I have a project that involves sending messages from an Android device to an Arduino using a bluetooth module. I am using an HC-05 bluetooth module and an Arduino Mega 2560.
It works as long as I power the Arduino to my laptop using a USB cable. However, I need to use an external power source and have been using a 6F22 9V battery connected through the VIN pin for this purpose, without facing any problems. But on connecting the HC-05, it does not even light up.
The Arduino is also connected to four dc motors, five servo motors (all of which are externally powered, only get digital signals from the Arduino), and seven HC-SR04 ultrasound sensors, whcih are powered through the 5V pin.
I have connected the HC-05 to the Arduino as follows:
RX TX through a voltage divider
I am new to all this, and would be grateful for any help. Thank you.