Specifying state of digital pin, but state fluctuates

hello,

i'm marine biologist, not programmer, thought had code pretty figured out until now. project, trying control both heater , valve. @ particular time of day (low tide) want valve open (letting water out) , heater come on.

the issue arose morning, hadn't been issue before, has controlling valve (seemingly easiest part of project)

some background on code:

currently, enter low tide start time in 2 parts such (lowtidestarttimehr = 10, lowtidestarttimemin = 30) low tide starting @ 10:30. same end of low tide. convert these 2 times minutes (lowtidestarttime = lowtidestarttimehr * 60 + lowtidestarttimemin) using current time (from rtc) , series of  "if else" statements determine if low tide. section of code shown below. there's added complication there 2 low tides each day there both "lowtidestarttime_1" , "lowtidestarttime_2", specified in same manner , "if else" statements, if bit long, not complicated.

code: [select]

void tidevalve()
    {
    // current time, store in object 'now'
      datetime = rtc.now();
     
      if(now.hour()*60+now.minute() >= lowtidestarttime_1 && now.hour()*60+now.minute() < lowtideendtime_1 || now.hour()*60+now.minute() >= lowtidestarttime_2 && now.hour()*60+now.minute() < lowtideendtime_2 ) //if low tide
     {
       digitalwrite(lowtiderelay, high); //turn on relay1 power (open) valve
       digitalwrite(lowtide_led, high);   // turn on indicator led
      }
       else if(now.hour()*60+now.minute() < lowtidestarttime_1 || now.hour()*60+now.minute() >= lowtideendtime_1 || now.hour()*60+now.minute() < lowtidestarttime_2 || now.hour()*60+now.minute() >= lowtideendtime_2) //if high tide
              {
                digitalwrite(lowtiderelay, low);  //switch relay1 (close valve)
                digitalwrite(lowtide_led, low);    //turn off indicator led
              }
    }

the issue have run "lowtiderelay" pin doesn't seem stay high or low during high or low tide periods, switches "randomly".

i used serial port see what's going on , posted small section of below. printed additional output variables explore if fluctuation associated other change in system.
the variables have in output posted below are: "datetime", "measured temp", "set temp", "valvestate, equals relay pin", "current time", "lowtidestart", "lowtideend".

the primary column of interest valve state. when "time" between "lowtidestart" , "lowtideend", state should high (1). is. have attached file followed same timeline longer (and across switch low tide high tide) , can see state fluctuates , forth 0 1. seems have pattern, , gets random. when time greater lowtideend (its no longer low tide , state should low (0)), valve more 1, still fluctuates , forth (see attached file).

i'm not sure what's going on here, need valve/relay/pin maintain 1 state during "low tides" (valve open) , opposite state during "high tides" (valve closed) , right doesn't seem doing this.

additionally, i'm not happy way timing of tides set because it  restricts timing of low tides cannot extend 1 day next (over midnight). so, open thoughts on how avoid whole mess, rewrite code, , specify timing of tides in different manner may not result in behavior seeing now.

i have attached full code, longer serial output, possible see valve state switches.

maybe simple mistake of not specifying initial state , appreciate feedback well.

thank you,
nate

code: [select]


2014/3/18 12:11:51,    21.31 deg.c,   set temp: 13.10 valvestate: 0 time: 731 lowtidestart: 360 lowtideend; 735
2014/3/18 12:11:54,    21.31 deg.c,   set temp: 13.10 valvestate: 0 time: 731 lowtidestart: 360 lowtideend; 735
2014/3/18 12:11:58,    21.31 deg.c,   set temp: 13.10 valvestate: 0 time: 731 lowtidestart: 360 lowtideend; 735
2014/3/18 12:12:01,    21.31 deg.c,   set temp: 13.10 valvestate: 1 time: 732 lowtidestart: 360 lowtideend; 735
2014/3/18 12:12:04,    21.31 deg.c,   set temp: 13.10 valvestate: 1 time: 732 lowtidestart: 360 lowtideend; 735
2014/3/18 12:12:08,    21.31 deg.c,   set temp: 13.10 valvestate: 1 time: 732 lowtidestart: 360 lowtideend; 735
2014/3/18 12:12:11,    21.31 deg.c,   set temp: 13.10 valvestate: 0 time: 732 lowtidestart: 360 lowtideend; 735
2014/3/18 12:12:14,    21.31 deg.c,   set temp: 13.10 valvestate: 0 time: 732 lowtidestart: 360 lowtideend; 735
2014/3/18 12:12:18,    21.31 deg.c,   set temp: 13.10 valvestate: 0 time: 732 lowtidestart: 360 lowtideend; 735
2014/3/18 12:12:21,    21.31 deg.c,   set temp: 13.10 valvestate: 0 time: 732 lowtidestart: 360 lowtideend; 735
2014/3/18 12:12:24,    21.31 deg.c,   set temp: 13.10 valvestate: 0 time: 732 lowtidestart: 360 lowtideend; 735
2014/3/18 12:12:28,    21.31 deg.c,   set temp: 13.10 valvestate: 0 time: 732 lowtidestart: 360 lowtideend; 735
2014/3/18 12:12:31,    21.31 deg.c,   set temp: 13.10 valvestate: 0 time: 732 lowtidestart: 360 lowtideend; 735
2014/3/18 12:12:34,    21.37 deg.c,   set temp: 13.15 valvestate: 0 time: 732 lowtidestart: 360 lowtideend; 735
2014/3/18 12:12:38,    21.37 deg.c,   set temp: 13.15 valvestate: 0 time: 732 lowtidestart: 360 lowtideend; 735
2014/3/18 12:12:41,    21.31 deg.c,   set temp: 13.15 valvestate: 1 time: 732 lowtidestart: 360 lowtideend; 735
2014/3/18 12:12:44,    21.37 deg.c,   set temp: 13.15 valvestate: 0 time: 732 lowtidestart: 360 lowtideend; 735
2014/3/18 12:12:48,    21.37 deg.c,   set temp: 13.15 valvestate: 0 time: 732 lowtidestart: 360 lowtideend; 735
2014/3/18 12:12:51,    21.31 deg.c,   set temp: 13.15 valvestate: 1 time: 732 lowtidestart: 360 lowtideend; 735
2014/3/18 12:12:54,    21.37 deg.c,   set temp: 13.15 valvestate: 0 time: 732 lowtidestart: 360 lowtideend; 735
2014/3/18 12:12:58,    21.37 deg.c,   set temp: 13.15 valvestate: 0 time: 732 lowtidestart: 360 lowtideend; 735
2014/3/18 12:13:01,    21.37 deg.c,   set temp: 13.15 valvestate: 0 time: 733 lowtidestart: 360 lowtideend; 735
2014/3/18 12:13:04,    21.37 deg.c,   set temp: 13.15 valvestate: 0 time: 733 lowtidestart: 360 lowtideend; 735
2014/3/18 12:13:08,    21.37 deg.c,   set temp: 13.15 valvestate: 1 time: 733 lowtidestart: 360 lowtideend; 735
2014/3/18 12:13:11,    21.37 deg.c,   set temp: 13.15 valvestate: 0 time: 733 lowtidestart: 360 lowtideend; 735


ugghh...

played around bit more , problem solved! of course. valve relay on pin 1, tx pin. every time data printed lcd switching state of pin! using different pin , resolved. feeling rather stupid.

thanks,
nate

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