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#include<math.h>
int a_InPin = 0; // select the input pin for the potentiometer
int val;
double r0;
double r1;
double r2;
double t0;
double beta;
double vadc;
double vcc;
double vs;
double rs;
double k;
double celsius;
void setup()
{
// begin the serial communication
Serial.begin(9600);
r0 = 10000.0;
r1 = 680;
r2 = 1600;
t0 = 25.0 + 273.15;
beta = 3500.0;
vadc = 5.0;
vcc = 5.0;
vs = (r1 * vcc) / (r1 + r2);
rs = (r1 * r2) / (r1 + r2);
// k = r0 * pow(2.178, (-beta / t0)); // 1.07527403
k = 1.07527403;
}
void loop()
{
int celhold;
val = analogRead(a_InPin); // read the value from the analog pin
celsius = to_temp(val);
Serial.println((long)celsius); // Write the value to the serial port
delay(1000); // stop the program for 1 sec
}
double to_temp(int reading)
{
float v;
double r;
Serial.print("reading:");
Serial.println(reading);
v = (float)((reading * vadc) / 1024.0); // convert the 10 bit ADC value to a voltage
Serial.print("voltage:");
Serial.println((long)(v * 1000));
r = (rs * v) / (vs - v); // resistance of thermistor
Serial.print("resistance:");
Serial.println((long)r);
return ((beta / log(r / k)) - 273.15); // temperature
}
/*
float to_adc(int temp)
{
"Convert a temperature into a ADC value"
r = self.r0 * exp(self.beta * (1 / (t + 273.15) - 1 / self.t0)) # resistance of the thermistor
v = self.vs * r / (self.rs + r) # the voltage at the potential divider
return round(v / self.vadc * 1024) # the ADC reading
}
*/
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