Looks interesting. Very clear documentation as to what you need, how to put it together, calibrate and start using.

www.fenix-autopilot.com

This does look interesting. Good find.

Have you priced up the cost of the individual components to check if it works out cheaper than a 2nd hand tiller pilot?

I've just scanned though the doco and it looks like the control is via an app on a bluetooth connected phone? Neat idea, but the interface looks to have lots of small buttons and text - hard to see without my reading glasses and in full sun. If I build one of these I'd be looking to extend it to use an e-paper display and have physical buttons.