Unity3d Timer

Coroutine.cs

 IEnumerator Start() {
     while(true) {
         yield return new WaitForSeconds(1f);
         OutputTime();
     }
 }
 void OutputTime() {
     Debug.Log(Time.time);
 }

InvokeRepeating.cs

 void Start () {
     InvokeRepeating("OutputTime", 1f, 1f);  //1s delay, repeat every 1s
 }
 void OutputTime() {
     Debug.Log(Time.time);
 }

Update.cs

 float elapsed = 0f;
 void Update() {
     elapsed += Time.deltaTime;
     if (elapsed >= 1f) {
         elapsed = elapsed % 1f;
         OutputTime();
     }
 }
 void OutputTime() {
     Debug.Log(Time.time);
 }

https://answers.unity.com/questions/1220440/how-to-display-call-a-function-every-second.html