What do O-Rings Do on a Mechanical Keyboard? In this video, Betty from Switch and Click goes over what O-rings do to your ...

The ports and the switches on the back of the iRig I/O 49 cover all the bases, too. There's a toggle for USB power, a DC port, and then a Mini-DIN MIDI port for the included USB or lightning ...

The MelGeek O2 is a low-profile mechanical keyboard that manages to stick the landing when it comes to user experience for Mac users — at least from a hardware perspective.

That sentence you mentioned continues with “Connect each row and column of your keyboard matrix to a GPIO pin, and define it in config.h.”. This specific matrix is 8 columns x 5 rows.