Extend time by picking up object problem

I am playing with Unity’s Catch Game tutorial, and trying to add an object that would extend time when picked up. I added a timer like this in fixed update:

void FixedUpdate(){
	if (playing) {
		timeLeft -= Time.deltaTime;
		if (timeLeft < 0) {
			timeLeft = 0;
		}
		UpdateText ();	
	}

}

and then i did this:

void OnCollisionEnter2D(Collision2D collision){
	if (collision.gameObject.tag == "timer") {
		timeLeft += 10;
	}
 }

I also tried with void Update(), but id did not work. Thanks in advance.

Main thing I see here is that you don’t call UpdateText() after adding the time (though this still should show after the next FixedUpdate).
Are you sure you are checking for the tag exactly? Is there a capital T maybe?

Try putting a Debug.Log("Time Added") after timeLeft += 10; to see if the collision tag is “timer”, and a Debug.Log(collision.gameObject.tag); outside the if statement to check an actual collision happened.