Whenever your system wakes from sleep, the OS X Kernel will output a small code to the system console that indicates the reason for the wake event. Since you can access the system console using Apple's Console utility, if your system is regularly waking up when you have put it to sleep, then you can help track down the reason using these codes.
To locate these codes, first open the Console program. Next, select "All Messages" in the sidebar, which will bring up the output from active and ongoing system events. Now enter the term "wake&… Read more