The DC motor is controlled by 4 relays for the movement of the wheelchair according to the current
commands received from the microcontroller. For front and
back movement; both DC motors are rotated in clockwise and
anticlockwise direction, respectively. For turning left, the left
motor moves anticlockwise and for right movement, right
motor moves clockwise on. Finally if an obstacle is to be
detected by ultrasonic detector, the microcontroller sends
signals to both DC motors to stop operating immediately. LCD
module is used to display the current command from the
microcontroller that is the project title, obstacle detected and
the five directional commands of the wheel chair.
The proposed automatic wheelchair can also be operated
with switch pad as follows. Press “1” (display shows “01” and
the LED turns off) on the keypad, then press the TRAIN key
(the LED turns on) to place circuit in training mode, for word
one. Say the target word into the onboard microphone (near
LED) clearly. The circuit signals acceptance of the voice input
intimated by blinking the LED off then on. The word (or
utterance) is now identified as the“01” word. If the LED did
not flash, start over by pressing “1” and then “TRAIN” key.
You may continue training new words in the circuit. Press “2”
then TRN to train the second word and so on. The circuit
accepts and recognizes up to 20 words (numbers 1 through 20).
It is not necessary to train all word spaces. If you only require
10 target words, all of them need to train.