Stepper Motor Control with the Raspberry Pi 3 model b v1.2 with L293D

Question

I want to move a motor with raspberry pi... here is my work I followed this example

This is my raspberry pi 3 model b v1.2

import RPi.GPIO as GPIO
import time

GPIO.setmode(GPIO.BCM)
GPIO.setwarnings(False)
coil_A_1_pin = 4 # pink
coil_A_2_pin = 17 # orange
coil_B_1_pin = 23 # blue
coil_B_2_pin = 24 # yellow
// adjust if different
StepCount = 8
Seq = range(0, StepCount)
Seq[0] = [0,1,0,0]
Seq[1] = [0,1,0,1]
Seq[2] = [0,0,0,1]
Seq[3] = [1,0,0,1]
Seq[4] = [1,0,0,0]
Seq[5] = [1,0,1,0]
Seq[6] = [0,0,1,0]
Seq[7] = [0,1,1,0]

GPIO.setup(enable_pin, GPIO.OUT)
GPIO.setup(coil_A_1_pin, GPIO.OUT)
GPIO.setup(coil_A_2_pin, GPIO.OUT)
GPIO.setup(coil_B_1_pin, GPIO.OUT)
GPIO.setup(coil_B_2_pin, GPIO.OUT)

GPIO.output(enable_pin, 1)

def setStep(w1, w2, w3, w4):
GPIO.output(coil_A_1_pin, w1)
GPIO.output(coil_A_2_pin, w2)
GPIO.output(coil_B_1_pin, w3)
GPIO.output(coil_B_2_pin, w4)

def forward(delay, steps):
for i in range(steps):
    for j in range(StepCount):
        setStep(Seq[j][0], Seq[j][1], Seq[j][2], Seq[j][3])
        time.sleep(delay)

def backwards(delay, steps):
for i in range(steps):
    for j in reversed(range(StepCount)):
        setStep(Seq[j][0], Seq[j][1], Seq[j][2], Seq[j][3])
        time.sleep(delay)

if __name__ == '__main__':
while True:
    delay = raw_input("Time Delay (ms)?")
    steps = raw_input("How many steps forward? ")
    forward(int(delay) / 1000.0, int(steps))
    steps = raw_input("How many steps backwards? ")
    backwards(int(delay) / 1000.0, int(steps))

i got this error :

"Traceback (most recent call last):
File "stepper.y", line 23, in <module>
GPIO.setup(enable_pin, GPIO.OUT)
NameError: name 'enable_pin' is not defined"

Answer 1

Edit : this answer is working for the ULN2803A chip, question has been edited since for another chip.

enable_pin definition is missing in your code. Something like this may have been added just after the import section to solve the issue : enable_pin=18

A better solution is to remove the :
GPIO.setup(enable_pin, GPIO.OUT) and
GPIO.output(enable_pin, 1) lines, as this pin is not connected with the ULN2803A chip.

This pin configuraton was only provided in the adafruit tutorial for compatibility with other stepper chips.

Answer 2

It seems the chip you are using : L293D is not the one in the shematic you provided.

You need to connect your components like this : https://learn.adafruit.com/adafruits-raspberry-pi-lesson-10-stepper-motors/hardware-l293d

With this chip, you also need to define the enable_pin in your code. Add this just after the import section:
enable_pin=18
And everything will go fine :)