hello jonathan
i am using stepper motors from nanotec.de. it's an L5618 actuator: (Nanotec - Intelligente Antriebslösungen)
it costs about 80 euro. they have also encoders for the motors.
the motor driver i am using is the smc-11:
it costs about 30 euro. it can be controlled by a pulse from 0 to 200 khz via a digital port of the arduino board.
i had some major problems generating a fast enough pulse. it worked great when i only generated the pulse without doing anything else. but reading ports and sending serial data slowed the pulse down.
right now i am using an arduino board just for generating the pulse and sending digital 1/0 (direction) to a wiring board that reads a pressure sensor and sends the data to the computer. i hope i can use only one moto and a kind of pulse generator later.
greetings
michael