Hello i have a question that doesn't have to do with a micro controller. I'm working on a Emergency light project that doesn't require a micro controller. The problem I'm having is how to detect when the power goes out and turn on the lights. The lights are using a Lipo 18650 battery charged by a Tp4056. I'm not sure what to do to detect when the power is out without a micro controller. I'm a little lost can someone please help me?