the blind who is carrying it. The intimation is given through the headphones. The ZigBee in bus receives the signal from blind people and stops in bus station. If the blind gets the required bus, he gets into bus or else he waits for the bus which he desires to get into to reach his destination. The advantage over of ZigBee over RFID is that it is less cost than RFID tag and RFID reader [31. Secondly, it has two-way communication that is to send and receive signal at higher speed without interfering other signals like radio waves.

III. RESULTS AND DISCUSSION

When the person reaches the bus station, he can find the buses that pass through a particular location with the help of voice recognition system and voice synthesizer.

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When the bus approaches the bus station, there is an indication in the bus by the beep sound of a buzzer that there is a blind person available in the bus station. This is achieved with the help of ZigBee unit both in the bus unit and blind unit. Finally when the bus reaches the station the bus number is announced to the blind through headphones.

There are currently available systems for the outdoor navigation but they will not assist in travelling to unfamiliar areas. Some systems use PDA which is not so economic and cannot be afforded by all. In most of the systems RFID tags are used which are required in 1000s of numbers for tracking of route. Also it provides only one way communication. The system we use is a mobile unit, weightless and economically feasible.

IV. CONCLUSION

Primarily, the blind person in the bus station is identified with RF communication. The blind informs the location he needs through the microphone which is given to the voice recognition system which produces the output of bus numbers in the voice synthesizer unit which is heard in headset. Then this location is transmitted to the transceiver in the bus. If the names in the transceiver in the bus matches with that of the name send by the blind, then there is an alarm in the bus unit alerting the presence of blind and a voice to the user's headset that the particular bus has arrived. With the help of GPS tracker connected with audio output the destination chosen by the blind is intimated when the bus reaches the correct location. PDA's can be used for GPS tracking but it is not cost effective.

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Passenger BUS Alert System for Blind

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