+------------+ +---+ Button +---+ | +------------+ | +--------+ | +----+ +---------+ | | | | | | | | | µ | | | | | w/RTC +--+ | | | | | | ++----+----+ | | | | | | | | | | | +-+-+ | | | |LED| | | | +-+-+ +----+ | | +------+-----+ Battery