react-native-android-btserial as described in its readme is
"A react native android module for serial IO over bluetooth device."
This module is perfect for an android app connected to an arduino in a simple way. Because BlueTooth is not popular nowadays, there are not many modules for react native that can be used in a recent version of RN, so a search a lot and then fix this one.
I fixed the compatibility of this package for react native >= 0.47 so it can be used in newer projects.
This is the pull request
https://github.com/derektu/react-native-android-btserial/pull/4
And here is a screenshot of me logged in
