clarification on executing next OneTime measurment and getting delay time about bh1750

[nekitoss]

Another idea is to create startOneTimeMeasure(), which will just start measure using already set (with validation) ONE_TIME mode, and, unlike conigure(), it won't be waiting 10ms to sensor receive command (if i understood corretly that delay in case someone tries to do something just right after), which will allow non-blocking flow

[coelner]

I think this library will not get any further attention, maybe you should consider to fork and patch.

The sleep in general is not the problem, but most of the arduino devices doesn't restore their RAM. therefore the library needs to get initialized after every wakepup.
However, the instance of this library stores the last value and no, there is no getter for this currently:

BH1750/src/BH1750.h

Line 81 in b6986b5

unsigned long lastReadTimestamp;

this here:

BH1750/src/BH1750.cpp

Line 102 in b6986b5

// Wait a few moments to wake up

is because of the behavior of this chip, AFAIK it needs this time by itself. This value seems to work for most of the users, but feel free to look here: https://github.com/Starmbi/hp_BH1750/wiki/

As far as I remember you should be able to trigger a OneTime command, got to sleep the right amount of time and read then the sensor. The sensor itself stores the last measurement in the register until a new measurement is completed. (Need confirmation).
A get function for the wait delay could be useful, but is unlikely to happen.
On a battery driven design, you could sleep long enough to be sure that this chip is ready to deliver a new value (e.g. 500ms). If you want both, like maximum battery saving AND fastest refresh rate on hard timings, then this library is not useful.