2-mic and 4-mic linear array GPIO pins

Hi there,



could you please provie the GPIO connection pin layout for the 2-mic and 4-mic linear array hats? I would like to see which GPIO pins of the raspberry are unused so I can use them for other things.



Thanks in advance!

Hi there,



For 2 mic, please refer to <LINK_TEXT text=“https://github.com/SeeedDocument/MIC_HA … AT_SCH.pdf”>https://github.com/SeeedDocument/MIC_HATv1.0_for_raspberrypi/raw/master/src/ReSpeaker%202-Mics%20Pi%20HAT_SCH.pdf</LINK_TEXT>



For 4-mic linear array hats, please refer to below.







cheers

Bill

I’d also like to use unused GPIO pins on the 2-mic.

According to that “Respeaker 2-Mics Pi Hat” (2017/8/16 8:42) pdf the following are not connected:

GPIO4

GPIO5

GPIO6

GPIO7

GPIO8

GPIO9

GPIO16

GPIO22

GPIO23

GPIO24

GPIO25

GPIO26

GPIO27



GPIO01 is missing from the pdf but this pinout https://pinout.xyz indicates that GPIO1 is “ID_SC” (on pin 28)



I just thought I’d list the apparently unconnected GPIO pins in case anyone else has the same problem.



My question is really though, what’s the intended method to access these unused (if they really are) GPIO pins? Solder a wire to the stub of GPIO pin header that pokes through the top of the Respeaker 2-mic board? Replace the female GPIO pin header on the Respeaker 2-mic with some kind of special GPIO header with female on one side and extra long male on the other to stick out the other side of the board (I have not seen any part like that unfortunately)?



Any advice on how people might connect to these free pins? And, are they actually free to use or are there some subtle/obscure Pi Hat rules that prevent them from being accessed when a Hat is on (like the Respeaker)?



Too bad there’s not just some kind of breakout header/connector on the Respeaker 2-mic to access all the unused GPIO pins.





Respeaker 2-Mics Pi Hat

attachment=0]Screen Shot 2019-04-03 at 23.41.55.png[/attachment]
Screen Shot 2019-04-03 at 23.41.55.png


Thanks!


Soooooo… yeah. This can be a bit difficult.

If you want to use multiple official HATs then they cannot stack by definition. There is no wiggle room due to how the EEPROM is expected to work. It seems that stacking HATs was not really something they were concerned about when creating the standard. However, if one or more of the devices do not follow this standard you could potentially stack them.

Why do I bring up two HATs? It’s the cleanest and easiest solution, IMO.

What I recommend, is to try using a proto-HAT, similar to this: <LINK_TEXT text=“https://www.seeedstudio.com/Raspberry-P … -2410.html”>https://www.seeedstudio.com/Raspberry-Pi-Breakout-Board-v1-0-p-2410.html</LINK_TEXT>.

You can then plug a HAT on top of this, and thus be running two “HATs”, the Mic Array that you want to use, and then whatever you build on the unused pins.

Alternatively, you can solder onto the exposed pins on top. This is the quickest way to achieve your goal, but messy and could destroy the HAT you have. I do not recommend this unless you have a fair bit of experience soldering. The previous method I mentioned is more organized and lets you double check your connections much easier… I am accident prone though, so maybe I’m just paranoid. :wink:



Hope this helps!