Revision 1:8766173d267f, committed 2015-10-19

Comitter:

pro100kot14

Date:

Mon Oct 19 22:03:12 2015 +0000

Parent:

0:1e03d2cd238f

Child:

2:ad2653bcf93f

Commit message:

???????? ?????, ??????????? ?????????? ? ????????? ?????? ? ??????????????.

Changed in this revision

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/Thermistor.cpp	Mon Oct 19 22:03:12 2015 +0000
@@ -0,0 +1,56 @@
+#include "Thermistor.h"
+
+Thermistor::Thermistor(AnalogIn inputChanel, double a, double b, double c):input(inputChanel), error(0){
+    this->a = a;    
+    this->b = b;
+    this->c = c;
+}
+
+double Thermistor::getTemperature(){
+    double temp;
+    double realV;
+    double resistance;
+        //3.3 - ADC maximum
+    realV = input.read()*3.3;
+    resistance = (10000 * 5.0) / realV - 10000;
+        //Considering the error
+    resistance -= error;
+        //Calculations using Steinhart–Hart equation
+    temp = log(resistance);
+    temp = 1/(a+b*temp+c*temp*temp*temp);
+        //Convert from Fahrenheit to Celsius
+    temp -= 273.15;
+    return temp;
+}
+    
+    void Thermistor::setError(double error){
+        this->error = error;
+    }
+    
+    double Thermistor::getError(){
+        return error;
+    }
+    
+    void Thermistor::setCoefficientA(double a){
+        this->a = a;
+    }
+    
+    void Thermistor::setCoefficientB(double b){
+        this->b = b;
+    }
+
+    void Thermistor::setCoefficientC(double c){
+        this->c = c;
+    }
+    
+    double Thermistor::getCoefficientA(){
+        return a;
+    }
+    
+    double Thermistor::getCoefficientB(){
+        return b;
+    }
+    
+    double Thermistor::getCoefficientC(){
+        return c;
+    }
\ No newline at end of file

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/Thermistor.h	Mon Oct 19 22:03:12 2015 +0000
@@ -0,0 +1,88 @@
+#ifndef Thermistor_H
+#define Thermistor_H
+
+#include "mbed.h"
+#include <math.h>
+/**
+* Reads the resistance of thermistor and using Steinhart–Hart equation 
+* converts it to Celsius
+* 
+*/
+class Thermistor{  
+public:
+    /**
+    * Constructor. In the calculations used  a model of 
+    * the resistance of a semiconductor at different temperatures - 
+    * The Steinhart–Hart equation. Need to set the coefficients a, b, c.
+    *
+    * @param inputChanel The analog input is connected to the sensor
+    * @param a Steinhart–Hart coefficient
+    * @param b Steinhart–Hart coefficient
+    * @param c Steinhart–Hart coefficient
+    */
+    Thermistor(AnalogIn inputChanel, double a, double b, double c);
+    
+    /**
+    * The temperature in degrees Celsius
+    * @returns Temperature
+    */
+    double getTemperature();
+    
+    /**
+    * Set error value used in the calculation. 
+    * The resulting resistance is computed as <real resistance> - error;
+    * @param error Error in Ohms
+    */    
+    void setError(double error);
+    
+    /**
+    * Error value used in the calculation
+    * The resulting resistance is computed as <real resistance> - error;
+    * @returns Error in Ohms
+    */
+    double getError();
+    
+    /**
+    * Set a coefficient of Steinhart–Hart equation
+    * @param a a-coefficient 
+    */
+    void setCoefficientA(double a);
+
+    /**
+    * Set b coefficient of Steinhart–Hart equation
+    * @param b b-coefficient 
+    */    
+    void setCoefficientB(double b);
+
+    /**
+    * Set c coefficient of Steinhart–Hart equation
+    * @param c c-coefficient 
+    */    
+    void setCoefficientC(double c);
+    
+    /**
+    * a coefficient of Steinhart–Hart equation
+    * @returns a coefficient 
+    */
+    double getCoefficientA();
+    
+    /**
+    * b coefficient of Steinhart–Hart equation
+    * @returns b coefficient 
+    */
+    double getCoefficientB();
+    
+    /**
+    * c coefficient of Steinhart–Hart equation
+    * @returns c coefficient 
+    */    
+    double getCoefficientC();
+    
+private:
+    AnalogIn input;
+    //Thermistor error in Ohms
+    double error;
+    double a, b, c;
+};
+
+#endif
\ No newline at end of file

--- a/main.cpp	Sat Oct 17 17:14:48 2015 +0000
+++ b/main.cpp	Mon Oct 19 22:03:12 2015 +0000
@@ -1,15 +1,18 @@
 #include "mbed.h"
 #include "USBSerial.h"
-#include <math.h>
 #include "ThermometerTmp36.h"
+#include "Thermistor.h"
 
 USBSerial pc;
-AnalogIn   ain(A0);
+AnalogIn   tmp36(A0);
+AnalogIn   thermist(A2);
 
 int main() {
-ThermometerTmp36 term(ain);
+    ThermometerTmp36 termTmp36(tmp36);
+    Thermistor term503(thermist, 0.001995, 0.00007997, 0.0000003863);
+    term503.setError(-5000);
     while(1) {
-        pc.printf("temperatureC: %f\r\n",term.getTemperature());
+        pc.printf("TMP36: %f degC\tTermistor: %f degC\r\n", termTmp36.getTemperature(), term503.getTemperature());
         wait(1);
     }
 }