Analysis of the Precision, Accuracy, and Variability of the GL5506 LDR Sensor as a Low-Cost Luxmeter

Abstract

The LDR (Light Dependent Resistor) sensor is inexpensive component that has been used as an alternative light intensity monitoring system, however its performance can be vary significantly because of large manufacturing variability. This study evaluates the performance of four GL5506 LDR sensors (S1-S4) as Arduino based luxmeter by considering lux-prediction accuracy, ADC-Signal stability, and sensor characteristic differences using a two-way ANOVA analysis. Light levels of intensity were measured from 10% to 100%, and turned the signals from the Arduino’s ADC into lux values by exponential regression model. Accuracy was evaluated using MAE, RMSE, and R². While stability, was assessed through standard deviation and the coefficient of variation (%CV). The results showed that all sensors had dominant lux-ADC relationship (R² over 0.997), but there are big differences in their actual accuracy. S1 and S2 had the lowest error, S4 is the most stable with a %CV of 0.32%, and S3 has the largest error, with an MAE of 41.92. The ANOVA results show that both the light level and the sensor unit have a big effect on the ADC values (p < 0.001), but the light error only depends on the sensor unit, not the light level (p > 0.05). These results suggest that each LDR should be calibrated on its own to get the most accurate light measurements.