wpballa1
Posts: 70
Joined: Sat Jun 27, 2015 12:49 am

Fan Power

Mon Nov 18, 2019 5:24 pm

Is there anywhere other than the GPIO pins that could conveniently provide power for a fan for a Raspberry Pi Model 4 B?

trejan
Posts: 1878
Joined: Tue Jul 02, 2019 2:28 pm

Re: Fan Power

Mon Nov 18, 2019 5:30 pm

USB port

wpballa1
Posts: 70
Joined: Sat Jun 27, 2015 12:49 am

Re: Fan Power

Mon Nov 18, 2019 5:34 pm

I need all the available USB ports for other things, I am currently using jumper wires to some of the GPIO power pins and just hoped there was somewhere else on the board I could install a few header pins to free up the GPIO.

trejan
Posts: 1878
Joined: Tue Jul 02, 2019 2:28 pm

Re: Fan Power

Mon Nov 18, 2019 5:39 pm

wpballa1 wrote: just hoped there was somewhere else on the board I could install a few header pins to free up the GPIO.
Solder to the stubs of GPIO header pins on the bottom of the Pi or the test points? Somebody suggested pulling off the plastic frame on the GPIO header so you can solder at the base of the pin on the top side of the Pi and still fit a HAT.

Not many places for easily accessible 5V except for the GPIO header and the USB ports.
Last edited by trejan on Mon Nov 18, 2019 7:40 pm, edited 1 time in total.

W. H. Heydt
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Location: Vallejo, CA (US)

Re: Fan Power

Mon Nov 18, 2019 7:38 pm

wpballa1 wrote:
Mon Nov 18, 2019 5:34 pm
I need all the available USB ports for other things, I am currently using jumper wires to some of the GPIO power pins and just hoped there was somewhere else on the board I could install a few header pins to free up the GPIO.
It's been suggested, and the suggestion was received pretty much as well as it could be. Very unlikely on the Pi4B as trace routing is very tight for space. Still...one may hope that some time in the indefinite future a Pi with a fan header will appear.

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Imperf3kt
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Location: Australia

Re: Fan Power

Mon Nov 18, 2019 8:10 pm

I designed something for this ages ago but that's as far as it went - design.

Basically you get four vertical mount USB male plugs and solder them to perfboard in positions that line up with the Pi usb.
You run some traces through the board to four vertically mounted female usb ports on the other side of the perfboard.
You also run a trace from 5v and ground out to a 2 pin header and done, all without affecting Hats, cases or usb.
You just need to be aware that it uses the 5v from the USB.

Or you could scrap that ghastly idea and just buy a cheap usb hub, pull it apart, and use the 5v from that. Bonus is now you have an additional 3 usb ports.
Or even easier, is to put a male usb plug onto the fan and plug that into the USB hub. You only get two additional ports this way, but ut won't require hacking up the USB hub.

Edits because silly phone auto-incorrect
Last edited by Imperf3kt on Mon Nov 18, 2019 8:18 pm, edited 4 times in total.
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52:4C:52:42:41

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HawaiianPi
Posts: 5718
Joined: Mon Apr 08, 2013 4:53 am
Location: Aloha, Oregon USA

Re: Fan Power

Mon Nov 18, 2019 8:12 pm

wpballa1 wrote:
Mon Nov 18, 2019 5:34 pm
I am currently using jumper wires to some of the GPIO power pins and just hoped there was somewhere else on the board I could install a few header pins to free up the GPIO.
You could solder the jumper wires or a fan header to the GPIO power and ground pins on the bottom of the board. Or you could get a GPIO expansion adapter and use the extra pins on that.
dual_GPIO_expander.jpg
dual_GPIO_expander.jpg (51.49 KiB) Viewed 561 times
https://www.amazon.com/dp/B076SJG1HX
Triple GPIO...
https://www.amazon.com/dp/B07G7SMF3F

Or you could get a Flirc heatsink case and not need a fan at all (won't work with a HAT, though).
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?

LTolledo
Posts: 3322
Joined: Sat Mar 17, 2018 7:29 am
Location: Anime Heartland

Re: Fan Power

Mon Nov 18, 2019 9:42 pm

This is an example for the RPi3B+

this solution is not for the faint hearted..... :D
RPi3B+FanPower.jpg
RPi3B+FanPower.jpg (195.21 KiB) Viewed 528 times
"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!"

wpballa1
Posts: 70
Joined: Sat Jun 27, 2015 12:49 am

Re: Fan Power

Mon Nov 18, 2019 10:26 pm

Thanks for all the suggestions, it looks like soldering to the GPIO back is the way to go for me.

BeauSlim
Posts: 117
Joined: Mon Jul 31, 2017 10:02 am

Re: Fan Power

Tue Nov 19, 2019 6:55 pm

I 3d-printed a plastic bracket that is held underneath the Pi4's GPIO pins with screws. It basically holds a couple solid wires tight to the bottom of a 5V pin and a ground pin while ensuring that the rest of the pins are insulated. The fan's header leads go onto the free ends of the wires. Kind of ghetto, but it works well.

I did this because I didn't want to risk messing up a Pi4, but I've soldered leads to Pi3 and Zero for GPIO, Power and USB. I found it quite easy and I'm still far from being an expert solderer.

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