Description
At the simplest level, these stepper motors can be driven by issuing successive step commands via the IBM-PC parallel printer port using a Darlington driver array chip.

This takes time and ties up processing power on the host. A control board that accepts single commands over a serial connection would be more efficient and useable with most contemporary computers.

Applications might include

• Static devices, such as a Pan-and-Tilt Mount for a camera
• Mobile devices, such as Logo Turtles
  etc

Requirements
To produce a microcontroller-based control board that accepts a range of motor commands via an RS-232 interface. The functionality could include

• Single- and two-coil excitation and half-stepping selection
• Direction (clockwise/anticlockwise) selection
• Reset (return to initial position)
• Multiple step, returning number of steps actually executed
• Absolute as well as incremental moves.
• Ramping, for optimal high-speed performance
• Interleaving (simultaneous stepping) of multiple motors
• Faster/slower speed selection
• Free running
  etc

Also libraries of I/O routines with simple demo programs for a variety of host computers and development environments.

A possible enhancement would be the ability to "daisychain" a number of boards, allowing control of more motors.

Reference
Stepper Motors • PIC Microcontrollers

MEng Individual Project Summary June 98

• JVL develop and produce a wide range of versatile, high quality integrated servo motors and integrated stepper motors.

• SSC Stepper Motor Control System from Eggert Electronics Engineering

• DEV-STEP Stepping Motor Controller from Devantech Ltd

• XYYZ CNC Stepper Motor Controller from Super Tech & Associates

• Dave Rigotti's Hobby CNC page

• Indexer LPT multi axis step motor controller from Ability Systems Corporation

• MD-2 Stepper Motor Control Systems from Arrick Robotics

• StepperControl.Com for your stepper motor controller application needs

• Motor Driver Board from WZ Micro

• STP100 Stepper Motor Controller from Pontech

• The Little Step-U is a complete, serially controlled, drive system for unipolar stepper motors from Active Robots