The new Raspberry Pi Model B+ may not have a faster processor or more memory than the original Raspberry Pi mini-computers that launched 2 years ago. But it has twice as many USB ports, more GPIO pins, lower power consumption, and other improvements.
It can also wear a HAT… which is a new type of add-on hardware board designed to work with a Raspberry Pi.
While there are plenty of hardware boards that you can attach to the 26-pin connector of the original Raspberry Pi Model B, the older version of the single-board computer doesn’t automatically detect whether an add-on board is connected or not and software drivers usually just assume it is… even if it’s not.
So the team designed the Model B+ to work with a new type of board called a HAT or Hardware Attached on Top. A Raspberry Pi Model B+ can automatically detect when a HAT is connected so it can make use of the 40-pin GPIO connector accordingly.
Boards built for the original 26-pin connector will continue to work with the Model B+ but they don’t function as HAT boards.