I want to build a little box with a timer that runs a fan for a few hours and then shuts off. I'll be using a 120mm computer case fan at something between 7-12V...right now, I can run it off a 9V battery but they don't have a ton of stored energy and I have to remember to turn it off. My design will probably use 6 AA/AAA batteries to spin the fan at a medium speed (although this might be too much voltage for the timer circuit). I need to design a circuit that will use some sort of timer chip to run it for an arbitrary amount of time (6-12 hours...doesn't even need to be adjustable) and then shut off. I am comfortable soldering and reading circuit diagrams but I am not familiar with the sort of ICs that do this. I've used 555 timers but I don't think they are right for this situation. Anyone have any IC/circuit suggestions? Know any other good forums where I could pose this question?