View Full Version : Controlling Stepper from 3-1/2 floppy drive

02-11-2006, 12:01 AM
Hi all!

This is my first post here. Let me tell you about my project first. I am building a robotic eye which is a combination of
motion detection and motion control. This "eye" is supposed
to follow the moving object in the background (single moving
object to oversimplify the things)

I am very new to this. After a lots of research and reading,
I decided to take out the stepper motor from the floppy drive.
But it was a little different from the ones that I had read
about. The motors I read about had 5 wires (1 common and other
4 for the 4 half coil). This motor has only 4 of them. The
floppy drive is from sony. I am bit confused regarding this.
Is the body of the motor the common ground? The circuit I am
following is here:

I am doing this for the first time. Any help as to where the
fifth wire is? :)


02-11-2006, 12:48 AM
Hey if your motor has 4 wires then it must be a bi-polar one. Just search the net for "bipolar stepper motors" and you will get many circuits and sequences and answers to all your other queries.

02-11-2006, 03:33 AM
Mainly steppers are of 4,5,6 leads

4- only bipolar stepper
5- only unipolar stepper
6- both unipolar as well as bipolar.

So your's is bidirectional. Use L297 + L298 to drive that stepper motor. Bipolar steppers have good torque

Bibin John

02-11-2006, 12:38 PM

Thanks! I found another circuit without much effort.

The tiny stepper motor I took out from the drive hasn't any current
ratings on it? Do these motors have standard current requirements.
If so, what should be the current ratin for this one?


02-11-2006, 07:59 PM
the shaft of the floppy stepper does not stay porperly in place once you remove it from the drive. moreover those steppers are not powerful enough to turn a camera. buy a printer stepper from a scrap dealer, if ur frm mumbai pm me for the address.

02-11-2006, 11:39 PM

I also doing a project in robotics. I saw a circuit using
IC for controlling the stepper from a floppy drive in
EFY magazine-April 2004.

02-12-2006, 01:19 PM

I am moving ahead with the circuit that I mentioned in the
previous post!

Thanks for your help!


08-30-2007, 11:49 PM
Hello sir,

We are building a micromouse using stepper motors. We have 2 stepper motors with following ratings-
1. 3.5V , 0.7A
2. 3.8V , 0.67A

The ratings of the two motors are different and we have to overdrive the motors at around 12V.
For that purpose we are using IC SLA7024M (ALLEGRO MICROSYSTEMS) which is a PWM CHOPPER
So, we are facing certain difficulties,plzz help to sort them out.

1. Can we overdrive the stepper motor of this rating at 12V?
2. Which IC is better to use for driving it-IC SLA7024M or IC UCN5804B?
3. If using IC SLA7024M , how the current through stepper motor is to be controlled?
4. Will the different ratings of the two stepper motors affect the response much?

thanxx a lott............