Multiscale Digital Thermometer

A digital thermometer is an instrument used to automatically measure the temperature of a substance or the surroundings. In this project a multiscale digital thermometer was designed. In our design there was three main parts 1. Sensor 2. Microcontroller 3. LCD display parts. A DC voltage was developed at the output of the sensor (LM35) depending on the temperature of the body to be measured. For an increase of every 1 degree centigrade of temperature an increase of 10mv voltage at the sensor output was found. We could measure the magnitude of temperature ranging from 0 to 102 degree centigrade with this thermometer and the corresponding sensor voltage output was found to be in the range of 0-1 volt. The sensor output was connected to the microcontroller input. The measured value of the temperature was displayed through an LCD display in the unit of Fahrenheit, Centigrade and Kelvin. The whole set up was mounted on a breadboard and every section of the circuit was tested individually. After getting satisfactory result every section was jointed. The response time of the thermometer was found to be of maximum 15 seconds. The total cost of the project was BDT-800/- only.