Steinhart-Thermistor (community library)

Summary

4 coefficients Steinhart version of Thermistor library.

Example Build Testing

Library Read Me

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Steinhart-Thermistor v2

4 coefficients Steinhart version of Thermistor library.

1/T = A + Blog(R/Rt) + Clog(R/Rt)^2 + D**log(R/Rt)^3

In the standard Steinhart-Hart equation the C parameter is set to zero. However, some manufacturers use all 4 coefficients.

Typical usage

Connect a Thermistor to an Analog pin and use the library to get the temperature.

#include "Steinhart-Thermistor.h"

Thermistor Thermistor(A0);

void setup() {
Serial.begin(9600);
}

void loop() {
//Always call calcResistance() first.
//It's the only function that read the ADC value.
//Otherwise you could get a different value for each temperature unit.
//You can specify a number of samples. Default = 1.
Thermistor.calcResistance();
Serial.print("Thermistor resistance: ");
Serial.println(Thermistor.getResistance());
Serial.print("Volts: ");
Serial.println(Thermistor.getVolts());
Serial.print("Analog value at pin: ");
Serial.println(Thermistor.getAval());
Serial.print("Kelvin: ");
Serial.println(Thermistor.getTempK());
Serial.print("Celsius: ");
Serial.println(Thermistor.getTempC());
Serial.print("Fahrenheit: ");
Serial.println(Thermistor.getTempF());
delay(1000);
}

Reference

Thermistor

`int pin = A0; int resistor = 47500; double a1 = 5.36924e-4; double b1 = 1.91396e-4; double c1 = 0; double d1 = 6.60399e-8; float vref = 3.32;

Thermistor Thermistor(pin, resistor, a1, b1, c1, d1, vref);`

Creates an object to interact with the thermistor.

pin is the analog pin number your thermistor is connected to. resistor is the fixed resistor value, for better precision used a multimeter/ohmmeter to mesure the value of the fixed resistor. a1 is the coefficient A (K^0), from the thermistor datasheet. b1 is the coefficient B (K^1), from the thermistor datasheet. c1 is the coefficient C (K^2), usually 0 from the thermistor datasheet. d1 is the coefficient D (K^3), from the thermistor datasheet. vref is the voltage reference, for better precision used a multimeter/voltmeter to mesure voltage pin 3V3 for a Core/Photon/Electron, pin AREF for a Arduino.

calcResistance

Thermistor.calcResistance();

Always call calcResistance() first. It's the only function that read the ADC value. Otherwise you would get a different value for each temperature unit. You can specify a number of samples. Default = 3.

getAval

Thermistor.getAval();

Return the calculated average Analog value of ADC pin.

getResistance

Thermistor.getResistance();

Return the calculated average resistance of the thermistor.

getTempF

Thermistor.getTempF();

Return the calculated temperature in Fahrenheit.

getTempC

Thermistor.getTempC();

Return the calculated temperature in Celcius.

getTempK

Thermistor.getTempK();

Return the calculated temperature in Kelvin.

getVolts

Thermistor.getVolts();

Return the average calculated volts value of ADC pin.

Resource Utilization

Analog pin of your choice.

License

GPL

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