Here's one temperature sensor (thermometer) circuit that you can easily build. It uses the popular PIC 16F877A microcontroller. The temperature sensor is LM35. The LM35 outputs an analog voltage proportional to the temperature. The output from the LM35 is 0.1V/'C. So, when temperature sensed is 61'C, the output voltage is 0.61V. This analog voltage is read by the PIC and processed to display the corresponding temperature value on the LCD. The temperature range for this circuit is 0'C to 150'C. The analog to digital conversion is done by the PIC ADC module. In the code, I've used the mikroC library function for ADC. You can view the library file here: http://www.mikroe.com/download/eng/documents/compilers/mikroc/pro/pic/help/adc_library.htm However, you should have a knowledge of how the ADC module works and how to use it. I had written a tutorial on modalities of operation of the PIC 16F877A ADC. You can find the tutorial here: http://www.blogspot.com/2016/03/mo...