Physical quantities like Humidity, temperature, pressure etc. are monitored to get information about the environmental conditions. Various sensors are being used to measure these quantities in analog form. This article on Interfacing humidity sensor demonstrates the principle and operation of interfacing the humidity sensor with 8051 microcontroller (AT89C51). The humidity sensor is widely used in applications like weather forecast, air conditioner, Hygrometers etc.
Please visit Interfacing humidity sensor
for circuit, C code, description and components used.