Level-shifter is absolutely necessary for transitioning between 3.3V to 5V logics. Although there are several pre-built products. I use the circuit: https://www

Level-shifter is absolutely necessary for transitioning between 3.3V to 5V logics. Although there are several pre-built products. I use the circuit: https://www.hobbytronics.co.uk/mosfet-voltage-level-converter https://www.hobbytronics.co.uk/mosfet-voltage-level-converte... when I only need one conversion, e.g. driving WS2812 string from a ESP8266.