I have a Motorola Z-Force Android phone and it supports communication to my Celestron NextStar+ Hand Controller with USB communications port. I tested this by sending RS-232 commands to my telescope HC with a terminal app on my Android and it even received expected acknowledgements back from the HC. It recognizes the HC's built in Prolific USB to Serial adapter without additional software. Most Android Phones can use the USB charging port as a host port with a commonly found adapter. It would be nice to be able to use SkySafari using this built in functionality rather than buying an expensive WiFi or Bluetooth adapter. It seems to me the app just needs to be able to add the ability to add the option look for the Prolific device when it it plugged directly into the Android host port to the the HC. All you need is a $10-15 adapter and a Mini USB cable to get this going, but there is no option in the SkySafari app to look for this port. Has anyone been able to get around this?
This is what I used for my USB-C device: https://www.amazon.com/Anker-Adapter-Converts-Technology-Compatible/dp/B01COOQIKU/ref=sr_1_fkmr1_2?ie=UTF8&qid=1503612707&sr=8-2-fkmr1&keywords=usb-c+to+usb+host+adapter+anker
or this for the Micro-USB devices:
https://www.amazon.com/Cable-Matters-Micro-USB-Adapter-6-Inch/dp/B00GM0OZ4O/ref=pd_sim_107_25?_encoding=UTF8&psc=1&refRID=00S5AQP651A3JKJEE84T
