and are you doing straight or curved rod design Jethro?
My advice is curved rod. Bit more work to bend it and get the curve right, but it was easier for me to do that than try and code for the speed increase that will be required over time on a straight rod design.
with the curved rod, we can program it to just do 1 rotation per minute. (provided your gears are 1:1 ratio. if its different we just speed up or slow the stepper down which is a simple case of changing one value in the code).
I'll go home and have a play as I have all the parts you have purchased. I'll write something to get the stepper going 1 rpm so all you have to do is upload it if you like. (If you want the learning experience then by all means go for it).
Also with those CH340G arduino boards (their chinese clones of the original arduino) you will need the CH340G USB driver for your version of windows. Otherwise windows will not detect it when you plug it in.
What version windows do you have? I can find the download site, as their normally in chinese. A quick google search for "Arduino ch340g driver" will probably get you in the right place also.
