1.3.1 Motor

Introduction

In this project, we will learn to how to use L293D to drive a DC motor and make it rotate clockwise and counterclockwise. Since the DC Motor needs a larger current, for safety purpose, here we use the Power Supply Module to supply motors.

Required Components

In this project, we need the following components.

../_images/list_1.3.1.png

It’s definitely convenient to buy a whole kit, here’s the link:

Name

ITEMS IN THIS KIT

LINK

Raphael Kit

337

Raphael Kit

You can also buy them separately from the links below.

COMPONENT INTRODUCTION

PURCHASE LINK

GPIO Extension Board

BUY

Breadboard

BUY

Jumper Wires

BUY

Power Supply Module

-

L293D

-

DC Motor

BUY

Schematic Diagram

Plug the power supply module in breadboard, and insert the jumper cap to pin of 5V, then it will output voltage of 5V. Connect pin 1 of L293D to GPIO22, and set it as high level. Connect pin2 to GPIO27, and pin7 to GPIO17, then set one pin high, while the other low. Thus you can change the motor’s rotation direction.

../_images/image336.png

Experimental Procedures

Step 1: Build the circuit.

../_images/image117.png

Note

The power module can apply a 9V battery with the 9V Battery Buckle in the kit. Insert the jumper cap of the power module into the 5V bus strips of the breadboard.

../_images/image118.jpeg

Step 2: Get into the folder of the code.

cd ~/raphael-kit/python

Step 3: Run.

sudo python3 1.3.1_Motor.py

As the code runs, the motor first rotates clockwise for 5s then stops for 5s, after that, it rotates anticlockwise for 5s; subsequently, the motor stops for 5s. This series of actions will be executed repeatedly.

Code

Note

You can Modify/Reset/Copy/Run/Stop the code below. But before that, you need to go to source code path like raphael-kit/python. After modifying the code, you can run it directly to see the effect.

import RPi.GPIO as GPIO
import time

# Set up pins
MotorPin1   = 17
MotorPin2   = 27
MotorEnable = 22

def setup():
    # Set the GPIO modes to BCM Numbering
    GPIO.setmode(GPIO.BCM)
    # Set pins to output
    GPIO.setup(MotorPin1, GPIO.OUT)
    GPIO.setup(MotorPin2, GPIO.OUT)
    GPIO.setup(MotorEnable, GPIO.OUT, initial=GPIO.LOW)

# Define a motor function to spin the motor
# direction should be
# 1(clockwise), 0(stop), -1(counterclockwise)
def motor(direction):
    # Clockwise
    if direction == 1:
        # Set direction
        GPIO.output(MotorPin1, GPIO.HIGH)
        GPIO.output(MotorPin2, GPIO.LOW)
        # Enable the motor
        GPIO.output(MotorEnable, GPIO.HIGH)
        print ("Clockwise")
    # Counterclockwise
    if direction == -1:
        # Set direction
        GPIO.output(MotorPin1, GPIO.LOW)
        GPIO.output(MotorPin2, GPIO.HIGH)
        # Enable the motor
        GPIO.output(MotorEnable, GPIO.HIGH)
        print ("Counterclockwise")
    # Stop
    if direction == 0:
        # Disable the motor
        GPIO.output(MotorEnable, GPIO.LOW)
        print ("Stop")

def main():
    # Define a dictionary to make the script more readable
    # CW as clockwise, CCW as counterclockwise, STOP as stop
    directions = {'CW': 1, 'CCW': -1, 'STOP': 0}
    while True:
        # Clockwise
        motor(directions['CW'])
        time.sleep(5)
        # Stop
        motor(directions['STOP'])
        time.sleep(5)
        # Anticlockwise
        motor(directions['CCW'])
        time.sleep(5)
        # Stop
        motor(directions['STOP'])
        time.sleep(5)

def destroy():
    # Stop the motor
    GPIO.output(MotorEnable, GPIO.LOW)
    # Release resource
    GPIO.cleanup()

# If run this script directly, do:
if __name__ == '__main__':
    setup()
    try:
        main()
    # When 'Ctrl+C' is pressed, the program
    # destroy() will be executed.
    except KeyboardInterrupt:
        destroy()

Code Explanation

def motor(direction):
    # Clockwise
    if direction == 1:
        # Set direction
        GPIO.output(MotorPin1, GPIO.HIGH)
        GPIO.output(MotorPin2, GPIO.LOW)
        # Enable the motor
        GPIO.output(MotorEnable, GPIO.HIGH)
        print ("Clockwise")
...

Create a function, motor() whose variable is direction. As the condition that direction=1 is met, the motor rotates clockwise; when direction=-1, the motor rotates anticlockwise; and under the condition that direction=0, it stops rotating.

def main():
    # Define a dictionary to make the script more readable
    # CW as clockwise, CCW as counterclockwise, STOP as stop
    directions = {'CW': 1, 'CCW': -1, 'STOP': 0}
    while True:
        # Clockwise
        motor(directions['CW'])
        time.sleep(5)
        # Stop
        motor(directions['STOP'])
        time.sleep(5)
        # Anticlockwise
        motor(directions['CCW'])
        time.sleep(5)
        # Stop
        motor(directions['STOP'])
        time.sleep(5)

In the main() function, create an array, directions[], in which CW is equal to 1, the value of CCW is -1, and the number 0 refers to Stop.

As the code runs, the motor first rotates clockwise for 5s then stop for 5s, after that, it rotates anticlockwise for 5s; subsequently, the motor stops for 5s. This series of actions will be executed repeatedly.

Now, you should see the motor blade rotating.

Phenomenon Picture

../_images/image119.jpeg