You don't download Adafruit_I2CDevice.h alone. You install Adafruit BusIO via the Library Manager.
Adafruit_I2CDevice.h <-- This is the file you wanted! Adafruit_SPIDevice.h Adafruit_BusIO_Register.h Once installed, using the library makes your code incredibly elegant. Here is how you would talk to a BMP280 sensor (address 0x77 ): adafruit_i2cdevice h library download
If you’ve ever tried to write a driver for a custom I2C sensor (like a barometer, OLED display, or magnetometer), you know the headache of managing Wire.beginTransmission() , Wire.write() , and Wire.endTransmission() over and over again. You don't download Adafruit_I2CDevice