Adafruit_SHT31 Compatibility MCU Tested Works Doesn't Work Not Tested Notes Atmega328 @ 16MHz X Atmega328 @ 12MHz X Atmega32u4 @ 16MHz X Atmega32u4 @ 8MHz X ESP8266 X Atmega2560 @ 16MHz X ATSAM3X8E X ATSAM21D X ATtiny85 @ 16MHz X ATtiny85 @ 8MHz X ATmega328 @ 16MHz : Arduino UNO, Adafruit Pro Trinket 5V, Adafruit Metro 328, Adafruit Metro Mini ATmega328 @ 12MHz : Adafruit Pro Trinket 3V ATmega32u4 @ 16MHz : Arduino Leonardo, Arduino Micro, Arduino Yun, Teensy 2.0 ATmega32u4 @ 8MHz : Adafruit Flora, Bluefruit Micro ESP8266 : Adafruit Huzzah ATmega2560 @ 16MHz : Arduino Mega ATSAM3X8E : Arduino Due ATSAM21D : Arduino Zero, M0 Pro ATtiny85 @ 16MHz : Adafruit Trinket 5V ATtiny85 @ 8MHz : Adafruit Gemma, Arduino Gemma, Adafruit Trinket 3V