OK got it working.
/*
* RetirementClock.ino
* countdown the days, hours and minutes till retirement.
*/
#include <Time.h>
#include <Wire.h>
#include <DS1307RTC.h>
#include <Adafruit_MCP23017.h>
#include <Adafruit_RGBLCDShield.h>
Adafruit_RGBLCDShield lcd = Adafruit_RGBLCDShield();
// #defines the backlight color
#define BLUE 0x4
void setup () {
Wire.begin();
Serial.begin(9600);
// set up the LCD's number of rows and columns:
lcd.begin(16, 2);
lcd.setBacklight(BLUE);
lcd.setCursor(0, 0);
setSyncProvider(RTC.get);
}
void loop () {
time_t daysleft,retirementdate;
retirementdate = 1398895200L; // April 30, 2014 @ 22:00:00 hrs.
daysleft = retirementdate - now();
long nineoclock = 75600;
long tenoclock = 79200;
long elevenoclock = 82800;
long twelveoclock = 86399;
lcd.setCursor(0, 0);
lcd.print("Days ");
lcd.print(daysleft / SECS_PER_DAY);
if (elapsedSecsToday(now()) < nineoclock)
{
lcd.setCursor(10, 0);
lcd.print("Hrs ");
printDigits((nineoclock - elapsedSecsToday(now()))/ SECS_PER_HOUR);
}
else if ((elapsedSecsToday(now()) > nineoclock) && (elapsedSecsToday(now()) < tenoclock ))
{
lcd.setCursor(10, 0);
lcd.print("Hrs ");
lcd.print("0");
}
else if ((elapsedSecsToday(now()) > tenoclock) && (elapsedSecsToday(now()) < elevenoclock))
{
lcd.setCursor(10, 0);
lcd.print("Hrs ");
lcd.print("23");
}
else
{
lcd.setCursor(10, 0);
lcd.print("Hrs ");
lcd.print("22");
}
lcd.setCursor(0, 1);
lcd.print("Min ");
printDigits(59 - minute());
lcd.setCursor(7, 1);
lcd.print("Sec ");
printDigits(59 - second());
delay(1000);
}
void printDigits(int digits){
// utility function for digital clock display: prints leading 0
if(digits < 10)
lcd.print('0');
lcd.print(digits);
}
Well it took a few days but it's working so far. It was not easy trying out some of the macros and functions in the time library.
There are two other macros that I'd like to try but I don't understand there syntax, daysToTime_t, makeTime and I haven't found any examples of there use.