Question

Speed control of DC motor by PWM (Pulse Width Modulation), Python Program.

Answer 1

L293D motor driver IC is used to control the DC Motor and that allows the motor to rotate in both the direction. 2 DC Motors can be controlled with a single L293D motor driver IC as describe in DC Motor Control With Raspberry Pi and L293D. Here we are using single motor to understand the concept of PWM.

PWM (Pulse Width Modulation) concept is used to control the speed of Motor.

Python Program

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import RPi.GPIO as GPIO import time GPIO.setmode(GPIO.BOARD) GPIO.setup(5,GPIO.OUT) #Motor input A for clockwise direction GPIO.setup(7,GPIO.OUT) #Motor input B for anticlockwise direction GPIO.setup(40,GPIO.OUT)  # for enable the Motor GPIO.setwarnings(False) i=0 pwm=GPIO.PWM(40,100) #Apply PWM to enable PIN (PIN no. 40 here) pwm.start(0) #Start PWM with 0 Duty Cycle. while i<1:         for x in range(0,100,10):                 pwm.ChangeDutyCycle(x) # increase duty cycle or motor speed from 0 to 100 by  the interval of 10                 print("Duty_Cycle or motor speed is:",x)                 print("Rotating motor in clockwise direction with increase in speed by the interval  of 10")                 GPIO.output(5,0)                 GPIO.output(7,1)                 time.sleep(5)     #Five second delay         for x in range(100,0,-10):                 pwm.ChangeDutyCycle(x) # decrease duty cycle or motor speed from 100 to 0 by the interval of 10                 print("Rotating Motor in anticlockwise direction with decrease in speed by the interval of 10")                 GPIO.output(5,0)                 GPIO.output(7,1)                 time.sleep(5)     #Five second delay          i=i+1