How to interface a 3.3V output to a 5V input. – next-hack.com
Taking It To Another Level: Making 3.3V Speak With 5V | Hackaday
Level shifting 3.3v to 5v only RX and TX pins - General Electronics - Arduino Forum
LM3671 3.3V Buck Converter Breakout - 3.3V Output 600mA Max : ID 2745 : $4.95 : Adafruit Industries, Unique & fun DIY electronics and kits
AMS1117-3.3V Step-Down Power Supply Module DC 4.75V-12V to 3.3V Buck Converter Voltage Linear Regulator 800mA(Pack of 5): Buy Online at Best Price in UAE - Amazon.ae
5V to 3.3V logic level translation/conversion/shifting: how to interface a 5V output to a 3.3V input. – next-hack.com
How to Level Shift 5V to 3.3V | Random Nerd Tutorials