MineSweGamer
Posts: 18
Joined: Thu Mar 22, 2018 9:28 pm

Fan and GPIO header related question

Sat May 25, 2019 8:33 pm

Hi,
Ive been looking if i am able to connect a 40x40x10mm fan for my Pi 3 B+ in my case and the clearance isn't a problem. I was looking at an Noctua NF-A4x10 5V for silent running and it comes with a cable for 2 pin DC running with bare wires in the end. I was planning to connect it to the GPIO as i really don't care about speed control and don't care if it's running 100% all time.

The problem is that i cant seem to find GPIO single pin header connectors for it. Will i be able to Run a 5V Noctua fan from the GPIO and if yes, Where can i find the 1-pin GPIO Headers? I live in Sweden and prefer to order from within the EU to i don't have to struggle with customs.

Thanks in advance.
My Pi: Raspberry Pi 3 Model B+, Samsung Pro Plus MicroSDXC 64GB, KKSB Stainless Metal Case.

dl324
Posts: 122
Joined: Mon May 06, 2019 7:33 pm
Location: Pacific Northwest, USA

Re: Fan and GPIO header related question

Sat May 25, 2019 8:42 pm

MineSweGamer wrote:
Sat May 25, 2019 8:33 pm
The problem is that i cant seem to find GPIO single pin header connectors for it. Will i be able to Run a 5V Noctua fan from the GPIO and if yes, Where can i find the 1-pin GPIO Headers? I live in Sweden and prefer to order from within the EU to i don't have to struggle with customs.
Pi GPIOs are 3.3V and they can't sink or source enough current to run a fan.

You'll need to use a GPIO to drive a transistor with the fan as a high side load. A logic level N channel MOSFET with a current rating high enough for your fan would be easiest.

If you want to be able to control the speed, you could use PWM. You could get the CPU temperature and adjust fan speed accordingly.

MineSweGamer
Posts: 18
Joined: Thu Mar 22, 2018 9:28 pm

Re: Fan and GPIO header related question

Sat May 25, 2019 8:50 pm

dl324 wrote:
Sat May 25, 2019 8:42 pm
MineSweGamer wrote:
Sat May 25, 2019 8:33 pm
The problem is that i cant seem to find GPIO single pin header connectors for it. Will i be able to Run a 5V Noctua fan from the GPIO and if yes, Where can i find the 1-pin GPIO Headers? I live in Sweden and prefer to order from within the EU to i don't have to struggle with customs.
Pi GPIOs are 3.3V and they can't sink or source enough current to run a fan.

You'll need to use a GPIO to drive a transistor with the fan as a high side load. A logic level N channel MOSFET with a current rating high enough for your fan would be easiest.

If you want to be able to control the speed, you could use PWM. You could get the CPU temperature and adjust fan speed accordingly.
You sure? According to the docs, the pi has 5V on Pins 2 and 4 while Pins 1 and 17 are 3.3V. Whats wrong with Pins 2 and 4 for 5V?

Official docs on GPIO https://www.raspberrypi.org/documentation/usage/gpio/
My Pi: Raspberry Pi 3 Model B+, Samsung Pro Plus MicroSDXC 64GB, KKSB Stainless Metal Case.


LTolledo
Posts: 2578
Joined: Sat Mar 17, 2018 7:29 am
Location: Anime Heartland

Re: Fan and GPIO header related question

Sat May 25, 2019 9:30 pm

For a fan that size better split the 5v and Gnd from the microUSB cable and use that to power the fan.
"Don't come to me with 'issues' for I don't know how to deal with those
Come to me with 'problems' and I'll help you find solutions"

Some people be like:
"Help me! Am drowning! But dont you dare touch me nor come near me!"

User avatar
HawaiianPi
Posts: 5199
Joined: Mon Apr 08, 2013 4:53 am
Location: Aloha, Oregon USA

Re: Fan and GPIO header related question

Sat May 25, 2019 9:45 pm

Yes, I use that same fan on a couple of Pi computers I have, including my SSD booted 3B. It works great, even without a heatsink!

Image

I wired a male fan connector to the +5V and Ground on the expansion header, so I could just plug the fan in (other 3 wires are serial GPIO).
Pi_Fan_Serial_GPIO_cable_small.jpg
Pi_Fan_Serial_GPIO_cable_small.jpg (23.13 KiB) Viewed 503 times
MineSweGamer wrote:
Sat May 25, 2019 8:50 pm
You sure? According to the docs, the pi has 5V on Pins 2 and 4 while Pins 1 and 17 are 3.3V. Whats wrong with Pins 2 and 4 for 5V?
Technically, the 5V, 3.3V and ground pins on the expansion header are not GPIO (general purpose input output), since the Pi doesn't read or write data to them. Some people get a bit too pedantic about that.
My mind is like a browser. 27 tabs are open, 9 aren't responding,
lots of pop-ups...and where is that annoying music coming from?

dl324
Posts: 122
Joined: Mon May 06, 2019 7:33 pm
Location: Pacific Northwest, USA

Re: Fan and GPIO header related question

Sun May 26, 2019 12:18 am

MineSweGamer wrote:
Sat May 25, 2019 8:50 pm
You sure? According to the docs, the pi has 5V on Pins 2 and 4 while Pins 1 and 17 are 3.3V. Whats wrong with Pins 2 and 4 for 5V?

Official docs on GPIO https://www.raspberrypi.org/documentation/usage/gpio/
I measured GPIO4-11 when I was experimenting with register access.

The schematic is crap, but it shows VDDIO2_[12] connected to 3.3V. The first GPIO 2 and 3 have pull up resistors to 3.3V.
pigpio.jpg
pigpio.jpg (46.57 KiB) Viewed 466 times
The document you referenced said GPIO are 3.3V:
gpioVoltage.jpg
gpioVoltage.jpg (18.42 KiB) Viewed 459 times

PhatFil
Posts: 1551
Joined: Thu Apr 13, 2017 3:55 pm
Location: Oxford UK

Re: Fan and GPIO header related question

Sun May 26, 2019 12:54 am

you can buy kits of male and female dupont connector kits so you can crimp your own 1,2,3..etc pin male or female cable headers, just search for 'Dupont Kit' and your search engine should give you ebay/amazon etc options..
And youtube should give you lots of hints and tips...

But imho its a lot less time consuming and hassle to buy a few dupont ribbon cables and cut/splice or solder in wires as needed..

I think the key info hinted to above is that the Pi gpio header has 3.3v gpio pins as well as connections to the ground 3.3v and 5v dc power rails. you cant draw more than 12 or 16 ma from a 3.3v gpio pin, But the 5v pin is not as limited.


So your 5v fan can simply be connected to the +5v pin and a ground pin on the gpio header to run at full pelt with power to the pi turned on.

but to have it under gpio control you will need some extra circuitry to limit the 5V supply either by degree or simply on or off.

If quiet and unobtrusive i would probably be happy with it on 100% with pi power ;)

Return to “General discussion”