House ECG

Every building has its own vibration rhythm. House ECG uses the motion sensors in a dedicated iPhone to observe that rhythm over time—much like a long-term ECG for a house. Mount an iPhone 8 or newer at a fixed structural point, connect continuous power, place the screen face up, and keep House ECG open in the foreground. The app measures motion 50 times per second, establishes an initial reading for that exact installation point, and compares later stable observations with the same point. House ECG includes: - Three-direction vibration measurement, with north–south and east–west directions shown only when the phone's direction reading is reliable. - Welch spectral averaging with Hann windows and 50% overlap to reduce the influence of incidental bumps and noise. - A low-cost continuous watcher that performs fuller analysis only after a candidate vibration is detected. - Local candidate-event history and user labels for earthquake-like events, traffic, machinery, impact, device movement, or unknown events. - On-device SQLite storage for initial readings, history, and raw candidate-event waveforms. - Optional Sign in with Apple for Email notifications; basic monitoring does not require an account. - Optional comparison with the public USGS global earthquake catalog, approximate address, and weather context when an Email notification is requested. - Clear installation guidance and automatic reminders to create a new initial reading after moving, lifting, remounting, rotating, or changing floors. House ECG was conceived by a Taiwan-licensed civil engineer and National Taiwan University graduate who has participated in earthquake-related work since the 1999 Chi-Chi earthquake. The method is grounded in established vibration-analysis practice and is being improved through long-term field testing. Important: House ECG is a change-screening and field-observation tool. It is not a certified seismometer, earthquake early-warning system, structural safety certificate, or substitute for an inspection by a qualified professional. It does not declare a building safe or unsafe.