#include <TinyDebug.h>


#define TempInputPin PB3
#define FanCtlPin PB1

//Need to test but calculated temp to voltage
//Temp = Volt = ADC Reading @ 2.5V Ref
//20C = 0.45V = 186 
//30C= 0.58V = 238
//40C= 0.83V - 341
//50C= 1.16V = 476
//60C= 1.56V = 636

const uint16_t OnThreshold=425;
const uint16_t OffThreshold=275;

uint16_t CheckThreshold = OnThreshold;
uint16_t temp;
 
uint32_t FanSwitchTime;
const uint32_t FanOnOverLoad = 5000; //45min x 60000ms/min 
const uint16_t checktime=1000;//how often to check temp
uint32_t lastcheck=0;

bool FanOn = false;

void setup() {
  Debug.begin();
  //analogReference(INTERNAL2V5);
  pinMode(TempInputPin,INPUT);
  pinMode(FanCtlPin,OUTPUT);digitalWrite(FanCtlPin,FanOn);
}

void loop() {
  uint32_t ms=millis();
  if (ms-lastcheck > checktime){ // only check temp once per checktime (default 1 sec)
    temp=analogRead(TempInputPin);//number goes up as temp goes up;
    //Debug.println(temp);
    //Debug.println(CheckThreshold);
    if ((FanOn) ? (temp < CheckThreshold) : (temp > CheckThreshold)){
        ToggleFan(ms);//Toggle Fan On/Off once threshold reached
      }
   lastcheck = ms;   
  }
  
  if (FanOn && (ms - FanSwitchTime > FanOnOverLoad)){//check if fan on for more than X minutes and turn Off if so
    ToggleFan(ms);//Toggle Fan Off
  }
}


void ToggleFan(uint32_t _ms){
  FanOn=!FanOn; //Toggle Fan On/Off once threshold reached
  digitalWrite(FanCtlPin, FanOn);
  FanSwitchTime = _ms;
  CheckThreshold = (CheckThreshold == OnThreshold ? OffThreshold : OnThreshold);//toggle CheckThreshold
}