long countdown timer, how to save power?

[ardhuru]

Easiest thing in my mind is to get an 8pin RTC, DS1602 type and use that. Then you can put the PIC to sleep and have it wake itself up every roughly XX number of seconds using the WDT timer and the WDT prescaler.

I think this is absolutely the easiest, perhaps the most accurate way of doing it too, especially since you need the LCD to light up only on manual intervention. I have not used the DS1602, but I have used the Philips PCF 8563, and the current draw is almost immeasurable.

Regards,

Anand