stepper motor driver

Discussion in 'General Electronics Chat' started by electronis whiz, Jun 12, 2013.

  1. electronis whiz

    Thread Starter Well-Known Member

    Jul 29, 2010
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    I have a bunch of stepper motors, but no way to run them. looking at controllers online ebay, amazon, etc. most i'm seeing look like need external pulse source. I don't know how to make circuit for that or what frequency is needed. i'd make from controller chip, but has conections to other chips for control I would guess, and no idea how to trigger and think since from printer only work 1 way.
    how would I make a pulse source? and ones with all functions seem hard to find. like something for like few A 2-15V.
     
  2. atferrari

    AAC Fanatic!

    Jan 6, 2004
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    The first time, I went the simple way: a micro outputting sequentially to get full step rotation. Later I did half stepping.

    The motor was driven by transistors.

    Later I used the local equivalent of an L293 (from the top of my head thus I could be wrong).

    Learnt what is resonance when found that at certain speed there was NO speed but noise...!

    Currently available driver chips (the most modern) are quite sophisticated, SMD, probably requiring 3,3 V or about, expensive and could require parallel, serial or I2C communication.

    Once you learn the basics by doing what I did, you could use them with confidence.

    Oh sorry, are you going to use a micro?

    Sorry for those traditional guys out there but going with logic gates is good to learn but far from practical.

    My last design was made using the circuit controlling an EPSON printer (LX850). After a long session of reverse engineering and some careful brain surgery I replaced their micro with my 18F and steppers did well.

    If you are interested and can get your hands on their technical manual, you could learn what a good design it was.

    Have you Googled on the subject? My best was a clasic: "Jones- steppers."

    Read it carefully and then make your own way. To minimize troubles and eventual "smoking" use the smallest steppers you could. LIke those in floppy drives used to move the writing head.

    I am not sure what is "one way" related to printers but steppers move back and forth at an incredible speed. Peek inside when they carry their internal test...

    Buena suerte.
     
  3. electronis whiz

    Thread Starter Well-Known Member

    Jul 29, 2010
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    I have small steppers, I just pulled a fist sized 5V unipolar one from a printer.
    I was looking at bipolar driver kits and ready made ones since they run both uni and bipolar.
    I could make one though found driver chip from printer. it is an SLA7024M
    found spec here, but understand only little bit if pin designations. http://pdf1.alldatasheet.com/datash...A7024M/+_43Q8UNpIEhyRdVPhENCEX+/datasheet.pdf
    only meant for like 1.5A, but think could add transistors to make handle more if needed.
    I see some caps, resistor hooked to some leads. and some go out a connector that joins a logic board and goes to some IC. 4 go off to the motor connector, and a few go to a transformer with only 1 winding used guessing inductor or current limiting.
    think wouldn't be hard to trigger this chip, but not sure how.
     
  4. atferrari

    AAC Fanatic!

    Jan 6, 2004
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    If you read the datasheet, the signals required to rotate a motor are explained in a table.
     
  5. electronis whiz

    Thread Starter Well-Known Member

    Jul 29, 2010
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    I see the tables you mean, but don't understand what they mean. was hoping to get a schematic of what external parts I need to make this work.
     
  6. atferrari

    AAC Fanatic!

    Jan 6, 2004
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    Quoting myself:

    I insist: are you?

    I insist: have you?

    There was a section explaining the basic of circuits. I started from there.

    Additional detail: once you implement the circuit, test it as a full step one.
    You can provide the signal to each transistor in the sequence you like at your own pace. A breadboard is enough.

    If NPN, use pull down resistors at the base of each one so you have to provide logic 1s only.

    Exactly my problem before I read Jones.
     
  7. mongause

    New Member

    Jun 9, 2013
    5
    1
    You might try a L298 stepper controller from ebay for $4 apiece. They have two digital pins per winding, 4 on the entire board. If you put a not gate on one pin on each side, you only need two wires to send it the control signals.
    I just discovered today that HAL (part of LinuxCNC) can send the quadrature signals needed to make the motor turn with only two signals.
    Btw, the stepper motors I use came out of an industrial label printer which only turned one way. They have no problem going both ways.
    The next time I try to build from scratch will be when I use my mill to carve up a pc board to install newly purchased parts on. But I'm glad I went the junk route first because I understand what's going on much better than I would have otherwise.
     
  8. Aiman Mirza

    New Member

    May 23, 2013
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    Well I guess to run ur stepper in a full step angle mode u can use shift registers instead of using any μp as it gives the pulses required for full mode..
    Provide these pulse to l298 or h bridge with the supply(vss) of 12v @2A..
     
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