Wireless smart tag with on-board conductometric chemical sensor

Abstract

A contactless smart card with integral wireless power and data link and on-board chemical sensor is described. The chemical sensor part of the smart card comprises a planar conductometric interface onto which a chemically or biologically sensitive thin film may be cast using microfabrication techniques. The thin film sensor and conductometric interface form an integral part of a radio-frequency smart card that has been designed for use in distributed chemical and biological detection systems, and which is based upon the International Standards Organisation high-frequency (HF) ISO 15693 radio-frequency identification (RFID) protocol. Conductometric measurements are controlled, sampled and stored by the smart card electronics. Measurement results achieved with an organic semiconductor, poly(3,4-ethylenedioxythiophene) poly(styrenesulfonate), PEDOT-PSS, as a model thin film conductometric sensor material cast on planar gold electrodes are reported. The standardisation of short-range wireless radio protocols such as Bluetooth, RuBee, ZigBee, WiFi and RFID is opening new markets for distributed sensors and sensor networks, and the fusion of chemical and biosensor technologies with short-range, low-cost, wireless technologies will create new opportunities for chemical and biological sensor systems in healthcare, environmental monitoring, process and quality control, and chemical and biological threat detection. The chemical sensor smart card described here could in future be suitable for use in various distributed short range wireless data applications and sensor networks as part of the emerging sensor Internet of Things.