Simple cost effective and network compatible readout for capacitive and resistive (chemical) sensors

The described application directs the integration of capacitive and resistive sensors for environmental parameters monitoring (CO2, relative humidity, dew point and temperature) in low cost applications which can be made on flexible substrate, which was developed in the European FP7 project INTERFLEX [1]. This type of applications on plastic substrates requires a reduction of amount and type of components in order to reduce costs through simplification of assembly processes as well as enhancement of the reliability. This paper describes a very simple low power and cost effective architecture for readout of capacitive and resistive sensors, which uses few external components, exploiting a STMicroelectronics STM8L15x microcontroller and sensors developed by Fraunhofer Research Institu tion for Modular Solid State Technologies (EMFT).