Reinforcements

I made the assembly a whole lot sturdy by throwing more bricks at it which helped with rigidity a bit. The potentiometer is now relatively fixed in place and the pieces do not wiggle free any more (I think). How ever, due to the fit, there still is much play left to right and thanks to the universal joint, there Is a mechanical dead zone in the middle. These are not very problematic, but I would like to try and solve those issues.

Flexible shaft test

This was a very bad idea. One weak point and a part that introduces play is the universal joint. My idea was to use a rubber Lego shaft and use that as a universal joint, stiffening it at places where it needed no flex. Well, it flexed everywhere and the the joint area alone was enough to absorb just about the entire rotary movement.

Fixing in place
    
For making the assembly a bit more rigid, I used foam to secure it. This still gives some play, but mostly it fixes it in place quite securely. Still not ideal and at this point thought for version 2 started to creep in.

Version 2

So I broke the universal joint. That is why prototyping with Lego is so nice, it shows you where the weak spots are. I fixed it with glue and tie wraps, but there are only so many bricks you can throw at the problem before a rethink is needed.

Luckily there is a simpler solution. Version 2 is going to be a direct from shaft connection that will require slight modification of some of the parts of the wheel itself.

You might have been wondering why it took this long to realise this was the more sturdy and elegant solution, but version 1 had one great advantage. It was easy to tinker with in place and it proved that concept was sound.

More details on version 2 in the next log.