Hi Gary,
Apologies for the delay .... that's a really good question regarding multiple focusers operating at the same time. I have been sketching stuff out trying to figure out how it might be best achieved, also spoken to the guys that designed the ASCOM platform to ask their advice and got some really helpful feedback (as is the norm).
The bottom line is .... it's not all that easy as I get the impression the platform was not really designed to support such a feature. However, just because it's hard and probably won't work is no reason not to do it anyway
plenty of head shaped dents in the wall disprove that !
I think the simplest solution might end up essentially a duplication of resource. So two motors and two controllers with two separate USB connections. Each controller is running the same PIC firmware but has a hardware jumper to select controller 0 or 1. You would also have to install two drivers one for each controller. Finally you invoke two client programs and select 'SharpSky 0' on one and 'SharpSky 1' on the other.
It's not ideal but I think it could be made to work.
It would be possible to use a single controller but this would obviously result in a complete hardware re-design. I don't know of a commercial product that provides dual functionality (anyone know of one ?) this maybe because there is low demand for such a feature and it would increase cost.
It is a very interesting problem ... I'll look into how much work is involved.
Cheers,
Dave