Sure thing Hy-Fye1.

Current status on this driver is a bit up in the air while I get around my use of too many "cheapduinos" at once via head scratching and udev rules.
Overall the version at the above github link was working with the Xagyl filter wheel when plugged by itself at my desk pc. I got around the magnet placement and the fix should work for any wheel now. This version is for the cheap little 5v gearhead byj motors with ULN2003 driver boards you can get at ebay or Amazon. after removing the screw, I drilled and tapped mount holes in one cover for the motor, then glued the motor into the threaded hole left by the screw by filling it with epoxy from the other side then screwing the screw back in a bit with the motor in place. Be careful you don't let glued into the motor. I used a bit of tape on it and then just left it in there. The motor runs in unipolar mode. Just plug the motor connector into board and install with a header or wires to the pins on the Arduino. The magnet placement isn't critical but make sure when you mount the hall effect that the board will clear filters and magnet. Placing the magnet anywhere between 4 and 0 (5 and 1) does the trick. The rest is just a process of figuring out steps by trial and error, change and download, until each filter lines up. since they all reference from a known home position the filter positions will be increased by about the amount of of the distance of the first one to the second so after that point things go a bit faster. The distance from the home position sets filter 1. I plan to get the offsets in the indi xagyl driver to actually work at some point which will be great for fine tuning position but right now that part as well as much of the info screen is just placeholders.
Rather than go reverse to get to lower numbers, I chose to eliminate lash issues by having the motor only run one way as much as possible. a lower value (i.e. from 4 to 2) will make the wheel run on around and find home, then run to the stored value of the filter requested. The wheel self calibrates any time it passes home or goes to a filter of a lower position value.
Once on the mount in mixed skies, mine is currently telling me filter_0 not defined and other great errors...I think I've been trying to change the color of my focuser.