bluetoot_arduino,ino

bluetooth_arduino.ino

#include <SoftwareSerial.h>
SoftwareSerial BTSerial(3,2); //Rx, Tx

void setup() {
  Serial.begin(9600);
  BTSerial.begin(9600);
}
void loop() { 
  if(BTSerial.available()) {
    Serial.write(BTSerial.read()); }
  if(Serial.available()) {
    BTSerial.write(Serial.read()); }
} 


#include <SoftwareSerial.h>

SoftwareSerial BTSerial(3, 2); //Rx, Tx
const int ledPin = 13;
char indata;

void setup() {
  BTSerial.begin(9600);
  pinMode(ledPin, OUTPUT);
}

void loop() { 
  if(BTSerial.available()) {
    indata = BTSerial.read();
    if(indata == 'H') 
      digitalWrite(ledPin, HIGH);
    if(indata == 'L') 
      digitalWrite(ledPin, LOW);
  }
} 

modified