But what if the Arduino Uno was released in 1980 ... No USB-UART (which also means no USB programming), a different pin layout (Arduino shields likely won’t fit) and more I/Os than the ATmegas ...

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.

Building an Arduino speed detector using IR technology to measure the speed of a moving object is much more cost-effective, and it is also very simple to build. All you need are a few basic parts, ...