void OnMouseDown() //if the cube is clicked { if (!yellow) { Debug.Log("Turn on LED!"); rend.material.SetColor("_Color", Color.yellow); //turn the cube YELLOW arduinoConnector.WriteByteToArduino(255); //send 255 to Arduino yellow = true; } else { Debug.Log("Turn LED off!"); rend.material.SetColor("_Color", Color.blue); //turn the cube YELLOW arduinoConnector.WriteByteToArduino(255); //send 255 to Arduino yellow = false; } }