void SW_state(){
   //0-boot mode 
   //1-test mode don't know
   if (cnt-4<=0){
    SWstate=0;
   packet+=String(SWstate);
   packet+="\r";
   }

   else{

    int p1=bmp.readPressure();
    int p2=bmp.readPressure();
    int p3=bmp.readPressure();

    int a1=bmp.readAltitude(1013.25)-calibration;
    int a2=bmp.readAltitude(1013.25)-calibration;
    int a3=bmp.readAltitude(1013.25)-calibration;

    if (p1%10==p2%10 && p2%10==p3%10 && a1==a2 && a2==a3){
      SWstate=2; //launch pad
    }

    else if (p2%10<p1%10 && p3%10<p2%10 && a2>a1 && a3>a2){
      SWstate=3; //Ascent
      
      if (a1>800 && a1<=900 && a3<a1 && p3%10>p1%10 ){
        //camera should start recording here
      SWstate=4; //Deployment
    }
    }
    
     else if (p2%10>p1%10 && p3%10>p2%10 && a2<a1 && a3<a2 ){
      SWstate=5; //Descent
      if (a3>=500){
      s.write(180); //servo turns to deploy second parachute
      SWstate=6; //Aerobreak Release
      if (p1%10==p2%10 && p2%10==p3%10 && a1==a2 && a2==a3){
        SWstate=7; //Impact
        //buzzer should switch on here
      }
    }
    }

   packet+=String(SWstate);
   packet+=">\r";

   }
}