Design and Development of Low Cost PC Based Real Time Temperature and   Humidity Monitoring System
  This paper presents the design and development of a low cost Data Acquisition System (DAS) using PIC12F675 microcontroller for real time temperature and humidity monitoring. The designed DAS has 4 analog input channels having 10-bit resolution and was interfaced through the serial port of the PC. A precision integrated temperature sensor and an instrumentation-quality RH (Relative Humidity) sensor were used for sensing the temperature and humidity respectively. The firmware was written in Basic and compiled using Oshonsoft PIC IDE and downloaded to the microcontroller by using PICkit2 programmer. An application program was also developed using Visual Basic 6, which allows displaying the waveform of the signal(s) in real time and the data can be saved into the hard disk of the computer for future use and analysis. It can also be interfaced to the USB port of the PC or laptop using USB to serial adapter BAFO BF-810. Thus, the designed low cost device works with the legacy hardware as well as the modern USB interface. 
Nungleppam Monoranjan Singh and Kanak Chandra Sarma
cs.OH