invisible layer / seismic logger
✕
experiment 08 · accelerometer
the ground
is never still.
Lay your phone flat on a desk or floor and watch. Every truck that drives past, every footstep in the corridor, every distant train — your phone picks it up. This is the same principle behind professional seismograph networks. Your MEMS accelerometer is sensitive to about 0.001 m/s² — enough to detect vibrations from 50 metres away.
researchers have tracked people through walls using only phone accelerometers. A study at Stanford showed that your walking gait — measured by an accelerometer — is as unique as a fingerprint. Footstep vibrations through floor and furniture can reveal which room you're in, how many people are present, and whether you're sitting or standing. No camera. No microphone. Just the ground shaking.
0.000
m/s² · current vibration magnitude
waiting
0.000session max
0events logged
0srecording
live seismograph
0s
event log
lay phone flat on a hard surface to begin
▶ how does this work?

The accelerometer in your phone is a tiny MEMS (Micro-Electro-Mechanical System) device — a microscopic spring with a proof mass, whose deflection is measured capacitively. It can detect accelerations as small as 0.01–0.1 mg (milli-g), which corresponds to about 0.0001–0.001 m/s². This is well within the range of floor vibrations from footsteps and traffic.

We remove the gravity component by high-pass filtering the signal, leaving only the vibration component. Events are logged when vibration exceeds a threshold — scaled to a rough equivalent on the micro-Richter scale for nearby events.

Try: tap the table 30cm from the phone. Slam a door in the room. Have someone walk past.