Collision trigger for moving platform

Unity Engine
1

I have a moving platform that I am able to stop and restart by pressing a key. I would like to be able to collide with an object in order to stop the movement of the platform. How can I do this?

2

Not to sure what you want the outcome to be, but this should be helpful to understand how to stop something,

public float moveSpeed = 3.0f;

    void Update()
    {
        transform.position += Vector3.forward * moveSpeed * Time.deltaTime;
    }

    void OnTriggerEnter(Collider coll)
    {
        moveSpeed = 0.0f;
    }

I just threw the movement update in there to show you how to have a variable control part of your movement speed, then when it equals 0 from something going inside of the triggerzone it will stop the platform from moving.