Moteino M0 periodic sleep using RTCZero library

[moallen]

Am I correct in thinking there isn't a way to shut the onboard +3.3 LDO regulated voltage down on a Moteino M0 using the RTCZero library? In other words, anything getting its power from there, like a BME280 sensor, is going to stayed powered up and drawing current. I guess the solution is to supply 3.3V to such a sensor or a display from another source and somehow turn it on and off with a Moteino gpio pin?

[Felix]

The M0 is a general purpose dev board.
It was designed to be able to put it to low power sleep, at under 10uA.
Most sensors like the BME280 have a low power mode as well, at under 1uA or around that. So for such sensors you need to put them to sleep through library commands or programming the sleep commands in their registers, then waking them up briefly when you need a reading.

To completely cut power off to something before sleeping the MCU, you need to do that through a power circuit, could be different in each case but for simple DC circuits it can be done with a mosfet frontrolled from a MCU GPIO.