LED powered identification tag - energy harvesting and power consumption optimization

This paper presents an ID tag concept which is LED powered. The photovoltaic effect of the LED array is used to harvest energy from ambient light or from light source in reader device in order to power the tag. Harvested energy is stored in a capacitor that is used to supply ID tag logic which transmits ID information using one diode of LED array which is also used for powering. The powering circuit, i.e. LED energy harvester is tested for various commercially available LEDs, to determine the most suitable LED type with respect voltage gain and current drivability. The power consumption of presented LED ID tag is optimized using Response Surface Methodology with respect to the following input parameters: frequency of operation, frequency of data transmission and the data packet length with respect to the consumed power and the transmission distance. The optimization proposes optimal input parameters for minimum power consumption and maximum operating distance, presenting a compromise between the aforementioned parameters in reference to the input variables.