The original floppy disk drive for IBM-PCs and compatibles was the Tandon TM100. When we scrapped a lot of old IBM-PCs, I kept the disk drives to see if I could make use of any of the components. Of particular interest to me were the stepper motors.

These were made by a number of companies including

• Tandon themselves and Japan Servo Motors - type KP4M4-001
• Minebea Co., Ltd - type 17PS-C007-04
• Shinano Kenshi Co., Ltd - type STH-42G100

They all have the same specs: +12v dc, four-phase, unipolar, 3.6° per step.

With the arrival of PC clones and half-height drives, lots of other stepper motors came into use.

There are various ways to get these motors going, controlled via the digital outputs of a PC's Parallel Printer Port or with a microcontroller such as the PIC or BASIC Stamp

• Using the Disk Drive's own Logic PCB, which includes all the control circuitry required. Here's a possible cable design and some software

  I've gone off that idea, in favour of

• Using an array of Darlington transistor pairs on a chip to switch current to the coils in the motor. To do this you will have to generate the stepping sequences yourself. Here are some possible connection diagrams and some software

  Or, alternatively

• Using a driver chip such as the UCN5804B from Allegro MicroSystems, Inc. Here is a possible connection diagram and control information.

• StoneAge DiskDrive Logo Turtles

• Pan-and-Tilt Mount for a Camera

• Combine them into a Mobile Mount for a Camera

  (What these need is a good SMACK - maybe like this one)

• Dan Bruton's Satellite Tracking Device

• Mel Bartel's Motorize Your Telescope

• Diana Todd's Hand Scanning Automation project

• Dan Mathias' Robotic Creations include The P-Bot and The Floppy-Bot

• Fran Golden's "Floppy" the Robot (uses the dc motor)

• Luberth Dijkman's Home build Hobby Plotter/Engraver

• Alan Quinn's Desktop CNC Drill

• UWA's Genesis Site includes an Electronic Puppet

• Micromouse Information Centre Stepper Motors

• Vince Long's Recycled Computer Parts Turned Into Robots (PDF) article in MCCE News, Spring 2002

• Tony Mercer's Basic Stepper motor concepts - A tutorial on basic electromagnetism and how it applies to stepper motors

• Douglas W. Jones' Control of Stepping Motors, a tutorial

• Jason Johnson's Working With Stepper Motors

• Stepping Motor Tutorial from SIG POSITEC UK

• The Stepper Motor Archive from Wirz Electronics

• Application Note 235 from SGS-Thomson covers both unipolar and bipolar stepper motors

• Ericsson has a number of Application Notes available, including Stepper Motor Basics and Drive circuit basics

• Motionex's Compumotor Catalog Engineering Reference Guide includes documents on Step Motor Technology and Step Motor Drive Technology

• Stepper Motor section of EDUCYPEDIA, The educational encyclopedia

• Links to the World's Largest Robotics Sites at Android World

• More Controller Information and some Commercial Products

last updated: 24-Feb-03 Ian Harries <ih@doc.ic.ac.uk>