Sorry for the disappearing act, I was otherwise engaged.
So I'm using 3x AAs which provide 4.5 volts, more than enough to do the job. The way I have it configured now, 10x LEDs light up for 1 minute in their random configuration. When increasing or decreasing the total number of LEDs, one LED illuminates for 500ms.
The big picture project is to build a modular deck holder for the Dominion game to hold all the cards for all the random expansions, and based on the number of decks, (which is changed by adjusting the "max" number of leds using +/- buttons in the diagram below) randomly select 10 decks and display those lights on for 60 seconds, allowing you to pull the decks out of the box.
So now I have the electronics but, I actually need to build the holder. With even as little as 3 hours of functional power, that means over 180 randoms +/-. I doubt I will play 180 games in a year, so it meets my needs. Also, I am only outputting at 20 out of 255, so I'm assuming the reduced brightness will also prolong the battery. I'm fairly confident that 3AA should last me one or more years assuming the batteries are not hot garbage. With rechargeable, the brightness may be lower but still good.
And to answer questions, ref: limitations, obviously has to be portable, and I want the batteries to be easily replaceable.
I'm fairly confident that the current setup and code work to my requirements.
Cross posted from my other thread:
Imagine the black bars being full slots in a holder, and the white bars being empty slots, that could be filled.
[+] increases the length of the strip flashing the next light in the strip to show where the "max" is at for the random (green dot in this case).
[-] decreases the length of the strip as per above.
[rnd] lights up 10x random "full" slots (cyan dots as an example) for 1 minute. If you press the button again, it lights up a new random 10 lights for 1 minute.