Abstract
Thermistors exhibit a nonlinear temperature-resistance response, due to which corrections have to be made when making temperature measurements. In this paper a bio - sensor system is proposed that provides a convenient and non-bulky means of using thermistors in temperature measurements. The system works by maintaining a set point using negative feedback. Compared to traditional thermistor systems, that use linearization technique to improve the linearity of the non-linear response of thermistor, the proposed system uses the graphical approach, hence reducing hardware and eliminating bulky calculations. PIC16F877A micro controller is used for the analysis of data from the patients' end that is then interfaced through USB (Universal Serial Bus) to the software programmed using LAB WINDOWS/CVI 8.0. Biosensor used to test the response of this system is 400 series thermistor as it is sufficiently stable, low cost and has simple interfacing requirements. Also, a communication network based on Star Topology is designed for transferring temperature data from the subject's site to the physician's panel and in turn transferring instructions from main server to the client.