I have been struggling with this as I'm a complete electronics and arduino beginner. I am trying to power two DVD-drive stepper motors using two L298N motor boards.

For some reason, I can't figure out how to power them using external source.

I can connect one like this straight from the arduino and the motor spins properly:

enter image description here

I know this is bad because it could damage the arduino etc, so I tried to provide a separate power supply to the motor, which in this case is an iphone wall charger which provides 5V, 1A. I also tried with a power bank that supplies 5V, 1A. I wired it up like this but then the motors don't run:

enter image description here

I don't know what I am doing wrong. Any help would be greatly appreciated.

  • Your schematics don't show how you have connected the motors. And it doesn't show how the Arduino is connected to the motor-board. Also, steppers will require you to "make steps" and you'll need some code along with it. – Paul May 3 '16 at 17:55
  • I left out the motors because they work fine and is not the issue here. They work fine when connected using the first picture. – user20551 May 3 '16 at 18:19
  • The L298 is a fairly obsolete part which has huge internal losses - if you give it 5v, you will get only a little over 3v across a motor. In your second case, are you powering the Arduino at all? – Chris Stratton May 3 '16 at 18:26
  • Oh I see. I am powering the arduino via usb. – user20551 May 3 '16 at 18:30
  • 4
    I'm voting to close this question as off-topic because it is about the Electrical Aspects of unidentified stepper motors, not about Arduino. – Chris Stratton Jul 2 '17 at 14:33

If your second schematic correctly represents your actual wiring, the problem is that you are connecting the arduino 5V pin (instead of the GND pin) to the L298 GND.

I assume you have also connected the control pins of the motor controllers to Arduino pins?

  • I have indeed connected the control pins. I suspect one of my motor boards is faulty, I am going to get a new one and try again. Thanks for your suggestion. – user20551 May 5 '16 at 12:59

First thing is to check the voltage of the motors. If it is 12V then you can use 12 V external power supply both to power arduino uno and motor using any DC regulated 12V source. Arduino UNO has input voltage range of (7-12 V) so it will not harm.

If you have 5V motors then you can power motor with arduino itself .

But i recommend to choose external source of 5V or 12V and use 7805 voltage regulator in any case if you need.

According to my knowledge, one L293N can be used to drive 2 motors.