A Battery-less Contact Lens Sensor Prototype with Enhanced Performance for Cattle Health Monitoring

This paper presents a low-cost, non-invasive, and fully integrated smart NFC sensor tag for cattle health monitoring. The proposed sensor solution operates without a battery and has the potential to measure the body temperature and health status of cattle. This paper expands on previous work in this area by the authors and demonstrates significant performance improvements, including flexibility for sensor replacement, simplified programming interfaces, and an extended wireless range. Among the various electronic components on the proposed NFC sensor tag, the microcontroller is identified as the most power-consuming, constituting over 76% of the total power consumption. Therefore, voltage and frequency scaling for the microcontroller have been employed to minimize the overall DC power consumption of the sensor tag. Furthermore, with an NFC-enabled smartphone, the developed sensor prototype achieves a measured wireless range of approximately 12 mm. Future work will investigate the further optimization of the smart contact lens for in-vivo operation.