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.

raspberry pi hat

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.

You can find more details about HATs at the Raspberry Pi website or check out hte specifications at github.

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3 replies on “Raspberry Pi Model B+ can wear HATs (Hardware Attached on Top)”

    1. humorous answer:
      This isn’t TF2, in fact not a single letter or number to spell TF2 is found in “Raspberry Pi Model B+” so why would you even asume you could?

      serious answer:
      You can’t stack HATs. While stackable HATs were part of the specification discussion, the concept was eventually thrown out due to the large increase in complexity of autoconfig and potential for user error.
      You can however design non-HAT stacking boards using the example surface-mount connector scheme.

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