cattledog:
516 9825.58 25.13 <<<< approx 10K for 25C
good spot, I did not even notice that. the problem is that the real temp at that point was about 60C not 25.13C as logged with Serial.print
I'm confused. The post #`15 data looks correct.
Thermistor temperature measurement:
Vo R2 T (C) REAL TEMP
329 21094.23 6.44 20C
392 16096.94 12.84 30C
439 13302.96 17.50 40C
479 11356.99 21.44 50C
516 9825.58 25.13 60C
547 8702.01 28.28 70C
Is that taken from the potentiometer simulating the thernistor, or is it from the thermistor?
it is a real thermistor on analog Pin 2 Vout FROM the thermistor
int ThermistorPin = A2;
what I wanted to do with this code, was just to read the Vout TO the thermistor eg.5V(or in my case 4.58V because I am using USB to test and power. when not testing, I will use the 12V in)
int analogPin = 3; // potentiometer wiper (middle terminal) connected to analog pin 3
// outside leads to ground and +5V
int val = 0; // variable to store the value read
void setup()
{
Serial.begin(9600); // setup serial
}
void loop()
{
val = analogRead(analogPin); // read the input pin
Serial.println(val); // debug value
}
.
.
.
*** I do not understand this part: ***
R2 = R1 * (1023.0 / (float)Vo - 1.0);
" R2 = R1 x (Vin/Vout −1) "
[Vout: voltage between thermistor and known resistor]
[Vin: Vcc i.e. 5V]
[R1: known resistor value]
[R2: resistance of thermistor]
*** is the 'Vin' measured internally somehow or dose the '1023' just refer to '5V' ***