Dos & Don’ts in Measuring Illuminance With Smartphones

We explored the reliability of smartphones for measuring illuminance and discussed their use on occupational lighting assessments. In a 20–1000 lux range, we compared the illuminance readings from three Android applications on two smartphones versus a calibrated illuminance meter, and proposed seven calibration criteria. Mean non-calibrated smartphone measurements ranged between 28.36% and 37.58% above the reference illuminance. Two calibration criteria stood out: (i) single correction factor at the mean illuminance level (relative difference = 0.84%); (ii) power function (relative difference = −0.17%). We can state that properly calibrated smartphones might replace a low-end illuminance meter, and provide practical tips for measuring illuminance with smartphones.