Okay so when I copied the code over and changed the resistor value to 10000. I am getting inf as the output of average. So to me it looks like there doing a mathematical equation for your analog reading to convert to a resistance reading. So im just getting confused in this code on where I change my resistance values according to temp. In there code they said "For this one we only need to know To (which is room temperature, 25 °C = 298.15 K)" so Im guessing since im getting inf as my output that something isnt calibrated right? what in this code do I change?
or am I getting ahead of myself here. Do I use there first code that does print your thermal resistance? then heat my plate take temp to resistance recordings and thats how I find my coefficient? is that what changes?
// which analog pin to connect
#define THERMISTORPIN A0
// resistance at 25 degrees C
#define THERMISTORNOMINAL 32000
// temp. for nominal resistance (almost always 25 C)
#define TEMPERATURENOMINAL 25
// how many samples to take and average, more takes longer
// but is more 'smooth'
#define NUMSAMPLES 5
// The beta coefficient of the thermistor (usually 3000-4000)
#define BCOEFFICIENT 3950
// the value of the 'other' resistor
#define SERIESRESISTOR 32000
uint16_t samples[NUMSAMPLES];
void setup(void) {
Serial.begin(9600);
analogReference(EXTERNAL);
}
void loop(void) {
uint8_t i;
float average;
// take N samples in a row, with a slight delay
for (i=0; i< NUMSAMPLES; i++) {
samples[i] = analogRead(THERMISTORPIN);
delay(10);
}
// average all the samples out
average = 0;
for (i=0; i< NUMSAMPLES; i++) {
average += samples[i];
}
average /= NUMSAMPLES;
Serial.print("Average analog reading ");
Serial.println(average);
// convert the value to resistance
average = 1023 / average - 1;
average = SERIESRESISTOR / average;
Serial.print("Thermistor resistance ");
Serial.println(average);
float steinhart;
steinhart = average / THERMISTORNOMINAL; // (R/Ro)
steinhart = log(steinhart); // ln(R/Ro)
steinhart /= BCOEFFICIENT; // 1/B * ln(R/Ro)
steinhart += 1.0 / (TEMPERATURENOMINAL + 273.15); // + (1/To)
steinhart = 1.0 / steinhart; // Invert
steinhart -= 273.15; // convert to C
Serial.print("Temperature ");
Serial.print(steinhart);
Serial.println(" *C");
delay(1000);
}