This Android app provides a line-oriented terminal / console for devices with a serial / UART interface connected with a USB-to-serial-converter.
It supports USB to serial converters based on
- FTDI FT232, FT2232, ...
 - Prolific PL2303
 - Silabs CP2102, CP2105, ...
 - Qinheng CH340, CH341
 
and devices implementing the USB CDC protocol like
- Arduino using ATmega32U4
 - Digispark using V-USB software USB
 - BBC micro:bit using ARM mbed DAPLink firmware
 
- permission handling on device connection
 - foreground service to buffer receive data while the app is rotating, in background, ...
 
The app uses the usb-serial-for-android library.
I got various requests asking for help with Android development or source code for my Serial USB Terminal app. Here you find a simplified version of my app.