The LM35 of National Semiconductors that is used in this project is a precision centigrade temperature sensor, which has an analog output voltage. It has a range of -55ºC to +150ºC and a accuracy of ±0.5ºC . The output voltage is 10mV/ºC . The output voltage is converted by the AD convertor of the ATMega8. The temperature is displayed on an LCD module. In this example the thermometer has a range of 0ºC to 40ºC and a resolution of 0.5ºC. ATmega8 is a 8-bit avr famility microcontroller. It has in-built ADC and has many supporting component in it. Its speed is very high, we have used 12Mhz crystal.

ADVANTAGES

• Very low cost circuit.
• Small in size.
• Less power consumption.
• Easy to installation.
• Highly accurate temperature sensing.