Meet the Tethercell Smart Battery Adapter: a handy tool that makes your regular AA batteries smart. It lets you turn AA-battery powered devices on / off from your smartphone. You can also put your devices on a schedule. You get an alert when batteries are running low on juice.
Tethercell has a range of up to 100 feet. You will only need on Tethercell adapter per device to get started. Costs under $30 at this time.