An ultraviolet measuring and UV index calculating system, with multiple alarm capabilities, using FPGAs and VHDL

Abstract: A novel ultraviolet measuring system, which uses FPGAs and VHDL, is presented here. The system moni- tors UV radiation of a light source or sun using GUVA-S12SD sensor connected to DE10-Lite FPGA board and after A/D conversion presents input voltage values in seven-segment displays. Calculated UV index values are also dis- played. Five external LEDs, green, blue, white, yellow and red light up depending on UV index values range, with green one corresponding to 0-2 value and red one to values equal or greater than 10.5. The above LEDs unit acts both as indicating and also alarm system presenting UV index ranging and is in parallel operation with 10 board LEDs from which left half lights up for UV index values lower than 5.5 and right half in case that UV index exceeds value of 5.5. Time process starts operating in case that UV index is above zero and switch SW0 is ON. Depending on specific UV index a critical UV exposure time value, different for respective UV index ranges, is set by programmer. The above exposure time value must not be exceeded because there is a danger of skin damage, thus our system incorporates an- other alarm unit consisting of a buzzer and second red LED. Both of them transition to operating mode, in case that one of different five time set limits is exceeded. Our system is cheap to manufacture, easy to use and due to FPGA incorpo- ration can be combined with IoT and AI systems. It can also be used in healthcare systems, industrial UV systems and various application systems where ultraviolet radiation is needed.

Keywords: UV, UV index, UV sensor, FPGA, VHDL, LEDs, exposure time.