Touch Screen Based Wireless Multifunctional

Wheelchair Using ARM and PIC Microcontroller

Soniya D. Makwana Prof. Anuradha G. Tandon
Department of Instrumentation and Control Department of Instrumentation and Control
Institute of Technology, Nirma University Institute of Technology, Nirma University
Ahmedabad, India Ahmedabad, India

Abstract—Smart robotic wheelchair has a great introduces another feature of emergency calling wherein
significance in life of a disabled person. With several dialing a particular number user can gain help of any care
merits, a wheelchair becomes a dilemma for a disabled taker. Thus the proposed system saves human effort, reduces
person when comes to self-propulsion. This project complexity of operation.
describes an economical solution of robot control systems.
The presented wheelchair control system can be used for II. ARCHITECTURE OF WHEELCHAIR SYSTEM
different sophisticated robotic applications. The The implementation can be categorized in two sections,
automatic robotic wheelchair comprises of the features like hardware and software. The Hardware implementation
sensing hindrances and circuitry to avoid colliding to includes interfacing dual motor driver with PIC16F887 [5],
obstacle and emergency calling. Implementing embedded GSM module, ultrasonic sensor along with RF receiver. The
systems solution on self-propelled wheelchair enhances Software implementation emphasis on programming the PIC
upgradability. This paper briefs a multifunctional microcontroller through MPLAB®X IDE, designing of GUI
wheelchair for disabled mob using, touch screen, display using KEIL µvision5 and STM32F429 libraries.
ultrasonic sensor and GSM system interfaced through
microcontroller which ultimately abolishes switching
A. Hardware Implimentation
technology and thus optimizing hardware cost.
Four motors are interfaced with controller with help of
Keywords—touch screen; PIC; wheelchair; ultrasonic sensor; motor driver. 12v battery supply is given to duel motor driver.
GSM; wireless; robotics Duel motor driver based on H Bridge controls the movement
of motor which are connected with wheelchair enable to move
I. INTRODUCTION wheel chair forward backward left and right direction.
Complete solution is presented in this paper. Body of
wheelchair is customized in such a way that touch screen
panel is placed on armrest pad and rest of the circuitry is
boxed just underneath the seat and above the cross brace,
making the arrangement lucid, steadfast thereby letting users
see just the relevant details. By enabling touch screen the user
can control the mobility of wheel chair by one finger touch.
Along with wheelchair movement it facilitates obstacle
avoidance facility and emergency calling which leads a merit
for a care taker besides just for the disabled person
him/herself.

This intelligent system comprises of RF transceiver,

GSM module, ultrasonic Hc-sr04, Touch screen and one PIC
microcontroller which gathers command and controls the
wheelchair operations accordingly. The work herein is entirely
controlled by TFT touch module stm32F429 and the
commands from the touch screen through RF transmitter are
received by the microcontroller. The command received by
PIC further decodes the signal and performs the specific
operation in accordance with the option chosen on the Touch
module. At times when critical situation arises, the user may
need to ping some another person to seek help. This work
Fig. 1 Block diagram of receiver section
 III. DESIGN AND DEVLOPMENT

A. Design Of Touch Pannel

We have chosen touch screen [2] over button and
switches because of less requirement of external pressure and
provides GUI interfaces. It is 4 wire resistive touch screen, as
we touch particular area on touch screen it will create
resistance difference between x and y layers and based on it
the position of touch can be decided that can be measured by
applying 5v dc to two ends of wires and measuring output
voltage with A/D converter and digital signal will be received
by microcontroller unit.

STM32F429 discovery board has inbuilt 2.4'' QVGA

TFT LCD with resolution of 240*320 and works based on
Fig. 2 Block diagram of transmitter section ARM processor [6][7]. Touch screen is two dimensional
device thereby touch digitizer coordinate system is used. In
portrait orientation, origin starts at upper left corner, with X as
horizontal and y as vertical. Code is created using KEIL
B. Software Implementation µvision5 for designing of GUI display and Reading X, Y
positions from touch screen. Code is designed for
STM32F429ZIT6 controller [7]. Have created different
functions using libraries available for stm32 created function
will wait for touch operation and when particular button on
touch screen is pressed, it returns X, Y co-ordinate
respectively. Vital code snippets are illustrated below in Fig.

Fig. 4 Code snippets of touch screen button logic

B. Obstacle avoidance feature

Here in this work hc-sr04 ultrasonic sensor is
implemented [1], it provides trig and echo pin for interfacing
Fig. 3 Flow chart of wheelchair system with any microcontroller. With the help of PIC we have sent
pulses to trig pin to take measurement, with help of pulse,
sensor will able to send ultrasonic waves. It will come back to
the sensor whenever obstacle is detected in permissible region.
 D. Implimentation Of Designed System
We require defining pins and by using TRIS register in
PIC will set TRIG pin as output and echo pin as input [5]. Our
target is creating function which will send pulse to trigger pin,
with the help of timer we can measure time by using start
timer and find rising edge on echo line whist will stop timer
when we get falling edge. Using this method we are able to
find out length of pulse in microseconds. By using time and
distance relation formula we are able to calculate distance of
obstacle from wheelchair.

Distance = (0.01718*time); we have set distance=15cm. (1)

C. Emergency Calling
For Emergency calling we are using second generation
mobile technology global system for mobile (GSM) [3]. GSM
module is interfaced with PIC16F877A [5] to dial a particular
Fig. 6 Developed wheelchair system
mobile number using AT command in Emergency situation.
The merit of using GSM module is we can directly interface it IV. FUTURE WORK AND CHALLENGES
with PIC controller without introducing any line converter to
The current research process emphasis is laid on
control rs232logic to TTL output. AT command is used to
overcoming the challenges to maintain the manufacturing cost
access data and configuration with respect to mobile devices,
and effective architecture. Future work will focuses on valid
SIM cards and modem.
implementation of Anti-breaking system and Emergency-
breaking system. Many factors like the weight of the user, the
age of the batteries, and the type of terrain being travelled can
influence the battery range, henceforth future work prioritizes
on enhancing functionalities which will allow to move them
without much interaction from user making it more
autonomous.
V. CONCLUSION
Four fundamental requirements for self-governing
operations for people with motor-impairments are Mobility,
Ambient control, Health monitoring and emergency handling
stands vital for transitioning to living independently. Blending
the four above enlisted fundamental requirements and the
solution presented in this paper will serve with great potential
in becoming solid solution for real life problems of the motor-
impaired. This proposed embedded system solution is not
limited to wheelchair implementation instead it can be further
modified and elevated to varied robotic vision development.
ACKNOWLEDGMENT
We express our sincere gratitude to colleague Riya
Rathod (department of computer engineering, Nirma
University) for helping out in research process by providing
useful information, valuable involvement in content writing
and contribution in this paper. We would like to specially
thank our parents for their valuable contribution in career
development.
REFERENCES

[1] Aye Aye Nwe, Wai Phyo Aung and Yin Mon Myint, 'Software
Implementation of Obstacle Detection and Avoidance System
for Wheeled Mobile Robot', World Academy of Science, Engineering and
Technology 42 2008

[2] M.Prathyusha , K. S. Roy , Mahaboob Ali Shaik ,Dept. of E.C.E, K. L.

University Guntur, India, Voice and Touch Screen Based Direction
and Speed Control of Wheel Chair for Physically Challenged Using Arduino,
International Journal of Engineering Trends and Technology (IJETT) -
Fig. 5 Flow chart of emergency calling feature Volume4Issue4- April 2013 , ISSN: 2231-5381
[3] Sayali Nerkar, Shweta Jadhav, Radhika Shouche, Sukanya Sonawani , " Android Based Vehicle Service Status Monitoring System" , International
Journal of Advanced Research in Electrical, Electronics and Instrumentation [6] Embedded Systems: Introduction to Arm(r) Cortex -M Microcontrollers,
Engineering , Vol. 3, Issue 2, February 2014 by Jonathan W Valvano

[4] "Embedded Systems “By Raj Kamal, Publication: Tata McGraw-Hill [7] The Definitive Guide to ARM® Cortex®-M3 and Cortex®-M4
Education, 2008 Processors, Third Edition 3rd Edition by Joseph Yiu

[5] PIC Microcontrollers, mikroelektronika, By Milan Verle, 1st edition

(2008), ISBN-13: 978-86-84417-15-4