Wireless monitoring of temperature and humidity using sensor array

In this paper a wireless based scheme has been proposed for monitoring of temperature and humidity. A highly sensitive signal conditioning circuitry for capacitive humidity and resistive temperature sensors have been developed. The humidity and temperature sensed by these sensors are converted into square waves of central frequencies 101 kHz and ~9 kHz respectively. The sensitivities obtained are 39.1Hz/pF and 234.95 Hz/°C respectively. These two sensing modules have been integrated with a microcontroller unit for signal processing through UART. Further, XBee module of ZigBee based on IEEE802.15.4, has been successfully implemented for wireless transmission and reception.