The LM335AZ is a cheap (0,75 €) temperature sensor that reads the surrounding temperature and is calibrated in degrees Kelvin. The LM335 has an output from −40°C to 100°C.


The LM335 sensor outputs 10mV/°K. So if the LM335 is giving an output reading of 2.943 (which is 2943mV), this is equivalent to a temperature of 294.3° Kelvin. All you have to do is take the output reading and divide it by 10 in order to get the temperature. This output reading of 294.3° kelvin is equivalent to 21.11°C.

In this circuit we will use the LM335 IC to measure the temperature. We will connect it to the ATMega328 Board to measure the temperature. The ATMEGA328 Board will then read this measured value from the LM335 and translate it into millivolt, degrees kelvin, and celsius, then we will send the output to the LCD display. The AVRGCC compiler will be used to make the program.