I want to build something very low power with bare MCU, something like in this tutorial: http://interface.khm.de/index.php/lab/experiments/sleep_watchdog_battery/
I plan to use 9V or 12V battery. 7805 regulator is not an option because it draws too much current. Should I use some other regulator?
Is it possible to use simple voltage divider made from two resistors?
Thanks in advance!