I was curious if there is anyway to have solar powered timer that displays up to 13 digits counting down in seconds.
something similar to the solar powered calculators used in elementary schools?
I basically want to make a death watch however I'm not really sure what I could use to minimize power consumption.
It needs to show 13 digits (10 are numbers and 3 are commas).
I would like for the battery to last 3-6 months if possible.
10 digits, counting down in seconds, is about 320 years. You probably should not count on any technology working that long.
What is the long term plan for changing the batteries and restarting the countdown?
jremington:
13 digits, counting down in seconds, is about 320,000 years.Is there a long term plan for changing the batteries?
I assumed the first digits would be days. 50(days),24(hours),00(min),00(sec). But that's only 8 digits + 3 commas. Maybe years too?
Curious as to who, or what, is dying though.
DangerToMyself:
Curious as to who, or what, is dying though.
Everyone is. 
It's from a Hollywood movie, can't remember the name.
With serially-addressed display drivers you can use as many digits as you want. (Start with one digit and work your way up.)
A count-down timer is simple, and you might by using the serial monitor (so you can start experimenting/programming without a display or any additional hardware).
panel should have a voltage rating, plus a current/and/or power rating. If they don't give you all 3 numbers, Power (Watts) = Volts x Amps. Of course the solar panels specs are likely optimistic.... at
something similar to the solar powered calculators used in elementary schools?
You'll need a bigger solar panel and it will depend on the current requirements for your display. The solar noon with clear skies, in the summer, on the equator. 
You can estimate the current requirements for your project, then measure the current once it's built.
I would like for the battery to last 3-6 months if possible.
Check the milliamp-hour rating on the battery compared to current requirements of your project.
With solar recharging the battery only has however long you expect to go without sun.
You'll need quite a bit more (short-term) power from the solar panel than the Arduino/display requires because you could be charging the battery for 1 day or less and then discharg for a few days. ...It's a statistical game.
If you need accurate time over months, you'll need a real-time-clock module (RTC) because the oscillator built-into the Arduino is not accurate. The RTC won't be perfect either... No clock is perfect, so check the specs to see if it's accurate enough for you. If not, you'll need a cell-phone, Internet, or GPS connection to get the "true-time".[/quote]
I'm counting in seconds.
I have roughly 2,000,000,000 seconds left to live wanted to build a watch that has a long battery life that can rely on light to re-charge itself (similar to the old school cheap calculators).
I just need it to keep track of time doesn't need to be extremely accurate.
I have roughly 2,000,000,000 seconds left to live
Are those 62.4 years guaranteed, or will you still have to look both ways when crossing the street?
seconds assume you're living a minimal risk lifestyle.
emsjvh:
I'm counting in seconds.I have roughly 2,000,000,000 seconds left to live
Just the project every well-adjusted person needs. ........
Still, using an arduino might mean that a boogieman shock detector could be incorporated, along with RTC and logger to say when, and all the appropriate calculations made on board. No need to transfer to Excel though.
Hi,
Like this, a film called OTHERLIFE.
Filmed in Perth, WA, Australia, it hasn't been out long, released 17th Oct 2017.
google countdown clock movie
Some other references, but I looked in image search.
You could use these 8x8 with their MAX7219 IC, daisy chained, and use LEDs as your delimiters
You could space the arrays to fit the LEDs.
And a RED filter.
Tom.....
A better solution is to write down the current day and current time based on maybe a usa atomic clock. And then .... on the day you die.... ask your doctor or relatives to record the time when the doctor says 'certify'. Then use an online calculator to estimate the time difference in seconds. This is all assuming you stage-left or make your exit in this general way. But ... as forrest gump says... life is like a box of chocolates...
