Report on Instrumentation and Management - Assignment Example

Design Report Accelerometer based smart wheelchair Instrumentation and Measurement ENM2104 Engineering Design Process Confidentiality Notice Access to this document and referenced documents is provided to the recipient under the following conditions: 1) The contents are to be used solely for the purposes of the ENM2104 Unit at The School of Engineering, Edith Cowan University 2) The document will not be made accessible to any external party other than (if necessary) lecturers currently engaged by ECU under a contract which addresses confidentiality 3) Any requirement to vary these conditions is to be referred to the ENM2104 Unit Coordinator © Edith Cowan University 2016 Except as provided by the Copyright Act 1968, no part of this document may be reproduced, stored in a retrieval system or transmitted in any form or by any means without the prior written permission of the Edith Cowan University. Enquiries should be directed to the ENM2104 Unit Coordinator. Executive Summary The proposed model is a wheelchair prototype built around eight bit microcontroller platforms. The microcontroller takes the input from various sensors installed on the chair covering all the directions and provides corresponding outputs that helps users to take decision for the safe movement and control of the chair. An analogue joystick is installed for movement control. The output of the joystick is analogue therefore there is a need for an analogue to digital converter to produce the microcontroller input for processing. A 20x4 line LCD module is interfaced through microcontroller to display necessary information for the user. A speed control is also provided through an accelerator. It also has a low power microcontroller based LED headlights for night vision and indicator bulb for safe drive Scope The wheelchair is one of the commonly used devices used in order to enhance personal mobility of people with disabilities. It is approximated that about 1% of the population of the world need wheelchair. With respect to that, it is important to have well-designed and fitted wheel chairs in order to enhance not only mobility but also open up a world of work, education and better social life for all who need such support. Our approach allows the users to use gestures of movement such as hands and in return this is synchronized with wheelchair movement in order to improve the comfort of the users. Design Summary The microcontroller is the center of everything it receives inputs from the accelerometer analogue joystick keypad and ultrasonic sensor process the information and relays it to the LCD display or GSM module or motor control module in accordance to the results from the microcontroller. TABLE OF CONTENTS 1.Introduction 6 2.Implementation 6 Sensor Selection 7 3.Measurement System Implementation 9 4.Conclusion 10 1. Introduction There has always been a tremendous need for an affordable and well-designed electric power wheelchair to the needy. The importance of electric powered wheelchair which provides the driving force by the help of electric motor on both wheels has been of great concern in the recent past. Block diagram of ultrasonic sensor with accelerometer smart wheelchair Accelerometer, analogue joystick, ADC, keypad, ultrasonic sensor, GSM Module and motor module. In accelerometer and ultrasonic sensor gives input to the ADC and ADC converter analogue input into digital output is transmitted to the controller and then transmitted by GSM module to mobile receiver. DC motor which are interfaced to the controller by the motor driver controls the direction of the wheelchair 1.1. Description of the Project This project design provides a ultrasonic sensor with accelerometer based smart wheel chair using a microcontroller. The above integration helps the disabled persons to find their way from place to place as the venture into day to day activities. The advantage of having an accelerometer based smart wheel chair is that it can detect an obstacle and the wheels steer themselves away from the obstacle thus making them suitable for even blind persons 2. Implementation The ultrasonic sensor with accelerometer based smart wheel chair using microcontroller is designed using aAT89S52 Microcontroller for monitoring requirements. The effectiveness of the control systems proposed was verified by use of driving experiments on the practical plain road. Accelerometer and ultrasonic sensor both work as monitoring devices and they work concurrently .the ultrasonic sensor detects if there is any presence of an obstacle while the accelerometer tilts the wheels with respect to the presence of obstacle or not. If we have an obstacle the wheels tilts and the opposite is also valid. The information from the accelerometer and the ultrasonic sensor are then fed to the microcontroller which interfaces this information to GSM modem and LCD display which are in turn fed to mobile phone and motor control analoguejoystick respectively . Microcontroller based LED headlights, taillights provide night vision. The wheelchair is outfitted with a highly responsive real-time accident information system. The system will send alert signal to the concerned persons through sms or call in case of an accident. The system will accept analogue input from a 3-axis accelerometer; ADC will convert it into digital signal; microcontroller will process this digital signal to make decisions and finally the output values will be used to send alert through GSM modem accordingly. The ultrasonic sensor will send signal to the microcontroller and according to the signal microcontroller can turn the wheel chair left or right with the help of dc motor. 2.1. Abstracting the Problem Based on the requirement of the wheel chair to be designed, the main objective this project is to design a low cost prototype of a self-driven, power assisted smart wheelchair for the disabled belonging to poor community. The wheelchair is equipped with all the necessary electronics to ensure safety and ease of operation. It will be made user friendly to reduce the load of caretakers and will boost the confidence level of the disabled persons by making them self-dependent. The wheelchair is designed for persons who cannot walk due to one reason or another. The system is divided into two main units which are:- 1. Mems sensor 2. Wheelchair control. The mems sensor is connected to the hand on wheelchair. This sensor is of a 3-axis accelerometer and ultrasonic sensor converts into digital values and gives it to the 8051 controller. 2.2. Division of Tasks Accelerometer and ultrasonic sensor work hand in hand. The accelerometer used here has 3 axis. It measures the physical acceleration experienced by an object due to inertial force or due to mechanical excitation. This sensor is composed of a poly-silicon surface-micro machine sensor with a signal conditioning circuit that implements an open loop acceleration measurement architecture with an analogue output. On the other hand the ADL335 employs single structure in sensing the axes X, Y, and Z. Thus, the axes sense directions in an orthogonal with a cross-axis sensitivity. 2.3. Problems Faced Since the output of the accelerometer and the analogue joystick are analogue is nature there is a need for an analogue to digital converter which is a 0808 type in this case. After the conversion the output if fed to the AT8952 microcontroller. This prototype requires a battery bank therefore can’t work in absence of power which might leave a disabled person stranded on his or her way. The wheel chair might be expensive to some patients since in most cases disabled persons are majorly poor. Sensor Selection 2.4. Identification of the Sensor Type Ultrasonic sensors is appropriate because it uses an electrical-mechanical transformation of energy to measure distance of the target object in relation to position of the sensor. Since, ultrasonic waves travel in a longitudinal mechanical ways that follows a series of compressions followed by rarefactions along the path of wave transmission through the media. In addition, ultrasonic sensors are applied in a number of fields such as material testing, object detection, position detection, ultrasonic mouse, etc. 2.5. Performance Test of the Sensor Based on the working behaviour of these type of sensors, they are classified into two, piezoelectric sensors and electrostatic sensors. For instance, the piezoelectric ultrasonic sensors employs the piezoelectric materials in generating the ultrasonic waves. fig-2 ultrasonic sensor with Wheelchair An ultrasonic sensors is made up of transmitters and receivers which can be available as separate units or embedded into a single unit. Fig -3 circuit diagram of ultrasonic sensor with Microcontroller 3. Measurement System Implementation 3.1. Hardware Configuration 1. Microcontroller This is low power driven CMOS 8-bit configured based on the AVR RISC architecture. ATmega8 to achieve inputs that approaches 1 MIPS/ MHZ. This allows the system designer to optimise power consumption versus processing speed. 2. Tilt sensor Acceleration is avector force which has direction and magnitude and is measured in meters per second. By monitoring the three axis acceleration one can measure the level of tilt of any platform on which the device is mounted. 3. Motor and motor drive. Motor receives power from its motor drive IC .this power is utilized to do physical work, for example move the wheel chair. DC motor orientation, speed and operation can be controlled with microcontroller. Here, the motro can be started, stopped or made go either directions and its speed is controlled by the help of pulse width modulation, (PWM). 3.2. Software Configuration The programming of designed systems is done with the help of high level language such as embedded C. For example, the AVR studio 4, is used in writing programs for any AVR series of microcontrollers based on RISC architecture on windows platform. After writing the program we have to compile it with the help of AVR gcc compiler and AVR gdb debugger and if there is no error it converts high level language to machine level language in the form of ones and zeros and generates a hex file with extension hex this hex file is used to burn inside the microcontroller flash memory with the help of a programmer the program memory has limited life time for AVR microcontroller family it may be programmed up to 10 thousand times. Fig. Flow chart Test Accuracy and speed are the essential features of an effective GSR system. In addition, to meet two features, GSR systems is faced with challenges such as large variance that exists among individual hand patterns such as tracking, variation and motion. Thus, in order to get a successful GR system, high degree of flexibility is needed so that the variances can be accommodated. The GRS process follows the following steps: 1. Capturing of hand gesture by use of an accelerometer sensor is done and then converted from analogue-to-digital. 2. All the other gestures get converted to signal features that the microcontroller can use to operate. 3. The different gestures detected is then compared to already existing information. As a result, the output is displayed on the LCD screen in the 3 Coordinates(X, Y, and Z). This LCD is used to shows the numerical values that relates to the position of hand. 4. In cases of serial transmission, an encoder is employed where an RF transmitting antennae is used at a 433MHZ frequency. 5. On the side of the receiver, H bridge is required that has four switches. This switches operates in such a manner that switches S1 and S4 as per first figure are closed, S2 and S3 will be open and a result causing positive voltage across the motor. On the other hand, when S1 and S4 are open while S2 and S3 are closed, a reverse voltage is experienced across the motor thus making the motor to operate in a reverse mode. RESULTS AND DISCUSSION S1 S2 S3 S4 Result(direction of motor motion) 1 0 0 1 Right 0 1 1 0 Left 0 0 0 0 Stop 0 1 0 1 forward 1 0 1 0 Back Table 2 Binary Switching Conditions By use of the above procedure, the input part that interfaces with the gesture recognition module and the accelerometer to the CMOS 089C52 controller is made as shown in the previous figure 3. Based on this, the working model was made to aid the movement of the wheelchair. This was possible due to the use of two DC motors, 89C52 microcontroller and other necessary equipment which resulted into the proper movement of the Wheelchair in all the directions. 4. Conclusion This project is based on fiction safety driving control scheme for electric power assisted smart wheelchairs that can be control by keypad interfacing with microcontroller which is based on electric power monitoring management system based upon a wireless sensor network. This system employs the AT89S52 as MCU for real-time satisfaction, compatible and reliable monitoring requirements. The bulky and complex designs have, however, been overcome by exploring new smart wheelchairs. Interfacing these special sensors was controlled by the AT89S52. The sensors types can be improved to play a secondary role in sharing the control of the wheelchair. The developed system can measure multiple electric parameters automatically such as tilting, obstacle and battery power backup which are desired by the electric administrator References List of references [1] Srishti, Shalu, Prateeksha Jain, “The Smart Wheelchair Using Head Gesture Control”, International Journal of Advanced Engineering Science and Technological Research, vol.3, Issue 1 March 2015,ISSI 2321-1202. [2] JavajjiVeeraiah., P.V.N AravindSyam,.N.NagaDurga., K.RaviKanth., G.Vasudha, “Accelerometer Based Gesture Recognisation for Wheel Chair Direction Control Using ZIGBEE Protocol”, International Journal of Technological Exploration and Learning (IJTEL), Vol. 2, No.2, pp.104-108, April 2013. [3] ShreedeepGangopadhy., SomsubraMukherjee, Soumya Chatterjee, “Intelligent Gesture Controlled Wireless Wheelchair For The Physically Handicapped”, Proceedings of Fifth IRAJ International Conference, Pune, India,Vol.1,No.7,pp.47-52, 15 September 2013. [4] MoniruzzamanBhuiyan, Rich Picking, “A Gesture Controlled User Interface For Inclusive Design And Evaluation Study Of Its Usability”, Journal of Software Engineering and Applications,Vol.4,No.9,pp.513-521,September 2011. [5] Aleksandra Pajkanovic, BrankoDokic, “Wheelchair Control by Head Motion”, Serbian Journal of Electrical Engineering, Vol.10, No.1, pp.135-151, February 2013. [6] P. Jia, Huosheng H. Hu.,Tao Lu., Kui Yuan., “Head gesture recognition for hands-free control of an intelligent wheelchair”, An International Journal on Industrial Robot, Vol.34, No.1, pp.60-68, 2007. Read More