Camera Brightness

The Phyphox app has a Brightness experiment and a real-time FFT of the brightness. Changing brightness occurs at edges of vibrating objects, so this can be used as another non-contact sensing method. The big benefit of this measurement compared to others is its higher sample rate. It uses a 240 frame-per-second sample rate, so up to 120Hz vibrations can be detected. 

Credit to Daniel Duyvestein for discovering this during a Winter 2026 structural dynamics lab!