holopy3/Assets/Scripts/BounceUpAndDown.cs

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

public class BounceUpAndDown : MonoBehaviour
{
    public float yMin = 0.9f;
    public float yMax = 1.2f;
    private bool goingDown;
    private bool bounce = false;

    private void OnEnable()
    {
        PassTheEdgeTrigger.OnPassingTheEdge += StartBouncing;
    }

    private void OnDisable()
    {
        PassTheEdgeTrigger.OnPassingTheEdge -= StartBouncing;
    }


    void Start()
    {
        goingDown = true;
    }

    void Update()
    {
        if (bounce)
        {
            if (goingDown && transform.position.y > yMin)
            {
                transform.Translate(Vector3.down * Time.deltaTime, Space.World);
            }
            if (transform.position.y <= yMin)
            {
                goingDown = false;
            }
            if (!goingDown && transform.position.y < yMax)
            {
                transform.Translate(Vector3.up * Time.deltaTime, Space.World);
            }
            if (transform.position.y >= yMax)
            {
                goingDown = true;
            }
        }
    }

    private void StartBouncing()
    {
        bounce = true;
    }
}