The arduino boards arrived today. The nano version in the pic is just so much smaller than the uno, yet has more or less the same functionality. Only real difference I can see is it only supplies 3.3v if running on USB power. Won't be an issue here.
The uno arrived early and I had the compass chip and the bluetooth working with it in about 15 minutes. I wrote up a small app for the PC to read headings from the bluetooth serial port, correct for mag offset, and feed the heading into poth dome. I thought I might have to store and average readings but it only seems to wobble around about .5 degree on the bench. It should work just fine.
The nano board arrived after lunch and I simply swapped boards and almost everything worked. The bluetooth seems to have a large send buffer and it was writing to it faster than I was reading. I changed the code so it would only send a heading if I requested one. All good, so off to jaycar for a box and a battery bits tomorrow.
[edit]
I see on
stargazers they use an arduino to drive an
easydriver board via ascom to control steppers for focus control. I'll have to look into that.