Sensor Data Sending Thru Bluetooth to Android App

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Hi! I need help on these stuff and I am planning to make a project and app out of it.

So first of, the stuff I do have are:

1x Arduino UNO

1x Bluetooth HC-05 (Keeps blinking)

1x Raindrops Sensor

2x HC-SR04 Ultrasonic Motion Sensors

Now, the question that I do have are:

  1. The bluetooth keeps blinking even I connect my Android phone in it. Should I switch it to slave or master?

  2. What mode should I have it preferred with so that I receive data from my phone app? Slave or Master?

Thanks for the advice in advance.