TeenAstro Mini successful assembly
I kindly got PCBs from Charles and have soldered the parts together for a TeenAstro Mini you can see below.
I built the software from source from github and can communicate via LX200. So far a full success.
I intend to build a hand controller too, but I have still to wait for the ESP and the display ordered in China.
There are now a few questions left on how to configure for motors and motor controllers and so on. I will address that in a separate message...
One thing I would suggest for the BOM is to change the clock crystal for the Teensy to one in a TC26 case (like https://www.reichelt.de/mini-uhrenquarz-0-032768-mhz-tc26-0-032768-l6-p32847.html?&nbc=1) instead of the tiny surface mount model, which is difficult to handle, especially for people not very experienced in SMT parts handling. The Teensy 3.2 board seems to be designed for the TC26 case crystal and certainly not for an SMT one.
A big thank you to all the people who worked on the TeenAstro and the OnStep projects and made it freely available.