ADC Basics (LM35)

[Danial]

Hi,

i am using an LM35 for sensing temperature. I have a problem to display the right temperature on the LCD. I am using an 8 bit ADC. Therefore, the range is from 0-255 for ADC value. For ADC value of 1, it is equivalent to 0.01953V. If my ADC value is currently 103, then 103 x 0.01953V = 2.0116V. For the LM35, it states that it can read -55C up to 150C and for 10mV/C. If my voltage is 2.0116V, how to display the temperature? Anyone out there that can enlighten me? Thank you very much in advance.

[robosang]

Check out the tutorial from Cytron: http://tutorial.cytron.com.my/2011/08/09/project-5-%E2%80%93-analog-sensor-temperature-using-lm35/

[Danial]

Thanks Robosang.

the programs that you referred is to take the average of 10 adc readings and then just divide by 2. I'll try it.

[ober]

LM35 datasheet stated 0mV + 10mV/degree Celsius. at 0 degree C, the voltage is 0V.

The tutorial that robosang shared is base on 10-bit ADC, you are using 8-bit, you cannot apply that formula.

Find out what is the relationship between degree Celsius and Voltage, replace the Voltage with ADC you get.