Gas Sensing with COTS RFID Devices

Abstract

Gas monitoring, often as a part of safety and health systems, is widely used in a variety of sectors such as manufacturing, auto- mobiles, medical, households, food and beverages, environments, and HVACs. Existing gas monitoring approaches such as the use of catalytic and infrared sensors and electrochemical and metal oxide semiconductor technologies, typically require expensive hardware or are power hungry, and thus not suitable for long-term and large scale deployments. We propose a gas intensity measuring system with cost-effective commercial off-the-shelf (COTS) RFID devices. Our key intuition is that the changes in phase and strength of the signal result from not only the signal propagation but also from the hardware (i.e., tag's circuit). To this end, we propose a method to in- tegrate RFID with a chemiresistor, called Carbon Nanotubes (CNTs), whose electrical property varies with the nearby gas concentration. Our system shows the potential of low-cost, easy-to-make, and wireless sensing based gas monitoring systems.