We're running a Raspberry Pi 2 B as a Tomcat-Server and meanwhile it became quite warm so I'm thinking of using one of the old CPU-Fans (12V) we're having around.

Unfortunately I couldn't find any proper documentation how to do it with my Raspberry. For the first model I could find some useful information which referred to the usage of holes close to a capacitor. The black and the red cable should be used, the white one removed.

On my model I couldn't find them, just "run" holes, but according to the information available online those have a different purpose..

Run Pins

Some other sources refer to the usage of the GPIO-Port, but so far I have no idea what to do with my Germany-coloured cable. Should I just cut off the yellow line?

And is it safe to use it? And which Ports should be used? One fella here seemed to have used a 14V pin and his Pi died: How to connect a 12V fan sensor wire to the Pi

What would you recommend me to do?

12V Germany-Coloured fan

  • Unless you are overclocking there is no possibility of the pi becoming too warm -- however, if it comforts you psychologically to use a fan, feel free. You do not refer to having checked the CPU temp. Have you bothered? Do you know how to do so?
    – goldilocks
    Oct 23 '15 at 10:48
  • Raspbrery is one spelling I have never seen before! I have seen Raspberri, Rasbery, Raspbery and others, but I have never seen this one! :-)
    – user72982
    Dec 14 '17 at 7:29

I doubt you can power the fan from the Pi. The Pi only has 5V and 3V3 rails. You could try connecting to a ground and 5V pin but I doubt anything would happen.

So you will probably need an external 12V power supply.

There is no point connecting the yellow wire. It tells you the RPM (two pulses per revolution). The fan will be running full speed as long as power is applied.

The run pads are to reset the Pi. Nothing to do with a fan.

See http://pcbheaven.com/wikipages/How_PC_Fans_Work/

  • Alright, so I'll try 5V and see what's going to happen. Stupid beginner-question: How?
    – Qohelet
    Oct 23 '15 at 10:17
  • And - which colour of the cable goes on which pin? Is it possible to break something by doing it?
    – Qohelet
    Oct 23 '15 at 10:37
  • Fairly conventionally black is ground and red is the power line. Have a look at pi.gadgetoid.com/pinout. You will damage a GPIO if you connect one wire to 5V and the other to a GPIO. Don't get paranoid but do practice double checking. It's probably safest to make the connections with the Pi unpowered. Use pin 4 for 5V and pin 6 for ground.
    – joan
    Oct 23 '15 at 10:44

I realize this is well past its date, but your really better off with a 3.3v or 5v fan rather than trying to recycle an old case fan.

Even if the fan's power needs were more of a match, the larger fans require more torque to spin the blades and that will draw more current. 40mm 3.3v or 5v fans are a good soft limit for trying to power from the RPi itself.

I give you full props for trying to up-cycle that old computer case fan, but it really isn't a good fit here due to the limits of the RPi power supply.

A quick google search will find a number of inexpensive 40mm 3.3v fans out there. There are even some specifically designed with mounts for use with RPis.

As for how to do it: take two male-to-female jumper wires color matched to the wires on the fan cord (ignoring the yellow wire) and then plug the male end of the jumper into the fan's socket. Then take the female end of the jumpers and plug the red one into pin 2 and the black one in pin 6 of the GPIO as shown in this diagram.

Taken from the Raspberry Pi 7" Screen setup instructions

The image here is cropped from the instructions for powering the Raspberry Pi 7" touchscreen, but it will work for powering fans or anything else that just wants 3.3VDC power.

  • Thank you for still answering =) - the basic intention of that little project was to use some of the piling fans we still had lying around. Our Pi was not overheating so much that it's been necessary to cool it down - it would just have been a cool idea
    – Qohelet
    Mar 13 '17 at 10:02

You can use a 12 volt fan, it will just run slower. The red should be power, the yellow is for sensing the fan rpm (for which you'd need additional circuitry). You should be able to pop the pins out of the connector and arrange them appropriately. I recommend Delta, Nidec, or Panaflo fans.

  • 1
    There are at least 12V fans out there that do not run reliably at 5V, they simply do not start to turn. Some do, other don't.
    – Ghanima
    Apr 13 '16 at 6:37

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