40 lines
972 B
C
40 lines
972 B
C
#include "themistor-temp.h"
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float calculate_thermistor_temp(float readValue){
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float R_therm;
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float V_1;
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float ln;
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float T_therm;
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float V_therm;
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uint8_t V_tot = 5;
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// Calculate Voltage over thermistor
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V_therm = (V_tot/1024)*readValue;
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// Voltage accross R_1
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V_1 = V_tot - V_therm;
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// Calculate Thermistor resistanse
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R_therm = (V_therm)/ (V_1 / R_1);
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// Steinhart-Harts formula
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ln = log(R_therm/R_t0);
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T_therm = (1/ ((ln/B) + (1/T_0)));
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// Temperatur in celcius
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T_therm -= 273.15;
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return T_therm;
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}
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// returns error message if the messured thermistor temp is higher than
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// Choosen max_temp
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bool error_message(float thermistor_temp, uint8_t max_temp){
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// Return true if temp is higher then max value
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if (thermistor_temp >= max_temp){
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printf("Error");
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return true;
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}
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else {
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return false;
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}
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} |