New project but similar question. If I supply 5V to the 5V pin, does that get regulated to 3.3 on the 3v3 pin?
To test my hypothesis. I plugged a usb cable into the wemos D1-mini and with a DMM, checked the voltage at the 3v3 pin. Yep, 3.29 So it would be safe to say that I can use the 3.3v to run my 3v I2C sensor?