Hi, im new to the arduino and am having some trouble with the code. I am trying to get some software together to run a fuel burning heater (perfectly safe as its only burning waste oil) but cant get it to work. Once the program is running it goes through the startup procedure reading the initial temperature however after 60 seconds it should re-read the new temperature and run according but it is just repeating the initial temp reading regardless of the thermocouple current temperature. I am using a max6675 with a k type thermocouple. If theres anybody out there that could help I would greatly appreciate it as I have been trying to solve the problem for weeks! 
Thankyou.
Here is the code im using.
#include <max6675.h>
// Define constants
#define ON 1
#define OFF 0
#define REMOTE_STARTING 2
#define REMOTE_STOPPING 3
#define REMOTE_SHUTDOWN 4
#define SYSTEM_STOPPING 5
#define SYSTEM_SHUTDOWN 6
// Define service variables
boolean debug = true;
volatile long lastDebounceTime = 0;
// Define global variables
int onOffSwitch = 2;
int airFan = 3;
int fuelPump = 4;
int waterPump = 5;
int glowPlug = 6;
int cabinHeater = 8;
int remoteControl = 9;
int carBlinkers = 10;
// Thermocouple 0 = CS, 1 = CLK, 2 = DO
int tempSensor[3] = { 11, 12, 13 };
// Setting
volatile int startingAttempts = 0;
int maxStartingAttempts = 3;
int temperatureThreshold = 10;
int maxTemperature = 70;
double initialTemperature;
double previousTemperature;
// Define system states (ON, OFF, REMOTE_STARTING, REMOTE_STOPPING, REMOTE_SHUTDOWN, SYSTEM_STOPPING, SYSTEM_SHUTDOWN)
volatile int systemState = OFF;
// Define modules states
int airFanState = OFF;
int waterPumpState = OFF;
int glowPlugState = OFF;
int cabinHeaterState = OFF;
int remoteControlState = ON;
// Initialize temperature sensor
MAX6675 thermocouple(tempSensor[1], tempSensor[0], tempSensor[2]);
// Setup the controller
void setup(){
// Is debug on
if(debug == true){
// Enable serial connection
Serial.begin(9600);
}
// Set modules modes
pinMode(fuelPump, OUTPUT);
pinMode(waterPump, OUTPUT);
pinMode(glowPlug, OUTPUT);
pinMode(airFan, OUTPUT);
pinMode(cabinHeater, OUTPUT);
pinMode(carBlinkers, OUTPUT);
pinMode(remoteControl, OUTPUT);
// Set ON/OFF switch to ON (internal pull-up resistor)
digitalWrite(onOffSwitch, HIGH);
// Attach interrupt
attachInterrupt(0, turnOnOffSystem, CHANGE);
// Reset all modules
resetAllModules();
}
// Start the controller
void loop(){
// If system has to be started or is already started
if(systemState == REMOTE_STARTING || systemState == ON){
// If starting from remote
if(systemState == REMOTE_STARTING){
// Blink the sideblinkers
if(blink(2, true, false)) return;
}
// Set initial temperature
initialTemperature = measureTemp(3);
// If temperature is above max temperature level or temperature sensor is off
if(!initialTemperature || initialTemperature >= maxTemperature){
// If heater was running
if(systemState == ON){
// Set system state
systemState = SYSTEM_STOPPING;
}
// If heater is starting
else {
// Set system state
systemState = SYSTEM_SHUTDOWN;
}
// Stop webasto starting cycle
return;
}
// Is debug on
if(debug == true){
// Log
Serial.print("Initial temperature: ");
Serial.print(initialTemperature);
Serial.println();
}
// Start the Webasto heater
startWebasto();
}
// If system has to be stopped
else if(systemState == REMOTE_STOPPING || systemState == SYSTEM_STOPPING){
// Stop remote control receiver
stopRemoteControlReceiver();
// If stopping from remote
if(systemState == REMOTE_STOPPING){
// Blink the sideblinkers
blink(4, false, false);
}
// Stop the Webasto heater
stopWebasto();
}
// If system has to be shutdown
else if(systemState == REMOTE_SHUTDOWN || systemState == SYSTEM_SHUTDOWN){
// If shutting down from remote
if(systemState == REMOTE_SHUTDOWN){
// Blink the sideblinkers
if(blink(4, true, false)) return;
}
// Reset all modules
resetAllModules();
// Set system state
systemState = OFF;
}
}
// Turn ON/OFF system from remote control
void turnOnOffSystem(){
// Get current time
long currentTime = millis();
// Debounce
if ((currentTime - lastDebounceTime) > 100){
// Record last debounce time
lastDebounceTime = currentTime;
// If system is still starting
if(systemState == REMOTE_STARTING){
// Turn system off immediately
systemState = REMOTE_SHUTDOWN;
}
// If system is on
else if(systemState == ON){
// Turn system off
systemState = REMOTE_STOPPING;
}
// If system is off
else if(systemState == OFF){
// Turn system on
systemState = REMOTE_STARTING;
// Clear all previous starting attempts
startingAttempts = 0;
}
}
}
// Start the webasto heater
void startWebasto(){
// If this is first, second or third attempt
if(startingAttempts < maxStartingAttempts){
// Is debug on
if(debug == true){
// Log
Serial.println(“Starting the heater”);
}
// Increment attempt
startingAttempts++;
// Reset all modules
resetAllModules();
// Start the air fan to clean the carbon
startAirFan();
// Wait and interrupt on system state change and temperature change
if(wait(15000, true, true)) return;
// Stop air fan
stopAirFan();
// Start water pump
startWaterPump();
// Wait and interrupt on system state change and temperature change
if(wait(15000, true, true)) return;
// Set system state
systemState = ON;
// Start glow plug
startGlowPlug();
// Wait and interrupt on system state change and temperature change
if(wait(5000, true, true)) return;
// Start the combustion process
for(int i = 0; i <= 1000; i++){
// Supply fuel to the burner while checking for state change
if(pulseFuelPump(true, true)) return;
// 15th second from start of the burning process
if(i == 15){
// Start the air fan
startAirFan();
}
// 20th second from start of the burning process
else if(i == 20){
// Stop the glow plug
stopGlowPlug();
}
// 60th second and above from start of the burning process
else if(i >= 60){
// Check temperature
double temperature = measureTemp(3);
// If temperature sensor is off
if(!temperature){
// Go to shutdown mode
systemState = SYSTEM_STOPPING;
// Stop the burning process
return;
}
// 60th second
if(i == 60){
// If temperature threshold is not reached
if(initialTemperature + temperatureThreshold > temperature){
// Is debug on
if(debug == true){
// Print error
Serial.print("Initial temperature: ");
Serial.print(initialTemperature);
Serial.print(", Current temperature: ");
Serial.print(temperature);
Serial.println();
Serial.println(“Temperature threshold not reached!”);
}
// Restart the burning process
return;
}
// Is debug on
if(debug == true){
// Log
Serial.print("Initial temperature: ");
Serial.print(initialTemperature);
Serial.print(", Current temperature: ");
Serial.print(temperature);
Serial.println();
Serial.println(“Temperature threshold reached, continuing the burning process”);
}
// Log the current temperature
previousTemperature = temperature;
// Start the cabin heater
startCabinHeater();
}
// Above 60th second
else {
// If temperature has increased
if(temperature >= previousTemperature && temperature <= previousTemperature + 2){
// Log the current temperature
previousTemperature = temperature;
}
// If temperature has decreased
else if(temperature <= previousTemperature && temperature >= previousTemperature - 2){
// Is debug on
if(debug == true){
// Print error
Serial.print("Previous temperature: ");
Serial.print(previousTemperature);
Serial.print(", Current temperature: ");
Serial.print(temperature);
Serial.println();
Serial.println(“Temperature has decreased, possible flame extinguishing!”);
}
// Restart the burning process
return;
}
}
}
// Wait and interrupt on system state change and temperature change
if(wait(700, true, true)) return;
}
// Go to shutdown mode
systemState = SYSTEM_STOPPING;
}
// If we have tried three times starting the Webasto
else {
// Set system state
systemState = SYSTEM_STOPPING;
}
}
// Stop the webasto heater
void stopWebasto(){
// Is debug on
if(debug == true){
// Log
Serial.println(“Shutting down”);
}
// Stop fuel burning and cabin heater
stopGlowPlug();
stopCabinHeater();
// Start the water pump and air fan
startWaterPump();
startAirFan();
// Wait without checking for system state change and temperature change
wait(60000, false, false);
// Set system state
systemState = OFF;
// Reset all modules
resetAllModules();
// Is debug on
if(debug == true){
// Log
Serial.println(“Done”);
}
}
// Pulse fuel pump
boolean pulseFuelPump(boolean stateChangeInterrupt, boolean tempChangeInterrupt){
// Start fuel pump
digitalWrite(fuelPump, ON);
// Sleep for 100 miliseconds and return true on state or temperature change
if(wait(100, stateChangeInterrupt, tempChangeInterrupt)) return true;
// Stop fuel pump
digitalWrite(fuelPump, OFF);
// Is debug on
if(debug == true){
// Log
Serial.println(“Pulse fuel”);
}
// Return false
return false;
}
// Start air fan
void startAirFan(){
// Start the air fan
digitalWrite(airFan, ON);
// Set module status
airFanState = ON;
// Is debug on
if(debug == true){
// Log
Serial.println(“Air fan on”);
}
}
// Stop air fan
void stopAirFan(){
// Start the air fan
digitalWrite(airFan, OFF);
// Set module status
airFanState = OFF;
// Is debug on
if(debug == true){
// Log
Serial.println(“Air fan off”);
}
}
// Start water pump
void startWaterPump(){
// Start the water pump
digitalWrite(waterPump, ON);
// Set module status
waterPumpState = ON;
// Is debug on
if(debug == true){
// Log
Serial.println(“Water pump on”);
}
}
// Stop water pump
void stopWaterPump(){
// Start the water pump
digitalWrite(waterPump, OFF);
// Set module status
waterPumpState = OFF;
// Is debug on
if(debug == true){
// Log
Serial.println(“Water pump off”);
}
}
// Start glow plug
void startGlowPlug(){
// Start the glow plug
digitalWrite(glowPlug, ON);
// Set module status
glowPlugState = ON;
// Is debug on
if(debug == true){
// Log
Serial.println(“Glow plug on”);
}
}
// Stop glow plug
void stopGlowPlug(){
// Start the glow plug
digitalWrite(glowPlug, OFF);
// Set module status
glowPlugState = OFF;
// Is debug on
if(debug == true){
// Log
Serial.println(“Glow plug off”);
}
}
// Start cabin heater
void startCabinHeater(){
// Start the cabin heater
digitalWrite(cabinHeater, ON);
// Set module status
cabinHeaterState = ON;
// Is debug on
if(debug == true){
// Log
Serial.println(“Cabin heater on”);
}
}
// Stop cabin heater
void stopCabinHeater(){
// Start the cabin heater
digitalWrite(cabinHeater, OFF);
// Set module status
cabinHeaterState = OFF;
// Is debug on
if(debug == true){
// Log
Serial.println(“Cabin heater off”);
}
}
// Start remote control receiver
void startRemoteControlReceiver(){
// Start the remote control receiver
digitalWrite(remoteControl, OFF);
// Set module status
remoteControlState = ON;
// Is debug on
if(debug == true){
// Log
Serial.println(“Remote control receiver on”);
}
}
// Stop remote control receiver
void stopRemoteControlReceiver(){
// Stop the remote control receiver
digitalWrite(remoteControl, ON);
// Set module status
remoteControlState = OFF;
// Is debug on
if(debug == true){
// Log
Serial.println(“Remote control receiver off”);
}
}
// Measure unit temperature
double measureTemp(int maxRetries){
// Init temperature variable
double temperature = NAN;
// Loop until max retries number is reached
for (int i = 0; i < maxRetries; i++){
// Measure temperature
temperature = thermocouple.readCelsius();
// If temperature reading is ok
if (!isnan(temperature)){
// Exit on first good reading
break;
}
}
// If temperature sensor is off
if (isnan(temperature)) {
// Is debug on
if(debug == true){
// Print error
Serial.println(“Thermocouple not responding!”);
}
// Return false
return false;
}
// If temperature is ok
else {
// Return temperature
return temperature;
}
}
// Reset all modules
void resetAllModules(){
// Turn off all modules
stopWaterPump();
stopGlowPlug();
stopAirFan();
stopCabinHeater();
// Turn on remote control receiver
startRemoteControlReceiver();
}
// Blink car blinkers
boolean blink(int times, boolean stateChangeInterrupt, boolean tempChangeInterrupt){
// Start the loop
for(int i = 0; i < times; i++){
// Turn on blinkers
digitalWrite(carBlinkers, ON);
// Sleep for 0.2 seconds and listen for system state and temperature change
if(wait(200, stateChangeInterrupt, tempChangeInterrupt)) return true;
// Turn off blinkers
digitalWrite(carBlinkers, OFF);
// Sleep for 0.2 seconds and listen for system state and temperature change
if(wait(200, stateChangeInterrupt, tempChangeInterrupt)) return true;
// Is debug on
if(debug == true){
// Log
Serial.println(“Blink”);
}
}
// Return false if system state or temperature have not changed
return false;
}
// Custom delay
boolean wait(unsigned long milliseconds, boolean stateChangeInterrupt, boolean tempChangeInterrupt){
// Record current time
unsigned long currentTime = millis();
// Get current system state
int currentSystemState = systemState;
// Init temperature variable
double temperature;
// Loop until time limit is reached
while (millis() - currentTime <= milliseconds) {
// If temperature change interrupt is on
if(tempChangeInterrupt == true){
// Measure temperature
temperature = measureTemp(3);
// If temperature is off or above max temperature level
if(!temperature || temperature >= maxTemperature){
// Is debug on
if(debug == true){
// Print error
Serial.print("Current temperature: ");
Serial.print(temperature);
Serial.println();
Serial.println(“Max temperature reached!”);
}
// If temperature critical level is reached return true
return true;
}
}
// If state change interrupt is on
if(stateChangeInterrupt == true){
// Check if system state has changed
if(systemState != currentSystemState){
// Update the current system state
currentSystemState = systemState;
// If system state has changed return true
return true;
}
}
}
// Return false if system state has not changed
return false;
}