Phat Beat - Pins that are free for driving LCD, IR sensor etc

Hi, Building a radio using my pi Zero W. I have a non functioning portable radio which has the speakers and an LCD. The Phat Beat will provide most of the functionality needed - but not all.
Would be helpful to know which of the 40 GPIO pins are actually used by the Phat Beat and which ones are available for other purposes. Can you please share that information?

The Phat Beat will be used for DAC, AMP and perhaps button control - but I also need to attach an IR sensor and an LCD. To get access to the gpio pins for the LCD/IR sensor I am intending to mount a ProtoZero to the Pi Zero W and then mount the Phat Beat to the ProtoZero - that will give me access to the GPIO pins the Phat Beat isn’t using as well as the Power and I2C pins (if your using the pins I would use to drive the LCD I would use an I2C LCD instead) .

as noted in repo:

… well, it details the 28 GPIO, plus the power and ground pins, to be completely accurate.

I am doing the same project and have the same kind of question. According to, the pHat Beat uses pins 20, 25, 30, 34, and 39, all of which are grounds. Does it actually need all these? If so, which grounds go to which parts of the board (there are some features–namely pushbuttons–that I won’t be using)?

On the Pi, all the grounds are common, and linked together. Thats not always possible on a Hat or pHat. Especially if its only a double sided board. You just don’t have the room to run enough tracks to link them all together. Once you plug that Hat or pHat into a Pi though, they all get linked together again and its not an issue.

It’s been my experience that if a ground is listed as in use on GPIO pinout, it is needed for something. I skipped one on my Ledshim and it didn’t work.

In a lot of my projects I mount a Proto Hat or Proto Zero between my Pi and the pHat / Hat. I use a stacking header that is female one side, male on the other end. The proto zero plugs into the Pi Zero and the pHat beat on top of that. It gives you access to all the GPIO pins and grounds all the correct pins on the pHat / Hat.
I have a 90 degree header on my Pi Zero just to make plugging in cables easier. No tight kink in my power supply cable etc. I wanted my own bigger buttons for volume up down etc. There is a pHat Beat under that Proto Zero. My VU meter is viewable from the front through the speaker mesh. It works kind of like a difusser. And you only see it when its on and lit up.

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Well spotted alphanumeric. I’ve never seen this mentioned anywhere else.
I was having problems with my ledshim. It was temperamental on various Pi so I soldered a 2*20 pin strip to some Proto board. I wired up both the 5v & ground and both the I2C wires, but it never worked.
I saw your reply and wired up the ground on pin20 and it worked perfectly.
I never thought about room on the board, I just presumed the grounds were all connected.

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The ones needed / used are usually marked on the pinouts. They can be hard to spot though as they are just black horseshoe shaped blobs.
6 and 20 are marked for the LED Shim
LED SHIM at Raspberry Pi GPIO Pinout