A frontier proposal with a validation plan, not an implemented detector.
Intended capability
Research whether the field could support this proposed outcome: Trends air-filter loading from the register: as filters load, airflow drops and vent-flutter band signatures shift — replacing calendar-based filter changes with condition-based ones.
This describes the intended outcome. Readiness is research concept, evidence is class C, and a catalog mapping or recording is not proof of this outcome at a real site.
Solution blueprint
See the environment before installing it.
This exact kit is one of 191 first-class designs. It includes geometry, objects, nodes, wording, scenarios, installation, limitations, and catalog-bound readiness.
No rendered revision is available yet.
Bundled recording
A related Buildings scene
This is one recorded vertical scenario. It is not separate validation of every capability in the catalog.
01 The physics
Vent grille and duct-walls flutter at airflow-dependent frequencies (5-40Hz, the proven airpath observable); loading filters reduce flow, shifting flutter center-frequency and energy monotonically. A slow drift observable, ideal for CUSUM statistics.
02 Shared processing path
Edge Doppler summary on register-adjacent links -> flutter-line center + energy per HVAC-on cycle (cycle gating from the machine band) -> CUSUM drift vs post-change baseline -> filter-loading index with change recommendation.
This is a capability design path. Components may be shared with other catalog entries; it is not presented as a unique algorithm.
03 Validation plan
Own-hardware on two systems across one full filter lifecycle each vs differential-pressure sensor ground truth; report correlation of the index vs delta-P and detection of the artificial 50%-blocked test.
04 Commercial hypothesis
For facilities/home: 'Change filters when the airflow says so, not when the calendar does.'