53 lines
1.4 KiB
C
53 lines
1.4 KiB
C
#include "themistor-temp.h"
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void init_led(){
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PORTB.DIRSET = ledpin;
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}
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// The code is inspired by "Arduino thermistor guide" by valtentina Vogelman, 1 november 2023
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// https://www.build-electronic-circuits.com/arduino-thermistor/
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float calculate_thermistor_temp(float thermistor_voltage){
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float R_thermistor;
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float V_1;
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float ln;
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float T_thermistor;
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float V_thermistor;
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#define V_TOT 5
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// Calculate Voltage over thermistor
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V_thermistor = (V_TOT/1024)*thermistor_voltage;
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// Voltage accross R_1
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V_1 = V_TOT - V_thermistor;
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// Calculate Thermistor resistanse
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R_thermistor = (V_thermistor)/ (V_1 / R_1);
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// Steinhart-Harts formula
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ln = log(R_thermistor/R_T0);
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T_thermistor = (1/ ((ln/B) + (1/T_0)));
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// Temperatur in celcius
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T_thermistor -= 273.15;
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return T_thermistor;
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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 voltage_threshold_bool(float thermistor_temp, uint8_t max_temp){
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// Return true if temp is higher then max value
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return (thermistor_temp >= max_temp);
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}
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//print if the maximum threshold is exceeded.
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void alert_voltage_threshold_exceeded(bool voltage_threshold_bool){
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if (voltage_threshold_bool){
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printf("Error: maximum temperature exceeded");
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PORTB.OUTSET = ledpin;
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} else{
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PORTB.OUTCLR = ledpin;
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}
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}
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