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Take a look at this.
The LEDs and ICs would be a little more but we might be able to shop around.
You might be able to eliminate the switch to make up for it if you pot it the night before. http://www.discovercircuits.com/H-Corner/lowpwrflasher.htm
The schem says 4ua average current, if it is that low you probably wouldnt need a power switch the led would flash for 4 years, pretty much the shelf life of the battery.
I have learned from somewhere that a light duration less than 30ms appears to be dimmed which is why PWM is used as a light dimmer. Therefore the duration should be 30ms, not 10ms.
I think the average current was calculated to be too low. If the LED is turned on at 1mA for 30ms and it blinks each 500ms (2 blinks per second) then the average current is (30/500) x 1mA= 60uA. The 240mAh battery will last for 4000 hours (5.5 months) but the LED will be dimming each month. But I think an LED is not bright enough at 1mA unless it is simply an indicator. Is 2 blinks per second fast enough?
The shelf life of a Lithium battery exceeds 10 years. I have the Li-Ion battery from my daughter's first cell phone. It is still charged and has lots of power. It is about 16 years old.
Ordinary alkaline batteries have a guaranteed shelf life of 10 years today.
Yes, I think your right on the on time. 30 ms would appear brighter.
His calculation was .5 Hz. (2 seconds), but I was thinking maybe 4 LEDs pointing out from the puck at 90 degree angles at 1 second for each set of 2. They would then be kind of random due to component variances. (say red and green - like Christmas) Since he only needs say 80 hours we could raise the current quite a bit.
The super bright LEDs are amazing... Five or 10 times brighter than the cheap ones!
Some super-bright LEDs are simply an ordinary old dim LED in a package that focusses the beam into a narrow angle. The new surface-mount LEDs are very bright over a wide angle.
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