Using Arduino as controller in Unity is giving me bad framerate

My framerate drops to ~15fps when u use an Arduino as my input, ~25fps when i use my keyboard as input however if i exclude Arduino completely from my game i get a solid 100+fps. My game in in 2D. Here is my code ```

public class Player : MonoBehaviour {

 public float moveSpeed = 6;
 public float gravity = -20;
 public float jumpDistance = 8;
 Vector3 moveDistance;
 byte arduinoInput;

 SerialPort stream = new SerialPort("COM7", 9600);   
 Controller2D controller;    
 void Start() {
     
     controller = GetComponent<Controller2D>();  
     //sp.DtrEnable = true;
     stream.ReadTimeout = 100;
     
     stream.Open();          
 }

 void Update() {
     

     if (stream.IsOpen) {    
         try {
             arduinoInput =  (byte) stream.ReadByte();
             print(arduinoInput);   
         }
         catch (System.Exception) {

             
         }
     }
     

     if (arduinoInput == 2) {       // Als je de 2de drukknop indrukt
         moveDistance.x = -moveSpeed;   // Ga je links bewegen
         controller.Move(moveDistance * Time.deltaTime);     // Leest de input
     }
     if (arduinoInput == 3) {       // Als je de 3de druknop indrukt
         moveDistance.x = moveSpeed;     // Ga je rechts bewegen
         controller.Move(moveDistance * Time.deltaTime);     // Leest de input
     }


     if (controller.collisions.above || controller.collisions.below ) {   
         moveDistance.y = 0;
     }
     if ((Input.GetKeyDown(KeyCode.Space) || arduinoInput == 1) && controller.collisions.below) {   
         moveDistance.y = jumpDistance;  // Je gaat springen langs de y-as
         //moveDistance.x = 0;     
     }

     Vector2 input = new Vector2(Input.GetAxisRaw("Horizontal"), Input.GetAxisRaw("Vertical")); 
     moveDistance.x = input.x * moveSpeed;   
     moveDistance.y += gravity * Time.deltaTime;     
     controller.Move(moveDistance * Time.deltaTime);            
 }

 

} ```

Would appreciate if anyone could identify this problem