I have an Ultibots D300VS delta printer (sadly no longer in production) that I use a lot.
It has a Duet Wifi control board, which has a great web interface that can do everything you need to do.
Sometimes, however, I wanted to be able to do a task at the printer, and this required using my phone to connect to the printer. There is a nice display available (PanelDue) but it was more money and functions than I need.
So I made my own. It lets me do 3 tasks that I prefer to do at the printer:
- Pre-heat the bed and extruder
- Monitor the status of a print
- Pause the print, extrude filament so I can change the color, and resume the print.