Blinking LED quits working.

Using Arduino Programming Questions
1

This is a simple code which can probably be done a better way. The problem I am having is after some time the LED quites blinking, can anyone tell me why or maybe a better way to do this. The led is just to let me know the clock is working as it blink once per minute. Thanks

#include <Wire.h>
#include "RTClib.h"
#define clockAlarm 5 // Relay Output
#define ledIndicator 7 // LED Output
int hour1;
int minute1;
int year1;
int month1;
int day1;
int second1;
int runOnce = 0;
int ledEarlier =0;
RTC_DS1307 RTC;

void setup ()
{
Wire.begin();
RTC.begin();
pinMode (clockAlarm, OUTPUT); // set output 5
pinMode ( ledIndicator, OUTPUT); // set output 7
}

void loop () {
DateTime now = RTC.now();
hour1 = (now.hour());
minute1 = (now.minute());
second1 = (now.second());

if (now.minute() > ledEarlier)
{
ledEarlier = now.minute();
digitalWrite(ledIndicator, HIGH); // turn on led
delay(100);
digitalWrite(ledIndicator, LOW); // turn off led
}
else if (hour1 == 6 && minute1 == 55)
{
if(runOnce == 0)
{
digitalWrite(clockAlarm, HIGH); // activate alarm relay
delay(3000);
digitalWrite(clockAlarm, LOW); // activate alarm relay
runOnce = 1;
}
}
else
{
runOnce = 0;
}
delay(1000);
}

2

Pabble:
if (now.minute() > ledEarlier)
{
ledEarlier = now.minute();

The problem is this part. After minute rolls over, it's not going to be bigger than ledEarlier anymore.

Say you start the sketch and the led blinks at 1:59. One minute later, it's 2:00. Now minute is 0 and ledEarlier is 59. So the if statement is now false all the time since minute will never be more than 59.

3

Thanks, that makes perfect sense, that would explain it working for quite awhile before quiting sometimes. That never occurred to me, duh :slight_smile:

4

Since time only marches forward and as of yet no one knows how to make it go backwards, you could instead ask:

if (now.minute() != ledEarlier)
{

Since ledEarlier is always in the past, then anytime now is different, it must also be greater.

5

Very good thanks, I will try that. BTW I am new to this stuff but trying to learn, I will have to remember to use not equal to in the future.