08-12-2014, 05:30 AM
Analysis of the circuit diagram of LM35 with ATMEGA32
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The LM35 series is a low cost and precision integrated circuit temperature sensor whose output voltage is proportional to the centigrade temperature scale. Therefore, LM35 has an advantage over other temperature sensors calibrated in Kelvin since users do not require the subtraction of a large constant voltage to obtain the required temperature of centigrade. It does not require any external calibration. It is produced by National Semiconductor and can operate in a temperature range of -55 ° C to 150 ° C. Its output is linearly proportional to the centigrade temperature scale and its output changes by 10 mV per ° C.
Interconnect an LM35 temperature sensor with the AVR ATMega32 microcontroller and the LCD display. Here, we are going to measure the temperature of the surrounding material or any other material to which the LM35 temperature sensor is connected for its temperature measurement and show the temperature value in degree centigrade on a 16X2 alphanumeric LCD. But, the output of the temperature sensor LM35 is analogous in nature and the microcontroller can not process the analog signal directly. Therefore, you will first convert the analog output of the LM35 temperature sensor to digital values using your analog-to-digital converter and then process the digital value to convert the digital value to a degree centigrade value. The microcontroller will then display the temperature in degree centigrade on the 16X2 alphanumeric LCD. Now, light a match stick or lighter near the LM35 temperature sensor and see the changes in its output value on the 16X2 alphanumeric LCD.