Connecting fan to brewpi photon

I saw this post: Connecting fan directly to Arduino

And I understand the wiring, but not sure about the layout on the brewpi photon. As I understand, there are 4 Digital Outputs you can hook up to with the green plugs. Each supports a 5v, 20mA +/- wire. Live wire to the +, grnd to the -.

But for the PWM fan, I also need the VIN. I’ll be using external 12V power so the VIN should have sufficient supply.

I think I found the solution. I was thinking along these lines, but it seemed odd.

So, you connect the 12V & GRND via the RJ12 jack then connect the 5V to the + on one of the Digital Outputs.

I’ll give thi a shot tomorrow…looks like I’ll be dusting off that old crimp tool.

Well, connected it up like above and set it to a manual actuator. Fan’s not toggling on though.

I had to remove and then re-add all the devices to get the fan running manually.

hey guys,

I have a 12V DC fan with 2 wires that I would like to use as a chamber fan.
When my Brewpi was in Test mode, i connected the two wires to the + & - pins on one of the the digital outputs (in the green block) when i switched that output on with the touch screen the fan worked fine.

Now I have the Fridge and brewpi connected and ready to go ,everything is working fine but the fan does not seem to work.

Is it possible to have the fan run constantly off one of the 4 digital outputs?


You cannot connect a 12V DC fan to the outputs directly. The outputs are only 5V and cannot deliver much current (20mA).

You would need to get a fan with a PWM input or switch the fan with a transistor or DC SSR (

But I would just let the fan run continuously on low speed instead of switching it. Find a power supply that gives you the right speed and just connect it without the BrewPi.