Sorry if that me appear a bit vague, but while testing on a breadboard i found out that 5v is available on the V in pin when powered from a PC via USB.
I have been using this to power some extra circuitry that needs 5v, there is enough current available to power a 16 by 2 line I2C LCD with backlight.
Is this okay to use for experimental use, much simpler than separate supply when interfacing to other hardware. I have been running multiple examples from some previous Arduino code and hardware, porting them across with a lot of help from the Forum using code snippets that people post.
I can now get a few sensor devices running on the core, such as a mpu 9250, ( sending Pitch/ Roll ), a Sharp dust sensor, sending data to a connected LCD, and also got a ST7735 colour graphics LCD working, receiving text & sensor values. this is all thanks to the forum members who are very helpful and willing to share their knowledge, so thanks to all of the contributors to the forum.
i am happy to provide whatever code i have up to now if anyone wants it, but i am very new to this type of forum, so not sure how to post any example code, but will try if anyone interested.