Sensor assisted stick for the blind people G.Prasanthi 1 P.Tejaswitha 2 1Professor, Dept. of Mechanical Engineering, JNTUA College of Engineering, Ananthapuramu, A. P. 2 PG Research Scholar, Product Design, Dept. of Mechanical Engineering, JNTUA College of Engineering, Ananthapuramu, A. P. Abstract: The Blindness is frequently used to describe severe visual impairments with or without residual vision. The application of ultrasonic ranging scheme for producing electronic walking stick for the blind is a technological advancement. There is a great dependency for any type of movement or walking within area or out of the particular area, they use only their natural senses such as touch or sound for identification or walking.to overcome all these problems of blind people, need to develop a project by using simple available technologies. This walking stick for blind people which have multiple sensors, with the help of sensors it has possible to enhance more features to the walking stick. The features are to detect the obstacle for collision avoidance, it detects the object in directions up, down and front. The other sensor placed near bottom tip of the walking cane to find the pits on the ground. Integrate these sensors to the voice record and play chip. Voice record in the different tracks; respond for different sensors to give the audio message to the blind person by the speaker to alert. In this project, sensors plays key role to detect the objects in all directions to make free to walk for the blind people. Keywords: Blind walking stick; Distance measuring sensor; Microcontroller; Servomotor. I. INTRODUCTION Blindness is a state of lacking the visual perception due to physiological or neurological factors. The partial blindness represents the lack of integration in the growth of the optic nerve or visual centre of the eye, and total blindness is the full absence of the visual light perception. In this work, a simple, cheap, friendly user, smart blind guidance system is designed and implemented to improve the mobility of both blind and visually impaired people in a specific area. The proposed work includes a wearable equipment consists of light weight blind stick and sensor based obstacle detection circuit is developed to help the blind person to navigate alone safely and to avoid any obstacles that may be encountered, whether fixed or mobile, to prevent any possible accident. The main component of this system is the infrared sensor which is used to scan a predetermined area around blind by emitting-reflecting waves. The reflected signals received from the barrier objects are used as inputs to ATMEGA microcontroller. The microcontroller is then used to determine the direction and distance of the objects around the blind[1]. The main objective of this project is to develop an application for blind people to detect the objects in various directions, detecting pits and manholes on the ground to make free to walk. II. MODELLING AND ASSEMBLY OF WALKING CANE Modeling is done using Pro/E creo 5.0. Software. PTC Creo formerly known as PRO/ENGINEER is a parametric, integrated 3D CAD/CAM/CAE solution created by Parametric Technology Corporation (PTC). It is the world s leading CAD/CAM /CAE software, gives a broad range of integrated solutions to cover all aspects of product design and manufacturing. It was the first to market with parametric, featurebased, associative solid modeling software. The application runs on Microsoft windows platform, and provides solid modeling, assembly modeling and drafting, finite element analysis, direct and parametric modeling and NC and tooling functionality for mechanical engineers. The modeling and assembly of sensor assisted stick is shown in Fig 2.1. Figure 1: Modeling and Assembly of walking cane 12
III. BASIC COMPONENTS The main basic components presented in this project are [2,3]: Microcontroller Sensors Power supply Servo motor Buzzer Voice record and play back device Speaker I. Microcontroller: II. III. Transactions on Engineering and Sciences The ATmega8 is a low-power CMOS 8-bit microcontroller based on the AVR RISC architecture. By executing the powerful instructions in a single clock cycle, the ATmega8 achieves throughputs approaching 1 MIPS per MHz, allowing the system designed to optimize power consumption versus processing speed. The AVR is a modified Harvard architecture machine with program and data stored in separate physical memory systems that appear in different address spaces, but having the ability to read data items from program memory using special instructions. Sensors: Distance measuring sensor unit composed of an integrated combination of (PSD) position sensitive detector, (IRED) infrared emitting diode and signal processing circuit. The variety of the reflectivity of the object, the environmental temperature and the operating duration are not influenced easily to the distance detection because of adopting the triangulation method. This device outputs the voltage corresponding to the detection distance. So this sensor can also be used as a proximity sensor. Power Supply: There are many types of power supply. Most are designed to convert high voltage AC mains electricity to a suitable low voltage supply for electronic circuits and other devices. A power supply can be broken down into a series of blocks, each of which performs a particular function. IV. Each of the blocks described below: Figure 2: Block Diagram of a Regulated Power Supply System Transformer - steps down high voltage AC mains to low voltage AC. Rectifier - converts AC to DC, but the DC output is varying. Smoothing - smoothes the DC from varying greatly to a small ripple. Regulator - eliminates ripple by setting DC output to a fixed voltage. Servo motor Figure 3: Working of Servo motor A servomotor is a rotary actuator that allows for precise control of angular position, velocity and acceleration. It consists of a suitable motor coupled to a sensor for position feedback. It also requires a relatively sophisticated controller, often a dedicated Module designed specifically for use with servomotors. Servomotors are not a specific class of motor although the term servomotor is often used to refer to a motor suitable for use in a closed-loop control system. 13
V. Buzzer The Piezo buzzer produces sound based on reverse of the piezoelectric effect. The generation of pressure variation or strain by the application of electric potential across a piezoelectric material is the underlying principle. These buzzers can be used to alert a user of an event corresponding to a switching action, counter signal or sensor input. They are also used in alarm circuits. The buzzer produces a same noisy sound irrespective of the voltage variation applied to it. It consists of piezo crystals between two conductors. When a potential is applied across these crystals, they push on one conductor and pull on the other. This, push and pull action, results in a sound wave. Most buzzers produce sound in the range 2 to 4kHz. Figure 4: Buzzer The red lead is connected to the input and the black lead to the ground. VI. Voice record and play back device: This circuit offers true single-chip voice recording, non volatile storage and Playback capability for 40 to 60 seconds. It supports both random and sequential access of multiple messages. It can be used in three different modes. The device is ideal for use in portable voice recorders. VII. Speaker: It is 8 ohms speaker and is connected to the voice recorder and it spokes out the corresponding voice when Distance measuring sensor detects the obstacle. For example if Top side sensor detects some obstacle on its side it sends the signal to the microcontroller and program is executed and it sends the signal to voice recorder control and master pin and the voice already recorded in voice recorder will speaks out through the speaker Top Top Top Top. VIII. Basic Block Diagram: Figure 5: Record and playback unit Figure 6: Basic Block Diagram 14
The two Distance measuring sensors are connected to the input a terminal of the micro-controller, the buzzer and Servo motor is connected to the output terminals. Sensor 1 joined with Servo motor. The block diagram consists of the arrangement of the components in a schematic way the block diagram is as shown in fig 2, 3, 4. IV. When power is applied to the circuit for the first time, all the sensors and motors are switched off. All sensors are configured as inputs and motor, buzzer is configured as outputs [5,6]. The servomotor starts rotating towards the upward and forward direction, since the distance sensor is mounted on the servo motor its orientation also changes. There are two sensors WORKING Sensor1 measures the obstacle between the head and front side of the travelling path Sensor2 measures the obstacle in the bottom direction for pits and floor based obstacles. The sensors are set a threshold limit if any obstacle is found within that range it gives beep and also speech through speaker. Obstacles found in different directions are indicated with different pattern beep and speech (Top, Middle, Pit and Water) to identify them easily. V. RESULTS The features presented to the Multi sensor blind stick are as follows. Figure 7: Multi Sensors Figure 8: Fabrication of Multi Sensor Blind stic A. Estimated cost: The estimated cost and the components required are shown in the table 5.1. Table 1: Estimated cost Analysis: S. No Component 1 Distance Measuring Sensors 2 Servo motor 3 Walking Stick 4 Micro controller & its 5 Miscellaneous No. Required Cost (Rupees) 1 745 1 450 3,000 Total=17,195 When these sticks are released in a large amount in the market then their cost will reduces. VI. CONCLUSION This work reports the designing of the Multi sensor blind stick. This will be useful for the visually impaired people. This blind stick consistss of advanced features which detects front and top side of the obstacles, pits and water stagnated/manholes on the ground. Due to these features it is the best equipment for blind and visually impaired people for walking on the road. It is simple, cheap, configurable, easy to handle intelligent guidance system. The system is designed, implemented, tested and verified, the results indicate that the system is efficient and unique in its capability in specifying the source and distance of the 15
REFERENCES [1] World Health Organization (WHO) media centre factsheet(2011), http://www.who.int/mediacentre/factsheets/fs282/en [2] Electronic Devices and Circuits by Jacob Millman & Christos C. Halkias [3] Linear integrated circuits by D. Roy choudary. [4] Micro processors and interfacing by Douglas V. hall [5] J. Burroughs, X-10 home automation using the PIC16F877A, Lamp, vol. 10, article 10, 2010. [6] D. Dakopoulos and N. G. Bourbakis, Wearable obstacle avoidance electronic travel aids for blind: a survey, IEEE Transactions on Systems, Man and Cybernetics C, vol. 40, no. 1, pp. 25 35, 2010. 16