Digital Finder interfacing for Dobsonian & other visual scopes

[AstroKeith]

I'm seeking feedback on a draft interface specification.

I've been working on digital finders for a couple of years now. I'm finally pretty happy with my own and it is being copied by quite a few. Many others have made their own home-brew versions. Link to mine https://astrokeith.com/equipment/efinder/

The digital finder has many applications, from simple 'push-to' to fully integrated with a drive system. I'm interested in the integrated end. I've made a ScopeDog mk3 that has the digital finder completely integrated and utilises the same processor as the drive. I'm experimenting with a mk4 that dispenses with the optical encoders completely.

I am in conversation with two suppliers who are developing Dobsonian drives (ie a ServoCat replacement). Both are including a spare port to allow a digital finder to be added.

The attached document aims to help them provide the necessary interface from their side. It includes a functional description to put it into context.

Comments welcome, especially from those who have also dabbled in the digital finder. The current document is of course very much aligned to my own work, so it needs wider validation