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Need help with DC motor control — Parallax Forums

Need help with DC motor control

SteelSteel Posts: 313
edited 2006-04-17 20:20 in General Discussion
Help!!!!

I know this sounds rather silly, but I am having issues with motor control.· I am running 2 DC motors.· They need to be fairly quick.· the 45mA is not enough from the BS2 port.· I looked into integrating this H-Bridge:
http://www.zetex.com/3.0/pdf/zhb6718.pdf

I am having issues all over the place. (my project is now shorting, and resets are occuring...)

So is there a low-part count solution for just turning off/on motors using the source voltage?· I would like them to pull the current and voltage from the source (5V, 1A) but be controlled by the BS2.· It must be very quick and controlled.·

I would appreciate any help.

Shaun

Comments

  • Jon WilliamsJon Williams Posts: 6,491
    edited 2006-04-17 18:02
    This part will save you a whole lot of trouble: http://www.parallax.com/detail.asp?product_id=30052

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    Jon Williams
    Applications Engineer, Parallax
  • Chris SavageChris Savage Parallax Engineering Posts: 14,406
    edited 2006-04-17 18:51
    45mA from the BS2 Port?!?· Were you trying to drive the motors directly from Stamp I/O pins?· Resets indicates that you're shorting the supply to the BASIC Stamp or at least browning it out.· Where are you getting power for the Stamp and Motors?

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    Chris Savage
    Parallax Tech Support
    csavage@parallax.com
  • SteelSteel Posts: 313
    edited 2006-04-17 20:05
    I'm not actually powering the motors from the BS2 I/O pins... I was just using that as a "I know I can't do" scenario.

    I disconnected the H-Bridges from my circuit, and there are no longer any brown-outs...but I am now trying the following method:

    I currently have a 74595 (Shift register) and a ULN2803AN darlington array...I was using this setup with Stepper motors on another project. I have the parts available, and I know they work so I think I'd rather implement them...

    Could I Bi-directionally control the DC motors by connecting the (+) and the (-) of the DC motor to the Outputs of the Darlington array?
  • Jon WilliamsJon Williams Posts: 6,491
    edited 2006-04-17 20:11
    No, the ULN2x03 can only sink curent; you can use the L293D to sink/source -- it works nicely as a DC motor driver.

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    Jon Williams
    Applications Engineer, Parallax
  • SteelSteel Posts: 313
    edited 2006-04-17 20:20
    Thanks, Jon
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