Here's an Easy way to get along with the Bluetooth connected Arduino controlled by the Android device /Any mobile device /Internal serial monitor

Step 1: Connecting the Module (HC-05)

First make sure that your Arduino uno Board is working.
After checking the Board , now it's time to connect the Bluetooth module to the Arduino uno board

Step 2: Connection Configuration

You will find the 6 pins in the Bluetooth module
But it's enough to connect the 4 pins to work with the module ( leaving EN pin and STATE pin)
Connect the RX pin of module to TX (pin 1) from Arduino board
Connect the TX pin of module to RX (pin 0) from Arduino board
Connect the VCC pin of module to 3.3v pin in Arduino board
Connect the GND pin of module to GND pin in Arduino board

Step 3: C Program With Serial Window

The program in the image is to make yourself comfortable with working the Arduino board using the module to activate the led via entering 'a' and to deactivate via entering 'b' in the serial monitor/terminal software in android mobile

Basic Logic in the program
After uploading the program to the board with the respective connection

Open the serial window and enter 'a' to turn on the Pin 13 Led and enter 'b' to turn off the Led

Can be done in serial monitor or s2 terminal software

Step 4: Work With Terminal

To work via Serial monitor :
click the serial monitor an change the baud rate to 9600 and then start working with the monitor
To work via Terminal wireless using Android mobile :
Download the terminal software called S2 terminal for Bluetooth and do the following steps as in the image above
Connect the Bluetooth module with the mobile and then the module will have a light delay of 2 seconds to indicate that the module and the mobile has been connected /paired
Now you can enter the letters and check the working
You can modify it according to your wish ..…