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I have a NEMA17 stepper motor (2 Phase, Rated 12V, 1.2A/Phase) and I am trying to make it run with an L298N and a Raspberry Pi. Everything is wired up as shown below in the pictures. I use a 12V, 2A power supply to power the L298N. The RPi is powered separately.

I measured the resistance between the different stepper motor leads. I have been told that two wires are a pair if they have very little resistance. If there is no resistance, they are not a pair. This way, I think The correct pairs are in the A and B terminals of the L298N.

I'm using the following python script:

import RPi.GPIO as GPIO
import time

# Variables

delay = 0.05
steps = 50

GPIO.setmode(GPIO.BCM)
GPIO.setwarnings(False)

# Init pins

coil_A_1_pin = 9
coil_A_2_pin = 25
coil_B_1_pin = 11
coil_B_2_pin = 8

# Set pin states

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)

# Function for step sequence

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)


# Example rotations: forward and backward

for i in range(0, steps):
    setStep(1,0,1,0)
    time.sleep(delay)
    setStep(0,1,1,0)
    time.sleep(delay)
    setStep(0,1,0,1)
    time.sleep(delay)
    setStep(1,0,0,1)
    time.sleep(delay)

for i in range(0, steps):
    setStep(1,0,0,1)
    time.sleep(delay)
    setStep(0,1,0,1)
    time.sleep(delay)
    setStep(0,1,1,0)
    time.sleep(delay)
    setStep(1,0,1,0)
    time.sleep(delay)

The stepper motor does not move whatsoever, unfortunately. It does make very little noise when running the script.

Any ideas on how to troubleshoot this project are very welcome.

More details on the stepper motor:
PHASE : 2 PHASE
STEP ANGLE : 1.8 ± 5% ° /STEP
VOLTAGE : 12V
CURRENT : 1.2 A/PHASE
RESISTANCE : 10.0 ± 10% ?/PHASE
INDUCTANCE : 20 ± 20% mH/PHASE
HOLDING TORQUE : 48 N.cm Min
NUMBER OF LEADS : 4
LEAD STYLE : AWG26 UL1007
LEAD STYLE : AWG26 UL1007
ROTOR TORQUE : 68 g.cm2
INSULATION CLASS : B
SIZE : 41 x 41 x 62mm
WEIGHT : 181 grams

schematic

pic1

pic2

pic3

pic4

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closed as unclear what you're asking by Marcus Müller, Voltage Spike, Dmitry Grigoryev, Andrew, Bimpelrekkie Jan 31 '17 at 10:43

Please clarify your specific problem or add additional details to highlight exactly what you need. As it's currently written, it’s hard to tell exactly what you're asking. See the How to Ask page for help clarifying this question. If this question can be reworded to fit the rules in the help center, please edit the question.

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    \$\begingroup\$ And your schematic is.... \$\endgroup\$ – Tyler Jan 29 '17 at 0:01
  • \$\begingroup\$ Welcome, jvermeulen! as Tyler correctly indicates, a good question also includes a clear schematic of what you're doing – that's what the built-in schematic editor is for. \$\endgroup\$ – Marcus Müller Jan 29 '17 at 0:05
  • \$\begingroup\$ @MarcusMüller: A schematic has been added above. I hope it is clearer now! \$\endgroup\$ – jvermeulen Jan 29 '17 at 19:12
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    \$\begingroup\$ That is not a schematic, but it might be enough. \$\endgroup\$ – Tyler Jan 29 '17 at 19:12
  • \$\begingroup\$ @jvermeulen: that's really everything but a schematic (that's why I referred to the built-in schematic editor... sigh), but it certainly helps. \$\endgroup\$ – Marcus Müller Jan 29 '17 at 19:31
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I don't have the "reputation" to comment.....but, are the grounds (12-volt ground and Raspberry Pi ground) connected together? They must be!

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  • \$\begingroup\$ That was it! Thanks! I wonder, why is that necessary? Won't the current flow to the ground of the L298N instead of back to the raspberry pi? \$\endgroup\$ – jvermeulen Jan 29 '17 at 22:01
  • \$\begingroup\$ Current flows in a loop. A small current coming out of the Raspberry Pi must return somehow. The 12-volt supply is isolated from the AC socket that it is plugged into. Same for whatever is powering your Raspberry Pi. You must have a connection between the grounds. \$\endgroup\$ – whitegreg56 Jan 30 '17 at 20:42
  • \$\begingroup\$ But, when touching an electric fence, current does flow to your body through another ground, thus not circular. Why does current flow in that case, compared to this case? \$\endgroup\$ – jvermeulen Feb 1 '17 at 23:31
  • \$\begingroup\$ Any large conductive body can be considered to be a ground. \$\endgroup\$ – whitegreg56 Feb 3 '17 at 1:30
  • \$\begingroup\$ For example, planet earth. If you are still confused by all of this, consider starting a new question....we are getting off topic. \$\endgroup\$ – whitegreg56 Feb 3 '17 at 1:42

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