Battery-free wireless sensor sends encrypted indoor environment data
From WPT to Encrypted Telemetry: A Battery-Free Backscattering-based Polarimetric Wireless Sensor
Networking and Internet Architecture
Summary
Many small wireless sensors can't run complex calculations or encrypt their data because they lack batteries. The authors present a sensor that works indoors without batteries by harvesting radio waves for power. This sensor measures temperature, humidity, air pressure, and chemicals in the air, then processes and encrypts that information before sending it wirelessly. Their device combines energy harvesting and communication in a simple antenna design, ensuring reliable and secure data transfer with very low energy use.
What this means in practice
- •For indoor environmental monitoring teams: Deploy battery-free sensors that securely transmit multi-sensor data without needing maintenance or batteries indoors.
- •For building automation engineers: Integrate low-power encrypted wireless sensors to improve secure environmental sensing for smart building controls.
Authors
Taki Eddine Djidjekh, Loïc Thomas, Quentin Bernyer, Gaël Loubet, Daniela Dragomirescu, Alexandru Takacs
Abstract
This work introduces an indoor Battery-Free Wireless Sensing Node powered through radiative Wireless Power Transfer (WPT). The proposed platform targets secure, energyefficient active sensing and overcomes key limitations of many prior battery-free approaches, which commonly provide neither on-node computation nor cryptographic protection. The node combines temperature, humidity, pressure and Volatile Organic Compound (VOC) measurements with a low-power microcontroller that executes sensor calibration, derives a VOC index, formats the payload, and applies AES-128 encryption before wireless transmission. Energy harvesting and communication are enabled by a 1-bit controlled Backscatter Rectenna (BR), which both scavenges incident RF power and produces an orthogonally polarized backscattered signal for robust polarimetric operation. Experimental results validate reliable multi-sensor readout and encrypted data transfer, while maintaining a very low energy budget for the complete sense-compute-encrypt-transmit cycle.