"Manual" control of stepper motor?

[TheDarkLord]

Hi everyone,

I'm looking to control a stepper motor (from an old floppy disk drive-with worm gear attached) without the use of a microcontroller or a commercial stepper motor controller. There would need to be two push buttons - one which will turn the stepper motor in one direction and the other in the other. I want the motor to spin continuously while either button is pushed down. A potentiometer for speed control would be good, but not wholly necessary. Accuracy is not important, though I would like the rotation to be as smooth as possible. I was wondering if there is a possible solution to this using, say, a 555 timer or other easily available IC's. Though I may add this onto a project later on, for now it is just intended to be a learning experience for me.

Any advice, schematics, links, or pointers would be greatly appreciated.

Thanks,
VR

[Admin]

The easiest way is to use a stepper motor controller

Why do you not want to use an mcu or driver?

[TheDarkLord]

Well I was thinking that there may be a relatively straightforward alternative using minimal circuitry (though Google showed no satisfactory results); like I said this is just for my learning experience 

[Admin]

You can get a cheap stepper motor driver chip/board, then use a rotary encoder (plus a few resistors) to trigger the steps.

Or you can hook up a 555 timer with a button, as you mentioned, to the step pin of the motor driver.

[waltr]

It could be done but would take a lot of circuity.
Which type of Stepper, Bi-polar or Uni-polar?
The former requires two H-bride drives whereas a latter only requires four single ended drivers.

And a 555 could provide the pulsing you still need circuits to provide the phase timing to each stepper motor coil. This is way a processor and driver chip is the modern solution that uses the minimum number of parts.

[TheDarkLord]

I may be wrong, but it is a bipolar motor - it has 4 leads coming out of it.
Hmm, thank you for the input.

I just managed to find this schematic online (http://www.555-timer-circuits.com/stepper-motor-controller.html) but judging from what I've been told it may be too good to be true. Would you mind taking a look at it and telling me whether or not it would work?

Thanks,
VR

[Admin]

I have no idea what a TE555-1 is . . . I can't find it in the normal places, and that pin-out doesn't match a typical 555.

[Pogertt]

It seems the te555-1 is a rebranded pic 12f629.

http://forum.allaboutcircuits.com/showthread.php?t=59993

Pogertt

[Soeren]

Hi,

I'm looking to control a stepper motor (from an old floppy disk drive-with worm gear attached) without the use of a microcontroller or a commercial stepper motor controller. There would need to be two push buttons - one which will turn the stepper motor in one direction and the other in the other. I want the motor to spin continuously while either button is pushed down. A potentiometer for speed control would be good, but not wholly necessary.

Sounds like you need an L297 (stepper controller) and an L298 (stepper power driver) driven from eg. a 555
Google the datasheets of the L297 and L298, they have schematics of how to connect them.

It can be done reasonably simple with logics, although a unipolar motor is so much easier to drive (that's what the TE-555 drives and it has nothing to do with a 555).
For a bipolar stepper, you need h-bridges for both windings. The L297/L298 takes all the work outof it and adds full/half step capability, chopper current limiter and what not, so makes short work of a stepper controller.

Back in the early eighties, I made stepper controllers in EPROMs, but unless you have a way to burn them, that might be expensive (and you still need to add current drivers).

[TheDarkLord]

Ah okay, thank you all for the replies, I guess I'm going to go with the L297/L298 combination!