Use APKPure App
Get SerialBluetooth Arduino old version APK for Android
Demo app to connect to Arduino through Bluetooth Serial profile
Simple application to test your arduino Bluetooth serial module
This application sets up a bluetooth serial connection to another device to send and receive data.
It has been built as a proof of concept to test a basic Arduino Bluetooth module.
A tutorial in Spanish can be found at: http://www.manualsupervivenciamaker.com/manual/bluetooth_y_conexiones_moviles.html