FanShim - more complete pinout?

This is more of a nitpick on documentation and with the hope that someone like me doesn’t need to scratch my head.

  1. The pinout page is nice but I am pretty sure you are using 5V and ground but you don’t say which (or all?) I think that would be nice to know.

  2. it would be nice to have a detailed list of what the supposed usage of each pin would be. Granted this device is very simple, but details are important if you want to combine this with other shims/hats.

  3. Is, was there some though on how to attach the to screw hole with standoffs? There is no “standard distance” between stackable boards but perhaps you could come up with a part kit that has three long threaded standoffs with maybe a small spacer to keep the Fanshim stable while screwing a hat on top. Its a detail thing.

The pins shown in use are pretty self explanatory but what is the wake pin doing? I only ask because I need that pin for another hat and I was thinking of taking out this hole but just looking at the provided documentation , i don’t know what it does.

Anyways, I will stop bellyaching. Its a good product, but in my experience with documentation , devil is in the details.


Yeah, something is not right with that pinout? Its showing Pin 39 (ground) as being used but the Fan Shim doesn’t connect to that Pin?
That being said, in the grand scheme of things, what pins the Fan Shim uses for +5V and ground won’t affect you being able to reuse those pins for other hardware. All the ground pins on the GPIO are wired together as a common ground. Pins 2 and 4 the +5V pins are wired together too. The Pinout should be updated anyway IMHO though.
On to the wake pin. If you shut down your raspberry Pi, and leave it powered. Momentarily grounding GPIO 3 will boot / wake it up. Pushing the button on the fan shim will ground GPIO 3 / pin 5 while its pressed, and boot up your Pi if it has power. It can also do a proper shut down with a config.txt edit.
If you don’t ever press the button on the fan shim there is no need to worry about the wake pin. And as far as I know, i2c will still work. You can use i2c and the shut down function of GPIO 3. You will likely get an io error if your using i2c, but the Pi is going to shut down anyway.

Awesome, thanks for the complete reply. Still it would be nice to see on the web page wake - > connects to pull down (?) through switch to ground…or something.
Again, its a simple device.


I agree, the write up could be a bit more detailed. There is a bit of info in the readme.

The pin marked Button in the pinout, is the one, I believe is polled by the python code in the examples.
If you “don’t” make the config.txt edit. dtoverlay=gpio-shutdown. grounding GPIO 3 “won’t” do the shutdown. I did the edit as thats what I want to happen. I would have to undo that edit to do the fancy button stuff like detecting a long press etc.