Using millis() for unequal ON/OFF times in nested statements

   okay working on project lm34dz  control digital pin on off attached
to relay. have 3 different temperatures want relay on amount , off
a different amount of time. have done delay's aware causes arduino
to not process during these times.  know 1 solution use millis() , have see code can
have independent on , off times post (listed below conditions).



the temps , on/off times listed here
temp>80°f relay on .5mins off 2.5mins
temp>90°f relay on 1min off 2mins
temp>95°f relay on 2.5mins off .5mins

code unequal intervals http://forum.arduino.cc/index.php?topic=82777.0;wap2

 

code: [select]

unsigned long currenttime = millis();
  if (currenttime > nexttime) {
    if (digitalread(pin)) {
      digitalwrite(pin, low);
      nexttime = currenttime + off_interval;
    } else {
      digitalwrite(pin, high);
      nexttime = currenttime + on_interval;
    }
  }
}

my problem using series of if else if  temperature conditional statements , have variable store
the previous millis , cant seems either reset variable or make independent previous millis varibles , have code work. code have works whatever reason current time gets large ever be
caught if temp changes quickly

i appreciate feel beneficial others.

here code far sorry quite bit repetitive in nature

code: [select]

//code have relay turn on , off @ uneven intervals- in multiple conditional statements
const int threshold1 = 80;
const int threshold2 = 90;
const int threshold3 = 95;
const unsigned long on_interval1=1.5*60*1000;
const unsigned long off_interval1=.5*60*1000;
const unsigned long on_interval2=1*60*1000;
const unsigned long off_interval2=2*60*1000;
const unsigned long on_interval3=.5*1000*60;
const unsigned long off_interval3=2.5*1000*60;
unsigned long nexttime=0;
int ledpin_relay = 13;


void setup() {
  serial.begin(9600);
  pinmode(ledpin_relay, output);
}

void loop() {

  int rawvalue = analogread(a0);

  //next need convert reading voltage value
  //using readanalogvoltage example code can this

  float voltage = rawvalue * (5.0/1023.0);   //here scale raw a/d value voltage
                                             //because using 5v onboard power supply
                                             //our sensor reads in millivolts need convert can see change. the
                                             //lm34dz 10mv per °f (deg symbol done alt+0176)

  float millivolts = voltage * 1000;        //here convert volts millivolts multiplying 1000
  float tempf = millivolts/10;              //because our sensor reads 1 degree farenheit/10mv will
  //divide 10 scale our value

  serial.print (tempf);


  if (tempf > threshold3){
   
    serial.println ("   >95");    //simply print temperature new line
    unsigned long currenttime = millis();
    if (currenttime > nexttime) {
      if (digitalread(ledpin_relay)) {
        digitalwrite(ledpin_relay, low);
        nexttime = currenttime + off_interval1;
      }
      else {
        digitalwrite(ledpin_relay, high);
        nexttime = currenttime + on_interval1;
      }
    }
  }

  else if ( tempf >= threshold2 && tempf <= threshold3) {
   
    serial.println (">90");
    unsigned long currenttime = millis();
    if (currenttime > nexttime) {
      if (digitalread(ledpin_relay)) {
        digitalwrite(ledpin_relay, low);
        nexttime = currenttime + off_interval2;
      }
      else {
        digitalwrite(ledpin_relay, high);
        nexttime = currenttime + on_interval2;
      }
    }
  }

  else if (tempf >= threshold1 && tempf <= threshold2){
    serial.println(">80");
    unsigned long currenttime = millis();
    if (currenttime > nexttime) {
      if (digitalread(ledpin_relay)) {
        digitalwrite(ledpin_relay, low);
        nexttime = currenttime + off_interval3;
      }
      else {
        digitalwrite(ledpin_relay, high);
        nexttime = currenttime + on_interval3;
      }
    }
  }

  else  if (tempf < threshold1) {

    serial.println("<80");
    digitalwrite(ledpin_relay ,low);
  }
   delay(1000);
}










suggest define variables hold current on duration , off duration, record whether output on or off , use compare elapsed time against either on interval or off interval, this:

code: [select]


if(digitalread(pin) == high)
{
    if(millis() - starttime >= onduration)
    {
        starttime += onduration;
        digitalwrite(pin, low);
    }
}
else
{
    if(millis() - starttime >= offduration)
    {
        starttime += offduration;
        digitalwrite(pin, high);
    }
}


i'll leave update current on , off durations depending on temperature.

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