The prototype system implementation of proposed speech
controlled automatic wheelchair is shown in Fig 6. The
prototype system is implemented on small wooden chair.
Ultrasonic sensor is interfaced with the microcontroller that
work on a principle similar to radar or sonar which evaluate
attributes of a target by interpreting the echoes from radio or
sound waves respectively .In this project, ultrasonic sensor is
used to detect obstacles and calculate the distance from the
wheelchair and switch off the movement immediately. The DC
motors are fixed under the back wheeled foot of chair to drive
in different direction. The speech recognitions, driver interface,
microcontroller, ultrasonic sensor and power supply modules
are implemented with the diagrams discussed in section II. The
microcontroller is programmed to drive the DC motors in
clockwise and anticlockwise direction based on the
requirement. The DC motor is controlled by 4 relays for the