Well I did actually do a few things today – I finished an abandoned mount for a secondary scope – I had been thinking of it as a potential finder, but it lacks the field of view, but it seems a good candidate for a guide scope. The basic thing is two circles of plastic, each with two adjusting screws and a 'sprung' plastic plug/piston, joined by an aluminium bar that fits on one of the scope rings. There are several degrees of adjustment, the idea being you can find a suitably bright 'guide star' then a webcam and some clever software sends signals to adjust the tracking of the mount.
This means making a declination access drive to complement the RA drive – I've found a suitable stepper and gear train, yesterday I made a fitting for the final gear out of stainless. Due to space constraints an cross-pin for the final drive gear was impractical so I was quite please with my solution – a special nut like a thick washer, with two 1/16" pegs that engage in the slots in the gear Not too simple as the nut is M6 and the gear is 8mm bore so everything needed to be more or less spot-on. Finally locked with a neat M6 acorn nut (I love finding I've saved the right bit – just like finding two springs just right for the guide scope rings!)
Still need to make a bracket for the stepper – this one will also need two intermediate gears instead of 3, as there is much less space, even after shifting the RA drive down a bit – about 1/8" clearance!
If all this burst of activity isn't enough, turned a 1.250" hole in a no-longer-needed temporary pulley and epoxied a length of aluminium tube it. This will be finished off with either an M42 or a T-mount thread so I can use it with a canon adaptor for using a camera with my smaller scope – that hasn't got a built in t-adaptor.
Of course the real challenge will be making the drive electronics, but I've found one of my early computer experiments with a green 64×128 display, an interface for an Amstrad emailer keyboard and lots of I/O that should be able to do the job.. Brilliant things microprocessor projects – you can turn them into something completely different!