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Window-Line Drone Sentinel
A drone hovering outside the window is too faint for the indoor signal — physics says no.
We publish what we will not claim — that is how you can trust the rest.
Why the physics says no
A small plastic drone a few meters outside the house barely touches the signals indoors; its disturbance is smaller than the everyday noise. Its spinning blades also flicker far too fast for household WiFi to read reliably. We tested the idea against the physics and retired it honestly.
In the physics: A hovering quadrotor presents two observables: rotor blades produce periodic 'blade flash' modulation that aliases into the measurable 10-40 Hz Doppler band as a comb-like spectral signature unlike any biological mover, and the plastic-and-battery airframe adds a small persistent scatterer at window height where the RTI prior says nothing should float. Glass is nearly RF-transparent at 2.4/5 GHz.
Reviewer's verdict: Blade-flash micro-Doppler is real radar physics, but a small plastic quadrotor 1-5 m outside sits outside the mesh sensing volume with tiny RCS, and rotor rates (~100-200 Hz) alias unpredictably at commodity CSI rates. Its perturbation to indoor links is below the noise floor.