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I am following this tutorial for a CNC laser engraver. I have two stepper motors from some old DVD drives and two L9110S H-bridges to control them.

I am now working on putting it all together and ran into some confusion when setting up the power supply for which I cannot find much information on within the guide. Could I connect the 5V at pin 2 of the RPi to both the H-Bridges to run the stepper motors or will I need to look at an external power supply for this? If external, what could I use? I have seen examples of 4 AA batteries in series, will this do the job?

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  • \$\begingroup\$ I presume that the stepper motor specs will be similar to this: robocup.idi.ntnu.no/wiki/images/c/c6/PL15S020.pdf \$\endgroup\$
    – Rahul Khosla
    Commented Oct 11, 2014 at 15:11
  • \$\begingroup\$ No, you definitely do not want to power motors through a microcontroller board such as the raspberry pi. Batteries are likely to lead to short and unreliable operation and expense - unless your goal is to make a portable device, why bother? Many desktop/experimental motion systems use surplus laptop or desktop computer power supplies. \$\endgroup\$
    – Chris Stratton
    Commented Nov 12, 2014 at 19:28

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I'm not familiar with the raspberry-pi, but there's a good chance the stepper motors draw more current than the GPIO pins can supply. It's better to supply these motors with their own power supply.

Depending on what voltage your motors require, you can use AA batteries. If the motors require lots of current, you may be better of using a LiPo battery of the appropriate voltage instead.

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