Looking to Add Cooling Fan Control to PiAware


I had my Pi located in the attic to keep it close to my rooftop antenna, but started receiving high temp warnings on my Stats page (ambient attic temps in Florida can be 140°F before adding computer processor heat). I am building a weather-tight enclosure to be located outdoors that will be painted white to reduce solar heat gain and will include cooling fans.

Since I now know that the Raspberry Pi has on-board temp sensors, can someone help me add code the PiAware that will control the fan based on processor temps? The fan will be powered by an external power supply, but I will need some sort of code to output and manipulate a PWM signal from the Pi to control the fan.

Any Pi experts out there?

http://www.pentairprotect.com/wcsstore/ExtendedSitesCatalogAssetStore/PentairDataLoad/EPSMedia/Hoffman/images/1DoorType12-13_os.gif http://images10.newegg.com/NeweggImage/ProductImageCompressAll300/A2V5_130325896195403815aDfENDD5P9.jpg


google found this piborg.org/chilledpi

Is it a metal box or plastic? - can you do something passive buy having an internal heatsink (to collect heat) connected to an external heatsink using heatpipes (copper bolts) through the case

someone has said, in Indonesia electronics boxes used for various things like this have sunshades - panels held an inch or two off the box, these heat up and the convect the heat away.


Temperature issues and methods of avoiding attic heat came up in this thread a few weeks ago: http://discussions.flightaware.com/ads-b-flight-tracking-f21/temperature-limitations-on-the-equipment-t26939.html

I’d recommend reading the entire thread. :wink:

Toward the bottom of the thread, I posted a pic of one of the setups I run and provided details of how I keep it cool. User ‘beckerm13’ also posted a pic of his setup, which has only the antenna in the heat and leaves the Pi and SDR dongle just on the other side of the ceiling in the air conditioning.

Unless you’re just hardcore about wanting to move it outside, I’d leave the antenna on the roof, install an inexpensive amp near the base of the antenna (just inside the attic if you don’t want to have to worry about waterproofing issues), and run as short of a piece of coax as you can get away with to the inside of a closet ceiling and mount the Pi there.

Even though this is a cool project, I think you’re going to go through more trouble and expense than it’s worth to install the Pi outdoors. If the length of the feed line from the rooftop antenna to the outside enclosure would end up being close to the same length of running the feed line down through the attic to the ceiling of a closet, it would be worthwhile to just do it that way to save the money on the enclosure setup and keep your Pi in the air conditioning. A couple of extra feet on the feed line from the antenna isn’t going to make a noticeable difference - and really won’t matter if you add an inexpensive amp.



It’s funny you brought this up - I just went through this last weekend. I initially had the Pi, amp, and antenna in the attic, but it was just too hot up there. I constructed a similar box that also includes a UPS, battery, cooling fan, and voltage converter.

The antenna (4-legged spider) and amp/filter are still in the attic, and I spliced into an unused RG-6 run to the office right below the antenna. The dongle is then hooked into the cable jack in that room. Works great!

The UPS module hooks up to AC power, the 12V battery, and to the USB converter. The USB fan has a USB passthrough, so it is plugged directly into the USB port of the converter, and the RPi is plugged into it. The fan just runs all the time, and it keeps the Pi about 10 degrees cooler than even when it was outside the box in the same room. The whole setup is actually very quiet.

I drilled some holes in each side of the box for airflow, plus 7/16" and 7/8" holes in the back for the power cable, ethernet, and RG-6.

Parts list in case anyone is interested
DC 12V-5V USB converter
USB cooling fan
12V UPS module
A UB1280 battery (12V 8ah)
Cable glands like these in whatever size you need


Nice job. It appears that you’ve covered all of the bases and put a lot of thought in to this.

On that note, I do have one question:

You did all of this…and this setup still sits on the floor inside the house in the air conditioning? :slight_smile:



Yeah, the original plan was to put it all in the attic, but I decided that was not doable due to the climate up there, so this was an audible. The reason for the box is that there are semi-exposed electrical components, so I didn’t want it just laying around in the open. I’m actually happier with this setup, since it’s a lot easier to get to the parts that are likely to need servicing. I can’t say I really enjoyed my time in the attic. :slight_smile:



I get your point, I guess my PI doesn’t suffer that much but I do have a fan that attaches to the PI’s pins and runs constantly. (I couldn’t measure the speed but it runs on maximum RPM).

Like above you’ve got it well thought out however I wouldn’t really see the need of an alternating speed as I guess the cooler - the better.

Nice UPS above - was planning on doing something like this :slight_smile: Just given me an idea what’s achievable though.


Fans never hurt…unless they’re using hot air to ‘cool’ hot metal in an attic or sealed enclosure - and then they’re basically useless. :slight_smile:



AndyHill74 - I finally finished my enclosure. The power supply is a bit overkill, but work had a bunch of retired Dells in the e-waste bin. Without a PWM signal, the 12v fan runs wide open and sounds like a jet. I’ll try one of the 5v taps and if that’s too slow, I’ll go back to the 12v and drop in a diode or two.

The enclosure will be mounted about 20 feet up on a used Rohn 25G tower I just picked up, just below the eave of the house. Because it was cheaper than coax, the SDR dongle will be up with the antenna on top with a 33’ active repeater USB extension cable down to the enclosure. GFCI power and the cat 5 are run from the attic, out the eave, down to a drip loop and up into the closure.

I’ll be working on the tower next. I’ll post more when that’s done.



i just zip tied the pi case to a laptop cooling fan (was free after rebate at frys), better than nothin =p