Real Time, Portable and Low-Cost Ultraviolet (UV) Sensor: Measuring the Solar UV Index for Sunbathing Safety

The phenomenon of sunbathing in the morning is almost ubiquitous in residential areas across Indonesia, following the "New Normal" after the Covid-19 pandemic. The local government even encourages its citizens to engage in regular 15-minute sunbathing sessions. This practice aims to stimulate the body’s production of vitamin D, thereby boosting the immune system to fight infections. However, sunbathing under a UV index above five can be detrimental to skin health, leading to conditions such as erythema, photoaging, and skin cancer. Consequently, a real-time, portable, and low-cost ultraviolet sensor has been developed to measure ultraviolet intensity (mW/cm
²
) and convert it into a UV index. The calibration process is performed by comparing the detector’s data with the UV index information obtained from Accuweather.com at the detector’s location. The UV detector utilizes the GUVA-S12SD to measure solar UV intensity and derive the UV-index value. The inclusion of a real-time clock enables the detector to function in real-time, while the keypad and TFT LCD ensure user-friendly operation and wider accessibility within the community. To facilitate further analysis, a 4 Gb SD-Card is employed for data storage. The optimized UV detector exhibits exceptional performance within an operational range of 0 to 2.88 mW/cm
²
, which corresponds to UV-index values ranging from 0 to 11. Furthermore, the detector demonstrates a remarkable sensitivity of 0.005 V/UV index. Notably, the UV detector’s accuracy and repeatability are exceptionally high, with a UVI value of ± 0.97 and a UVI value of 0.25%, respectively.