Sorry if this question comes up a lot, but I am new to EEVblog and didn't really find the right solution when using the search capabilities.
My background is as a Software Engineer, and only just getting started in electronics. For my first project, I want it to run on battery power, include an MCU (probably some ESP32 variety), have a soft latching switch for power on and power off, but also have the capability for the ESP32 to timeout and power off.
I have watched Dave's video, EEVblog #262 - World's Simplest Soft Latching Power Switch Circuit, several times and understand it to the best of my ability at the moment.
This circuit gets me 66% there. How can it be modified to also allow the MCU to power off? Note that I have seen videos from other channels that have a soft on, and timeout off, but I really would like a power off on button press option.
My instinct is to add another NPN BJT with an output pin from the MCU connected to the base via resistor, emitter connected to ground, and collector connected to the collector of the right most BJT in his schematic.
Another newbie question, what software is best for a beginner to use to draw schematics? Preferably offline and for Ubuntu. (Links to any relevant EEVblog posts are welcome).
Thanks.
Dave.