I'm running off batteries so I don't want to leave the esp8266 on unless there is a state change. I have the button hooked to +3.3v that triggers the reset pin on the esp8266 which then sends the data off. This works fine but I would like to use 3+ buttons and I need to know which button was pressed. Since the esp8266 is just being reset there is no way to tell which button reset it so I was thinking of hooking each button up to a RC delay circuit to keep it's state longer so the MC can then boot up and read it. Using this formula
$$t = -\log \left( \frac{V-Vc}{V} \right) \times RC$$
I should be able to keep the buttons in the correct state long enough for the MC to boot and read the values while not using a lot of energy.
Is there a better approach, easier?