the old fogies of the Arduino world, the Uno and Mega, actually have two chips. An ATMega16u2 takes care of the USB connection, while the standard ‘328 or ‘2560 takes care of all ~duino tasks.

It runs on an Arduino MEGA 2560 PRO (or similar microcontroller) and supports a wide array of additional hardware including pressure transducer, water level sensor, flow meter, OLED display ...

If you're still confused about which to pick, here are five use cases when the Arduino microcontroller board ... set of 76 ...