Mobile-phone accelerometer comparison (2026): four Samsung phones for standstill micromotion

A controlled cross-device consistency test of the accelerometers in four Samsung phones (Galaxy A52s 5G, S21, S23 Ultra, S26 Ultra), logged with Physics Toolbox Sensor Suite at a nominal 10 Hz. Two recordings per phone: Still on the floor with triple-clap sync markers - the sensor noise floor Exercises -> standstill -> shaking - working range and saturation. Purpose: quantify how comparable these phones are as micromotion/standstill sensors, so data recorded with different phones can be normalised in future. Findings: ~1.9x spread in noise floor (A52 quietest 10.4 mm/s^2 -> S23 -> S26 -> S21 loudest 19.9; S21 noisiest, matching the field artifact direction); no clipping in any device; device noise (~1-2 mm/s QoM) sits below the ~6.5 mm/s human head-micromotion signal. Includes GPS-stripped raw logs, per-device summary + figures, the analysis code, and non-identifying device/firmware metadata. Device screenshots (serial number/IMEI/phone number) and GPS data are withheld for privacy.