I am trying to use HC-05 (5V, onboard regulator levelling to 3.3v) with Arduino Pro Mini (3.3v) but I have had little success.
I am using a coin cell to power the pro mini which powers it on and is working fine.
But, my HC-05 doesn’t power on. I am trying to power it externally using two 3.7v Lipo-batteries that gives a total of 7.4v but I have tried numerous changes and nothing seems to work.
Circuit Diagram and HC-05 image attached below.