Bluetooth Control Multitap

 
#include <SoftwareSerial.h>    
SoftwareSerial BTSerial(5, 6); 
 
int relay = 9;
 
 
void setup() {
  BTSerial.begin(9600); 
  pinMode(sw, OUTPUT); 
}
 
void loop() {
  if(BTSerial.available())        
  {
    char bt;                    
    bt = BTSerial.read();        
    if(bt == 'a')                
      digitalWrite(sw, HIGH); 
    if(bt == 'b')
      digitalWrite(sw, LOW);
    
  }
}