Weird issue with bluetooth and serial read

Hello, I am new to this forum. (Joined cause i can't find anything like mine problem).

I am making school project with arduino and bluetooth HC-06.

Before 7 days I connected BT to arduino and everything worked fine. Then I made 7 days pause and now when I connect BT I do not recieve anything on

I tried different baud rates, checked RX and TX pins many times ( connected Rx of bt on 1 of arduino and Tx of BT on 0 of Arduino). Also restarted phone and arduino several times, BT is connected with jumpwires on board.

When I send data from app (used some default app on playstore), TX led on Arduino blinks, but i do not recieve anything on Serial.printl() (used that as a check if everything works fine)

Then I tried some example code.

#define ledPin 7
int state = 0;
void setup() {
  pinMode(ledPin, OUTPUT);
  digitalWrite(ledPin, LOW);
  Serial.begin(38400); // Default communication rate of the Bluetooth module
void loop() {
  if(Serial.available() > 0){ // Checks whether data is comming from the serial port
    state =; // Reads the data from the serial port
 if (state == '0') {
  digitalWrite(ledPin, LOW); // Turn LED OFF
  Serial.println("LED: OFF"); // Send back, to the phone, the String "LED: ON"
  state = 0;
 else if (state == '1') {
  digitalWrite(ledPin, HIGH);
  Serial.println("LED: ON");;
  state = 0;

and still same problem, TX on arduino blinks ( it is only one blink when I click send), but I do not get "LED:ON/OFF" message on serial monitor. ( I do not have diode to check, I used this code from net just to test with Serial.println).

UPDATE: this morning i turned on and it worked (do not know why)..

But there is another issue. Everything worked fine until i put my spider robot (12 servo motors and Adafruit 16-Channel 12-bit PWM/Servo Driver) and DFPlayer Mini in the circuit.

First it executed command countless times and then it stopped to work again. This is what i get on serial monitor. img tag is not working so here is link to screenshot.. Screenshot by Lightshot

Does anyone have solution? PS. is mistake that I put arduino 5v and gnd into breadboard, and BT, servo driver and dfplayer mini into those 5v and gnd columns, or I need to have another source of power?

You do indeed need another source of power.

Is 9V battery enough for all 3 together (do I need to make voltage divider or i can put raw 9v battery in breadboard), and do you think that bluetooth act weird because that?

Check on the voltage and current requirements for your servos. 6V is common and a rule of thumb for servos is 1A each, but read up on your particular servos to be sure.

9V is likely not suitable therefore, even less so if you're talking about the batteries that power a smoke detector - they can't provide anywhere near enough current.

Here is the way i wired everything.
First, sorry for clumsy sketch, this is my first work in fritzing.

Few notes:

a) Servo driver actually gets his power source from socket. I took my old 5V phone charger adapter and soldered + and - wires to driver.

b) There are 12 servo motors in driver on pins 0,1,2,4,5,6,8,9,10,12,13,14 but i didn’t draw them, to make sketch more transparent

Did I do good job or I can improve this?
Also, can I use Arduino (on sketch marked with black circle and number 1), or I need another power supply?