Your error message is pointing you to line 37. I can’t tell which line that is because you haven’t used code tags to share your code with proper formatting: Using code tags properly - Unity Forum
Most likely you don’t have an ObiEmitter component on the same GameObject as this script, meaning GetComponent() will return null, which causes the NullReferenceException when you try to access it in Update(). GetComponent only gets components from the GameObject you call it from. When you call it inside a MonoBehaviour like that, that means the same GameObject that your MonoBehaviour script is attached to.