/* NOTE:


External Thermostat using a DS18S20.
This uses two relays hotwired
into a cheap home automation RF remote
to turn one channel on and off.

planning to run this on an ATTiny45

by Non-ICE

edit:
needed to add some self check indicators
since this still is a breadboardbuild

edit II:
this code is attiny45-ready

edit III:
screw tiny45; code is attiny25-ready
*/

#include <OneWire.h>

int settemp=180; //wanted temperature in celsius times 10, was 260???
int DS18S20_Pin = 0; //DS18S20 Signal pin on digital 0
int offpin = 3; //relay for offbutton attached here, also connected a red LED
int onpin = 4; //relay for onbutton attached here
int switchdelay = 5; //minimum delay in seconds between each toggle.

//no changes needed below this point.
int modechange = 15; //toggle timer counter, 15 seconds after boot
int heatstate; //toggle state holder

//Temperature chip i/o
OneWire ds(DS18S20_Pin); // on digital pin 0

void setup(void) {
  pinMode(onpin, OUTPUT);
  pinMode(offpin, OUTPUT);
}

void loop(void) {
  float temperature = getTemp();
  
  
  
  
  
  if (temperature > 40 || temperature < 0) { 
    //if input data  is way off something is wrong give some indication
    digitalWrite(offpin, true);
    delay(5000);
    digitalWrite(offpin, false);
  } else {
    // all ok, do heater toggle
      if (temperature < (settemp/10) && heatstate != onpin) {
        heatstate=onpin;
        heatswitch();
      }
      else {
        heatstate=offpin;
        heatswitch();
      }
    }
  
  
  //if (modechange>0) {modechange=modechange-1;}
  delay(999);
}

void heatswitch(){
  for (int repeats = 0; repeats <= 3; repeats++) { 
    digitalWrite(heatstate, true);
    delay(1500);
    digitalWrite(heatstate, false);
    delay(2000);
  }
  modechange = switchdelay;
}

float getTemp(){
//returns the temperature from one DS18S20 in DEG Celsius

byte data[12];
byte addr[8];


// error checking
if ( !ds.search(addr)) {
  //no more sensors on chain, reset search
  ds.reset_search();
  return -1000;
}

if ( OneWire::crc8( addr, 7) != addr[7]) {
  //Serial.println("CRC is not valid!");
  return -1000;
}

if ( addr[0] != 0x10 && addr[0] != 0x28) {
  //Serial.print("Device is not recognized");
  return -1000;
}


//read DS
ds.reset();
ds.select(addr);
ds.write(0x44,1); // start conversion, with parasite power on at the end

byte present = ds.reset();
ds.select(addr);
ds.write(0xBE); // Read Scratchpad


for (int i = 0; i < 9; i++) { // we need 9 bytes
data[i] = ds.read();
}

ds.reset_search();

byte MSB = data[1];
byte LSB = data[0];

float tempRead = ((MSB << 8) | LSB); //using two's compliment
float TemperatureSum = tempRead / 16;

return TemperatureSum;

}