Pi3 Fan connection options

[SteveSpencer]

[Originally mis-posted in beginners, sorry!]

I would like my Pi 3 in a case. I also want it cool, so want to put a 5v fan mounted over the SOC. (Should airflow be away from the SOC, or towards it?)
However, I also want to (a) not modify the board in any way and (b) be able to use 40-pin IDC connectors with the board.

Most case/fan combinations I have seen simply plug onto the GPIO connector. What, if any, are the alternatives, bearing in mind my two constraints?

One approach I have thought about is to take an "extra tall" header, and solder the fan connectors to it, which should allow me to connect a cable to the header pins as well.
An alternative would be to tap the 5v via a micro USB plug/socket arrangement, I suppose..

[MarkHaysHarris777]

Have you fan power pins piggy back on whatever you have plugged into the 40 pin header. Your idea of tall header extenders is good. If you are careful, it is possible to solder a small wire-wrap at the base of either 5v pin; use a small gauge enamel insulated copper wire normally used for magnet windings--works well.

I build a speed controller for mine using ULN2803 (controls all three PIs) using pwm pin on each PI. (totally optional)

It is always better to pull the air into the case and blow it out the top. Mount the fan above the SoC heatsink and have the fan exhaust the warm air up away from the SoC and out the top. Make sure there is enough of a vent for fresh air to come in. Most of these small 5v fans are capable of moving up to 5cfpm !

marcus

[SteveSpencer]

If you are careful, it is possible to solder a small wire-wrap at the base of either 5v pin; use a small gauge enamel insulated copper wire normally used for magnet windings--works well.

I assume this is on the tall header, not the Pi, since the idea is that if a board dies, I can just swap it out, rather than have to do any soldering.

I build a speed controller for mine using ULN2803 (controls all three PIs) using pwm pin on each PI. (totally optional)

The fans I have are not all PWM controlled, but it's an interesting idea for the ones that are.

It is always better to pull the air into the case and blow it out the top.

Good to know. I have "modified" some cases to allow more air in through the bottom, and others have "LEGO" style acrylic base plates, with lots of holes.

Another alternative would be to use a small piece of tri-pad perforated board in combination with a through-header for better connection quality, as I don't have to worry about the wire coming loose from the header when I connect/disconnect it.

[MarkHaysHarris777]

I build a speed controller for mine using ULN2803 (controls all three PIs) using pwm pin on each PI. (totally optional)

The fans I have are not all PWM controlled, but it's an interesting idea for the ones that are.

All brushless 5v fans can be pwm controlled-- works very well. Use a frequency in the very low range of maybe 12-20 hz, and then keep the pulse width 'ON' at least 60% of the time (low) and 87-95% (high).

You will find that a pwm brushless 5v fan runs VERY quietly too. I have squirrel fans on my Zebra Cased PIs and without pwm they are very noisy after time (as dust forms on their fins). But, the pwm keeps the PI cool, and yet runs the fans at a low enough speed that they are whisper quiet.

marcus

[ntate6630]

Hi,

This is the fan configuration I use in one of my setups...

https://www.flickr.com/photos/nicktate/ ... ateposted/
https://www.flickr.com/photos/nicktate/ ... otostream/
https://www.flickr.com/photos/nicktate/ ... otostream/
https://www.flickr.com/photos/nicktate/ ... otostream/
https://www.flickr.com/photos/nicktate/ ... otostream/

I didn't use a 5 volt fan but a 12 volt one with a DC-DC convertor.
I bought the real time clock module form here...
https://www.abelectronics.co.uk/p/52/RTC-Pi-Plus

I modified the board to mount the fan.

This is the case I used...
http://www.modmypi.com/raspberry-pi/cas ... case-black

It works very well at keeping the Pi cool.

Regards
|Nick

[Koeshi]

Hi,

This is the fan configuration I use in one of my setups...

https://www.flickr.com/photos/nicktate/ ... ateposted/
https://www.flickr.com/photos/nicktate/ ... otostream/
https://www.flickr.com/photos/nicktate/ ... otostream/
https://www.flickr.com/photos/nicktate/ ... otostream/
https://www.flickr.com/photos/nicktate/ ... otostream/

I didn't use a 5 volt fan but a 12 volt one with a DC-DC convertor.
I bought the real time clock module form here...
https://www.abelectronics.co.uk/p/52/RTC-Pi-Plus

I modified the board to mount the fan.

This is the case I used...
http://www.modmypi.com/raspberry-pi/cas ... case-black

It works very well at keeping the Pi cool.

Regards
|Nick

VEry cool, loving the blue glow and that you have kept the GPIO pins exposed even with all that stacked on.