controlling a stepper with a simple trigger switch

[Gary]

Gary, does the uim243 have an inhibit/limit input? if not then wont do what OP needs as he wants a parking feature too.

I'd use an Arduino with a stepper driver shield, its quick, cheap and easily adaptable.

Phill05 - pm me if you want some help on this.

This UIM243 is a very simply and easy to use product.
It is a stepper driver that has a pulse generator built in and can either have an external 0-5V speed reference or use an inbuilt in pot for the speed.

It has an enable and run input.
you can use the run or the enable in conjunction with limits, but a park feature would need a bit more logic behind it.