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Author Topic: Stepper Motor Knob tutorial problem  (Read 2328 times)
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Hello, I am trying to complete the stepper motor knob tutorial out of the arduino stepper library.  I am using a SN754410ne H-Bridge, arduino uno, and a stepper motor from a scanner.  The motor is labeled Mitsumi M42SP-4NP  6ohms.  I am using a 12VDC 2.0A power supply for the motor.  The wires brown and black go to one coil and red yellow to the other coil.  I have tried every possible combination for the two pairs of wires going to the motor  from the h-bridge and just get a little different pattern of wiggle each time.

problem:  motor will not spin it just wiggles back and forth

schematic and code: http://www.arduino.cc/en/Tutorial/MotorKnob

picture of my setup: http://s1091.photobucket.com/albums/i396/jafranswa/?action=view&current=photo8.jpg

I plan to adapt this setup for an arduino mega and infrared proximity sensors with several motors inside a sculpture in time.  But this would be step one.
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if it just sits there and wiggles it may be that one pole or the other is out of phase.  Reverse the leads on ONE phase and see if that helps.
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When the testing is complete there will be... cake.

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I tried switching one pair of wires.  I even put them back and then tried switching the other pair.  In either case it just wiggled.  I even tried a different and smaller motor.  It had the same issue but the smaller motor would turn some but mostly wiggle. I'm pretty confused by this.
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Try running the motor at a slower speed. It can do this if you are trying to go too fast.
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Having the same issue, tried switching phases and speed down. The failure mode is it tries to turn but just clicks instead of doing a step.
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Thanks for the help so far guys but I tried slowing down the speed of the motor to as little as 10 rpm with the same results. the motor just wiggles.  I have also tried reversing the wires for one coil. Is it possible there is something wrong with the code?  It is from the example.  All I have changed in it is the # of steps in the motor and the rpm. 
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Maybe this thread can help you

http://arduino.cc/forum/index.php/topic,66352.0.html
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10 RPM is still quite fast depending on the motor and the voltage you are driving it from, take it right down.
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I managed to get this working with a transistor array uln2004a and a unipolar stepper motor.  I am currently running the motor off of 9vdc.  This motor may just not have enough torque to do what i want but it does seem pretty week sauce and has trouble with much more than 25 rpm.  I was wondering if I could get more out of it just by bumping the voltage up to 12vdc or maybe even 32vdc (max for my chip without running 2 chips parallel).  Also is it possible the code i am using just doesn't take full advantage of the torque the motor is capable of my micro stepping or properly using both coils?  I realize that is at least three questions but i guess I am a little green.


Thanks again for all the help
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Also is it possible the code i am using just doesn't take full advantage of the torque the motor is capable of my micro stepping or properly using both coils
No, micro stepping produces less torque not more.

Quote
or maybe even 32vdc (max for my chip without running 2 chips parallel).
Alarm bells - I think you are fundamentally misunderstanding something here. Running two in parallel can give you more current not voltage.

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I was wondering if I could get more out of it just by bumping the voltage up to 12vdc
Yes you can get it to go faster with more voltage. However there will be more current and the motor will get hotter. The way round this is to use a limiting regulator that monitors the current and cuts off the voltage when this is reached. Then you can over voltage the motor for speed without over heating the motor.
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