     delay(100);
     abort();
   }
+  
+  // if the automatic anchor calibration is unsuccessful, try manually setting the anchor coordinates.
+  // fot this, you must update the arrays anchors_x, anchors_y and heights above
+  // comment out the doAnchorCalibration block and the if-statement above if you are using manual mode
+  //SetAnchorsManual();
 
   printCalibrationResult();
   delay(3000);

  // clear all previous devices in the device list
  Pozyx.clearDevices();
     
  int status = Pozyx.doAnchorCalibration(POZYX_2D, 10, num_anchors, anchors, heights);
  // if the automatic anchor calibration is unsuccessful, try manually setting the anchor coordinates
  // fot this, you must update the SetAnchorsManual function below
  // comment out the doAnchorCalibration if you are using manual mode
  //SetAnchorsManual();
  
  if (status != POZYX_SUCCESS){
    Serial.println(status);
    Serial.println(F("ERROR: calibration"));

  }    
}

// function to manually set the anchor coordinates
void SetAnchorsManual(){
 
 int i=0;
 for(i=0; i<num_anchors; i++){
