I wanted to combine the google kit with a relay board to allow voice controlled power outlets on my Pi 3 model B.

Is it possible to use a relay and the google hats at the same time? I can’t find anything on this elsewhere on the internet.


According to the documentation you should be able to add hardware extensions:

This is a hackable project, so we encourage you to make this project your own!

So I had a look and the "hat" (Hardware Attached on Top) seems to occupy all the GPIO pins on the Pi, but there are some exposed on the hat itself:


GPIO Table

From this it looks like you have 4 "driver" pins and 6 "servo" pins that you could use for a relay.

  • Hi Quintin, really appreciate you answer. So it would be ok with a realy board such as this amazon.co.uk/Foxnovo-Channel-Module-Control-Optocoupler/dp/… ? How would power be supplied to the relay? – calmcalmuncle Oct 13 '17 at 19:28
  • Yeah that looks good. You see in the centre of the image there are a bunch of unlabelled pins? If you look at the board labelling the 5v pin is exposed there in red, with ground in black. Then just hook up one of the relay input GPIO's (or several) to a driver or servo pin. The code would be up to you, and I would recommend test the relay apart from the hat first, but it should all work. – Quintin Balsdon Oct 13 '17 at 20:34
  • I just had another look and I think every red square/circle is a 5v pin (definitely next to the servo's) and every black one is definitely ground. It looks like for a relay you would probably want to use the Servo pins, where there is a nice 5v, GND and 6 pins to control up to 6 relays. The driver pins look like they are there to drive motors (they have a +/- for external power to the motors) – Quintin Balsdon Oct 13 '17 at 23:18

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