Sorry for the lack of good details. It is a project in the works. Timing and power are not as critical as the "random" flash sequencing. I have any number of power sources to use including 3,9,4.5,12,18, and 24 vdc. Off and On times for the led are at the 3-5 "ons" /second. Would like to have the program pick a random number 3-20 and flash that many times at the 3-5 per second rate and do this every 10-12 seconds or so. The off time between flashes would be the same as the on time at 3-5/sec. I hope this clears some things up. If there is anything else, please let me know as I want to go ahead with this soonest.