Fluctuating temperature using NTC

Other Hardware Sensors
6

So what you see is the natural noise on the analogRead() --> solution make 32 (or more) analogRead's and average them

snippet:

float sum = 0;
for (int i=0; i< 32; i++) sum += analogRead(A0);
sum /= 32;
Vout=(Vin/1024)*(sum);
Rntc=(Vout*Rfija)/(Vin-Vout);
TempK = Beta/(log(Rntc/R25)+(Beta/T0));
TempC = TempK-273.15;