Design of microcontroller based instrumentation scheme for on-line monitoring and measurement of ambient temperature and relative humidity

This paper describes the development of a reliable temperature and humidity monitoring and measurement system using a high performance 16 - bit microcontroller. The measurement of relative humidity is done using the prin-ciple of psychrometry by electronically measuring the dry and wet bulb temperature at specified air flow velocity. System monitored temperature and relative humidity is from th psychrometric chart. The dry bulb and wet bulb temperature are used for the calculation of RH and the dry bulb temperature shows the ambient temperature. The meas-urement scheme is interfaced with LCD panel for displaying the measured temperatures and RH. The developed system is calibrated and tested in the range of desired accuracy.