Peter, The box with the built-in ST-4 control and engagement clutch looks interesting, but I fear it's non-adjustable speed will limit it's appication with an equatorial platform unless you can "hack" it somehow. A fresh accumulation of 15 inches of snow here in Minnesota will only serve to delay my outdoors testing of things, but before it snowed I did make some progress. My 2 feet by 4 feet plywood for the top and bottom of my platform was enough for THREE platforms, so that is exactly what I made while I was in the garage, anyway. I plan to give one to a friend and I'm not sure about the 3rd one yet. Each one had a bad solder joint or two, but now the electronics all seems to be working. I changed the value of one resistor and one potentiometer in the end to have more adjustment in my "fine tune" for motor speed. Any design flaw that exists in one is shared by the others! Sorry if I am polluting this thread about a simple VNS platform with all my pictures of a setup that is a bit more complicated, but since I got all my inspiration from this thread, it seemed like the place to respond. I currently have made my VNS segments using the templates provided by Reiner Vogel, but it is possible I will be changing them out for some made using my own calculations. For those of you with intestinal fortitude, I have attempted to attach a long-winded document (17 pages??) that I put together documenting the time I have perhaps squandered with calculating VNS segments in recent weeks. It was not written with Microsoft WORD, so the formatting may be awkward when you open it, but perhaps buried in those pages is a useful idea for someone... or not 😉Calculating curves for segments.doc