Logic Level Converter - KeirRice/PolarTable GitHub Wiki
Logic Level Converter
We can build a circuit to do a bi-directional shift of voltages to bridge between a 3.3V and 5V circuits.
This can be done using a couple of MOS-FET N Channel Enhanced Transistors like the 2N7000 or BSS138
You can also buy pre-made breakout boards that do this for you, like this on from Sparkfun.