However, to fully understand how a neural network (NN) works, [Dimitris Tassopoulos] has stripped the concept down to pretty much the simplest example possible – a 3 input, 1 output network ...

This feature isn’t exclusive to the Leonoardo, as [Michael] explains in a build he sent in – the lowly Arduino Uno can also serve as a USB HID keyboard with just a firmware update.

But even after eliminating the Uno from your selection, you'll still be left with a wide array of Arduino boards to choose ... and three power pins (3.3V, 5V, and VIN). Their onboard LEDs are ...