I am planning to do the same thing, so I ask: in the end did you use the 5V pin or the USBVCC pin, or something else?
That covers the Mini, I guess, but in the case of the UNO, it is recommended to not supply 5V power via the 5V pins because it can damage the board. I read that here, about half-way down the page:-Arduino UNO & Genuino UNOThanks for the link and here's what it says:"5V. This pin outputs a regulated 5V from the regulator on the board. The board can be supplied with power either from the DC power jack (7 - 12V), the USB connector (5V), or the VIN pin of the board (7-12V). Supplying voltage via the 5V or 3.3V pins bypasses the regulator, and can damage your board. We don't advise it."That's pretty vague. They don't say how it could damage the board or what part of the board it could damage. I wonder if they mean applying a voltage to the output pin of the regulator can damage the regulator. I am still just as confused as before...
Nothing else added, nothing connected to Raw.
You're right, I was thinking of the UNO. My bad. That means the on-board 5V regulator has no input voltage so there is no conflict since the on-board regulator is not running.
Older 78xx/LM317 type regulators had an internal diode across in/out.
As far as I can tell, some 1117 regulators don't mind it, while others will fail if you do that
PROTECTION DIODESUnder normal operation, the LM1117-N regulators do not need any protection diode. With the adjustable device,the internal resistance between the adjust and output terminals limits the current. No diode is needed to divertthe current around the regulator even with capacitor on the adjust terminal. The adjust pin can take a transientsignal of ±25V with respect to the output voltage without damaging the device.When a output capacitor is connected to a regulator and the input is shorted to ground, the output capacitor willdischarge into the output of the regulator. The discharge current depends on the value of the capacitor, theoutput voltage of the regulator, and rate of decrease of VIN. In the LM1117-N regulators, the internal diodebetween the output and input pins can withstand microsecond surge currents of 10A to 20A. With an extremelylarge output capacitor (≥1000 μF), and with input instantaneously shorted to ground, the regulator could bedamaged.