void SW_state() {
  //0-boot mode
  //1-test mode don't know

  int p1 = pressure[0] / 100;
  int p2 = pressure[1] / 100;
  int p3 = pressure[2] / 100;

  int a1 = altitudes[0];
  int a2 = altitudes[1];
  int a3 = altitudes[2];

  //    if (p1==p2 && p2==p3 && a1==a2 && a2==a3)

  //   else if (a1<=5.0 && a2<=5.0 && a3<=5.0){
  if ( (SWstate == 0 || SWstate == 2) && a1 <= 5 && a2 <= 5 && a3 <= 5) {
    SWstate = 2; //launch pad
  }

  else if ((SWstate == 2 || SWstate == 3) && p2 < p1 && p3 < p2 && a2 > a1 && a3 > a2 && a1 > 5 && a2 > 5 && a3 > 5) {
    if (millis() - start_BLDC >= 7210 || a1 > 800 && a1 <= 900 && a3 < a1 && p3 > p1) {
      //camera should start recording here
      ON_camera();
      BLDC.write(80);
      SWstate = 4; //Deployment
    }
    else {
      SWstate = 3; //Ascent
    }
  }

  else if ((SWstate == 4 || SWstate == 5) && p2 > p1 && p3 > p2 && a2 < a1 && a3 < a2 && a1 < 800 && a2 < 800 && a3 < 800 ) {
    if (SWstate == 5 && a3 <= 500) {
      s.write(180); //servo turns to deploy second parachute
      SWstate = 6; //Aerobreak Release
    }
    else {
      SWstate = 5; //Descent
    }
  }

  else if (SWstate == 6) {
    if (a1 < 5 && a2 < 5 && a3 < 5 && p1 == p2 && p2 == p3 && a1 == a2 && a2 == a3) {
      BLDC.write(0);
      SWstate = 7; //Impact
      OFF_camera(); //camera stops recording here
      //buzzer should switch on here
    }
    else {
      SWstate = 6;
    }

  }

  else {
    SWstate = 0;
  }

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

}