#include <SoftwareSerial.h>

#define PORT_SPEED 115200

//SoftwareSerial Serial1(10, 11); // RX | TX

void setup()
{
  pinMode(9, OUTPUT);  // this pin will pull the HC-05 pin 34 (key pin) HIGH to switch module to AT mode
  pinMode(8, OUTPUT);  // controls HC-05 ground via transistor, when HIGH, HC-05 is powered

  digitalWrite(9, HIGH);
  digitalWrite(8, HIGH);
  delay(1000);

  Serial1.begin(38400);  // HC-05 default speed in AT command more
  Serial1.write("AT+UART=");
  Serial1.write(PORT_SPEED);
  Serial1.write(",0,0\r\n");
  Serial1.flush();

  delay(1000);
  digitalWrite(9, LOW);
  digitalWrite(8, LOW);
  delay(1000);
  digitalWrite(8, HIGH);

  Serial.begin(PORT_SPEED);
  while (!Serial) {
    if (Serial1.available())
      Serial1.read();
    delay(100);
  }
  Serial1.begin(PORT_SPEED);
}

void loop()
{
  // Keep reading from HC-05 and send to Arduino Serial Monitor
  if (Serial1.available())
    Serial.write(Serial1.read());

  // Keep reading from Arduino Serial Monitor and send to HC-05
  if (Serial.available())
    Serial1.write(Serial.read());
}