Logic Chip Selection ... for a unipolar stepper motor

Hi All,

I am new to hardware design and robotics. I am a high school Physics/Chem teacher and we've been building a little arduino-driven robot. We have the arduino controlling a L298N driver for the two wheel motors, and we'd like to get a unipolar stepper motor (PF35T-48L4) connected to do some additional tasks.

While reading the Arduino Stepper Motor Configuration Lesson they suggest using a ULN2004A Darlington Array logic chip to drive a unipolar stepper motor. I don't have that Chip and it will take some time for approval, ordering, and shipping. I have a few other logic chips on hand, but I don't know if they will serve my purpose.

I suppose I have a couple of questions:

  1. Would any of the logic chips listed below stand in for the suggested one above.
  2. What knowledge do I need to be able to evaluate that on my own? How can I start to choose alternate chips for projects?
  3. Is the Darlington array essentially a higher-frequency version of the L298N with more pinouts? (if not for the need for high frequency, could the logic chip and L298N driver both be replaced by mechanical relays if solid state chips aren't available?)

Chips I have on hand:

  • 4 logic chips (SN74HC00N)
  • 4 logic chips (SN74HC02N)
  • 4 logic chips (SN74HC04N)
  • 4 logic chips (SN74HC08N)
  • 4 logic chips (HD74HC32P)
  • 4 logic chips (SN74HC86N)
  • 2 open-collector inverters ICs (SN7406N)
  • 2 triple-input NOR ICs (74LS27P)
  • 2 counter ICs (74LS92)
  • 4 counter /multiplier/divider logic ICs (CD4026BE)
  • 10 timers (NE555P)
  • 3 voltage regulator (L7805)

Thank you for the guidance!

None of the chips you mention are suitable to directly drive stepper motors.

However, for the price of a cup of coffee you can several sets of these unipolar stepper drivers. Less than USD $0.50 each. Each of the four outputs on a chip can handle 500 mA.

Do you have any MOSFETs or Transistors available? How much current are you switching?

I do have a few MOSFET's. It'll be drawing about 0.18 amps continuous, I'm not sure what the start-up draw might be.

Well, you will need 4 MOSFETs, 8 resistors and 4 diodes.
What are the part numbers of the MOSFETs?

You will probably need 2 N-Channel devices. Try for 2A or greater on the MOSFETs Using the UNO will keep things at 5V, much easier to find parts then if you were using 3V3. There is also a ULN2803 that would work.

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