Many applications in the modelrailraod require a very slow turning motor.
For that purpose there are a few options but mostly pretty expensive, which
is not the fact with the 28BYJ-48 stepper motor, famous from many applications in Arduino world.
This motor is ususally delivered together with a small driver module.
To control this, an Arduino-nano or higher is used.
This GCA198 board avoids the use of these boards and also supply, because it connects to standard transformer with 8-16V dc output.
Dc supply 10-16V is also possible.
All that is necessary is on-board, like regulator(s) for 5V, the output driver chip, trimmer P1 to control speed and
P2 for setting the interval time.
Addional dip-switches for setting running direction and half/full steps.
It makes a much more compact installation possible.
The motor 28BYJ-48 itself, together with the integral gearbox, is making 4096 steps for one turn.
This will very much restrict a high speed, because of each step should be more than 1200 mSec.,
but for very low speeds , this unit is perfect.
The processor on board is a cheap PIC16F688 with a very simple basic program.
This program is written with the use of PICsimulator IDE from www.oshonsoft.com .
The on board led shows when motor is running.
The trimmers can also been replaced by a 3-pin PSS 254 connector, which then
connects to front mounted potmeters on your switch board.
Other stepper motors van also be used, the best results come with single phase motors (5 wire connection).
The stepper motor has its own power regulator (VR1), so stepper motors with other voltage are also optinal,
just by selecting the right regulator for VR1.
Even supplying the motor without VR1 is possible, as long as the powersupply to the board matches the stepper motor voltage,
But power supply to the board should be minimal 9V dc or 7 V ac.