Fun with floppy stepper and driver

[Konstantin]

Hi all again.
You know I kind of feeling lonely here. I post and I post and ppl just read the post and sez nothing, at least drop a few lines like "Keep it up" or "Hi there, I dont know nothing about the subject, keep trying". Lend me a shoulder here please *snif* *snif*

Ok back to the topic.

While I am learning about steppers and I have aquired a small amout of old junk computer hardware and lately been using floppy disk drive parts to drive the stepper that was in the drive. It was a 5 1/4 old floppy drive with the electronics and the stepper in good shape.
Since I have no regular driver board yet and I have some salvaged steppers from disk drives and printers I dicided to experiment using its own floppy's stepper driver.

So using the information from this sites ...

Pinouts : http://www.doc.ic.ac.uk/~ih/doc/stepper/tm100/
Program : http://jewel.morgan.edu/~tmalone/dskdrv/dskdrv.html

... and a bit of tweaking I found that my particular floppy drive uses pin 12 to select the head stepper , pin 16 to power the stepper , pin 18 as direction and pin 20 to step.
So I hooked up the driver board to my LPT using
LPT pin 2 to driver board 20 step
LPT pin 3 to driver board 18 direction
LPT pin 20 to driver board GND

The floppy driver turns the stepper to 'home' position on boot up and I am yet to figure out how to remove that feature, there are lots of jumpers on the driver board tho I cant tell what they do.


So far I have only found those small programs written in C (link above) and tried to run them with mixed success. The last program named DSKDRV3 works for me partially. The first part of the program suppose to turn the stepper clockwise and it just vibrates without moving, then the pause and after it do turns clockwise while it suppose to run CCW.

I dont remember much about programming but can compile the program on Turbo C 2.

Anybody used floppy drive steppers?

[abasir]

Konstantin,
Don't be disheartened by the lack of response. From what I gather, most members here are CNC-centric. They are some of us who are also electronically inclined (and little money) and do our own testing. I've use floppy steppers before but not using the original driver board. It's too cumbersome to program and you cannot use 'normal' stepper controller software.

If you can find unipolar motor from the floppy, I have 10 of them with 5 wires, then your prototyping would be significantly easy. Just connect few transistors and resistor and you are set to use TurboCNC/KCam using wave-drive. Then you would be able to quickly come up with workable system.

Just drop me a line if you need some more help

[Mr.Chips]

Konstantin
I don't have any experience with stepper motors from floppy drives, and don't remember anyone using them as a stepper motor on this site.
Seems I have seen links on the internet of people that have used them but I don't know where.
Sorry couldn't have been of more help
Hager

[Hobbiest]

I have wired electrical systems in cars from scratch, but the EE of PCB (accronyms rock!) is way out of my league! Right now anyway! Being a scrounger who builds cars, bikes, and machines from garbage and junkyard stuff, I think it is totally cool that you have figured out these floppy steppers! Now you need to build a small machine using all printer and scanner parts for the ways, and floppy steppers for the motion. Scanners have a moving carriage, that is like 10" wide, and I think would maybe be used for some cool proopf of concept type of design!

[Konstantin]

I think I am on the right track with this stepper driver.
Abasir: yes the stepper I have is unipolar.

The driver board DO works properly. I have found the problem. The problem was that the instructions that were run by the program were not all good for my driver board. I think that this driver needs the step pulse to be at least 50ms and since only the latter part of the code was executed properly then checked the code and found that the first part used 25ms timing.
From http://jewel.morgan.edu/~tmalone/dskdrv/dskdrv.html

File COMMAND.DAT. This ASCII file is prepared by the user to control the motor as required to perform a task. T 0 25 5000 /* turn one way fast for 5000 ms */ P 5000 /* pause for 5000 ms */ T 1 50 5000 /* turn other way for 5000 ms */ Q /*quit*/

First line uses 'T 0 25 5000' 25ms step pulse wich the driver board did not support, that is why I had vibration instead. Now that I changed it to 50ms the little program does make it turn one way and then another so I think the driver works.

T 0 50 5000 /* turn one way fast for 5000 ms */ P 5000 /* pause for 5000 ms */ T 1 50 5000 /* turn other way for 5000 ms */ Q /*quit*/

What is the timing on a 'normal' stepper driver?

Now that I know this works, maybe a bit too slow but nevertheless for my learning purposes, what should I do next?

I have this 'black hole' in my head about interfacing the driver board to software, so here I have now a working 1 stepper setup using LPT pins 2 and 3 for step and direction, Id like to hook it up to a commercial program. Later I could add another axis from another floppy drive to make a XY table.
I am going to dl a demo of TurboCNC/KCam if there is any and try to do something.

Konstantin.
PS
Now a bit off topic, I salvaged this magnificent Maxtor 148 MB hard drive from a i386 20MHz server, the housing is full tower and it weights alot. Look at these 8 HD platters, 17.5 MB each plate. The whole thing is pretty heavy. Look at the size of that thing. After I remove the the platters and the voice coil I could do a jewlery box out of it.
I hope I can engrave those platters for a clock sometime, whould make a hell of a clock.

[abasir]

>>> What is the timing on a 'normal' stepper driver?

There's no 'normal'. It all depends on the voltage applied & the motor's dynamics & loads. On my DIY, it's running at about 5000pps -> 0.2ms per step at max speed.