HC-05 Bluetooth RX requires 3.3 v (TX has a regulator built in) I understand my uno and nano are 5v Ive connected a 3.3v Zennor in series with a led and resistor and with multimeter established the black stripe goes ground to achieve 3v But which is considered ground between hc-05 RX or the arduino TX that it connects to.. Is this an acceptable way to drop the voltage? If not I've ordered some small voltage regulators. But I still have the same question, which way round. The regulator has connections v1...gnd...vo Thanks Paul (Edit to this post) Ive read a bit more and if correct I now think the Hc-05 rx connects direct with the arduino tx and the Zennor connect anode to the link and stripe side to ground... Still unsure..