Global cold-chain logistics demands compact, maintenance-free data loggers that document storage conditions without adding batteries or e-waste. This thesis presents the wireless transmission subsystem of a fully batteryless platform that harvests energy, stores data locally, and transmits it through an NFC link. After researching wireless standards, an ISO 15693/NFC-Forum Type-5 solution built around STMicroelectronics’ ST25DV64KC dynamic tag was selected for its I²C and RF dual-interface, non-volatile EEPROM and energy-harvesting capabilities.

The tag communicates with an ultra-low-power STM32U083 microcontroller over its I²C-bus to store the temperature data. Then, the data is transmitted to the reader via the connected antenna through the 13.56 MHz NFC electromagnetic field. At the same time, the antenna harvests residual energy from the reader, which is stored in an auxiliary capacitor. This stored energy provides a start-up power source for the energy harvesting system. Finally, a Python desktop script translates raw memory blocks into timestamped curves to visualise the logged temperature data.

Tests show that the NFC field of recent smartphones can provide sufficient energy for at least a full system duty-cycle in a single read. Additionally,the ST25DV64KC enables secure, wireless data retrieval , completing the architecture for integration into the project’s complete batteryless logger. Improvements can be made by optimising the auxiliary capacitor storage, antenna design, possible readout by NDEF and the UI by thorough software design.