Digital Thermometer Based on AT89S52

A digital thermometer construction from beginning until the end is illustrated on this project with the use of an 8051 microcontroller and a thermistor.

The digital thermometer was built around the AT89S52 microcontroller while the temperature sensor used is the thermistor that is very suitable for measuring ambient atmospheric temperatures. Any other type of temperature sensor can be used as replacement for as long as it functions in an adequate range for the application. The performance of a thermistor is fairly enough although the response time is relatively big.

An NTC type of thermistor is used for this thermometer, which stands for Negative Temperature Coefficient wherein the resistance decreases with the increase in temperature. The resistance variation should be converted into a voltage variation in order to read the corresponding temperature variation. The conversion is done by inserting the thermistor into a voltage divider.

A linear relation over the concerned operating range exists since the temperature can be translated directly to a proportional voltage. These signals will be converted to digital in order to be read, stored, and displayed by the microcontroller. All 7-segment cells are connected in parallel to display the temperature.

Rest of the project