I have created a temp sensor using 89c2051.This sensor uses LM35 to sense the temp.I use a 0804 adc chip for a/d conversion.I send the temp reading to PC .I have a interface on the pc.The problem is that the temp is read and sent to the pc.But take for example it is room temperature.The reading shown is sometimes 31degreeC sometimes 32 or sometimes 33.I get the temp values when i press a button on the interface.But even if i press the button fast enoughsay in the same time frame.the reading changes in the range as mentioned above.Why could this be happening.I measured the voltage at Vout of LM35.It shows .31v.