Adding a slider

So, currently my game responds to the input from a sensor. Different levels of force exerted on the sensor refer to different colours. I now want to add a slider that indicates the level of force that is being exerted on the sensor. I have added a slider but am not sure how to link it to the initial script.

This is the initial script:
using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using System.IO.Ports;
using System.IO;
public class arduino : MonoBehaviour
{

    public SerialPort sp = new SerialPort("\\\\.\\COM5", 9600);// Com port and the baud rate of the arduino
    Material m_Material;
    GameObject Sphere;



    void Awake()
    {
        Sphere = GameObject.FindWithTag("Player");
        m_Material = GameObject.FindWithTag("Player").GetComponent<Renderer>().material;
    }
    void Start()
    {
        if (!sp.IsOpen)
        {
            sp.Open(); // Open 
        }
        sp.ReadTimeout = 250; // Timeout for reading 
        
    }

    // Update is called once per frame
    void Update()
    {
        if (sp.IsOpen)
        { // Check to see if the serial port is open 
            try
            {

                //string portreading = sp.ReadLine(); // get the string output of the serial port 
                //float amount = int.Parse(portreading);
                string value = sp.ReadTo("EOL"); //Read the information
                float amount = float.Parse(value);


                if ((amount > 251f))
                {
                    m_Material.color = Color.red;
                    Renderer _rend = Sphere.GetComponent<Renderer>();
                    Sphere.GetComponent<Renderer>().material = _rend.material;
                    _rend.material.mainTexture = Resources.Load("face1") as Texture;
                    Sphere.transform.localScale = new Vector3( 2f, 0.03f*amount, 2f);
                    //Sphere.transform.position = new Vector3(2f, 2f , 2f);
                }
                else
                {
                    m_Material.color = Color.white;
                    Sphere.transform.localScale = new Vector3(2f, 10f, 8f);
                    
                }
            }
            catch (System.Exception)
            {

            }
        }
    }
}

This is the generic slider script:

using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using UnityEngine.UI;

public class Force_bar : MonoBehaviour
{
    public Slider Force;
	// Use this for initialization
	void Start ()
    {
        Force.value = 300f;
	}
	
	// Update is called once per frame
	void Update () {
		
	}
}

Hi, so if I undestand it correctly you want the slider as a visual reference of the “amount” variable of your script. You can make a reference to your slider in the initial script and on your update you can do something like: yourSlider.value = amount / maxAmount;
You will need to asign a maximun amount so you can give the slider a number between 0 and 1that represents the porcentage of the maximum force that your sensor can get.
Hope it helps.

Is this a real life sensor or just a gameobject with a script?

Anyway provided it is a Canvas ui slider try this @Grey_Wolf9 :

using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using UnityEngine.UI;

public class SliderUpdate : MonoBehaviour {

    //Reference to your slider set in inspector
    public Slider MySlider;

    //This is the input value from your sensor
    public float SensorValue;
	
	// Update is called once per frame
	void Update () {

        //Set slider's value to the sensor float
        MySlider.value = SensorValue;
	}
}