A notifier device and method of use which can be placed into an air filter for an HVAC system and which produces a whistling sound when the filter needs replacement. In an example, a method of fabricating an interconnect structure for an integrated circuit involves forming a first hardmask layer above an interlayer dielectric layer disposed above a substrate. The computer-readable code also includes code to navigate to different ones of the message parameter fields by interpreting non-compiled instructions.