New product: Raspberry Pi 4 Case Fan

Today we’re launching a stocking-filler product to help you squeeze more performance out of your Raspberry Pi 4. The $5 Raspberry Pi 4 Case Fan clips inside the lid of the Official Case, and keeps your Raspberry Pi 4 cool even when running the heaviest workloads, at the most aggressive overclocks.

Raspberry Pi 4 power optimisation

Like all electronic products, Raspberry Pi generates waste heat as it works. Along with most fanless products – like most mobile phones – Raspberry Pi 4 was originally designed to operate in a “sprint-and-recover” mode: if run at maximum performance for an extended period it would heat up, and eventually throttle back to limit its temperature.

What’s in the box?

In practice, the power optimisation work that we’ve done over the last eighteen months has largely eliminated throttling for an uncased board, operating at the stock clock frequency of 1.5GHz, and in a typical ambient temperature.

Here’s a graph of temperature during a quad-core compile of the Linux kernel: you can see the temperature barely exceeds 70C.

Quad-core kernel compile without case

Turning your Raspberry Pi “up to eleven”

But maybe you want to put your Raspberry Pi in a case; or you’ve noticed that your Raspberry Pi will overclock to 1.8GHz or more; or you want to use it in a higher ambient temperature. All of these things can put us back in sprint-and-recover mode.

Here’s the same workload running on a board in a Raspberry Pi official case: now we hit the 80C throttle point and slow down, and the compile job takes (slightly) longer to complete.

Quad-core kernel compile in Raspberry Pi 4 Official Case

To run indefinitely at full speed under these conditions you’ll need either a passive cooling solution (like the excellent Flirc case), or an active one like the Raspberry Pi 4 Case Fan. It draws air in over the USB and Ethernet connectors, passes it over a small finned heatsink attached to the processor, and exhausts it through the SD card slot. Here’s our workload running with the case fan: now the board remains well below 70C, and as expected the compile job takes the same amount of time as on the uncased board.

Gordon Hollingworth will be here on Wednesday to talk about how he designed the Raspberry Pi 4 Case Fan ducting with the aid of a stack of Chinese takeout boxes and a glue gun. 

Get your Raspberry Pi 4 Case Fan today

As with all our products, the Raspberry Pi Case Fan is available from our Raspberry Pi Approved Resellers. Simply head over to the Case Fan page and select your country from the drop-down menu.

If your country isn’t on the list yet, don’t worry, we’re constantly working to add further countries and resellers to the list. Until then, check out some of our Approved Resellers that offer international shipping.

79 comments
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What’s its MTBF or MTTF figure? And noise? Can it be turned off via GPIO?
Regarding overclocking, I’ve overclocked RPI4 model B 8GB up to 2350MHz with over_voltage=10, seems to be stable with PTS. One question: how to overclock it even higher? I aim at 3GHz with liquid Nitrogen cooling. What is the highest frequency that the firmware (presumably experimental) allows? Can we have “Overclockers version” of firmware?
Thanks for anybody’s answer. I’d like to make another LN2 session before Santan comes without resorting to exotic methods like using external reference clock.

Reply to CooliPi

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1) The fan’s specified lifetime is around 30,000 hours
2) It’s a relatively low noise fan (in comparison to the first one I tried!)
3) Yes the blue wire is a PWM input, which you can wire to a GPIO to control it. We have added an option to raspi-config to enable the fan on GPIO14.

Reply to Gordon Hollingworth

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isn’t GPIO14 the default value only? User can assign a GPIO and adjust the temp level when the fan kicks in.

Reply to aBUGSworstnightmare

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Yes, that’s correct, you can use any GPIO pin you feel like (and even a PWM output if you really want to do that, but you’d have to configure that yourself)

Reply to Gordon Hollingworth

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Gordon, nice product! I have a suggestion for the next version (4B+? 5?) that I detailed on Reddit https://www.reddit.com/r/RaspberryPi4/comments/k39zkk/raspi_5_needs_an_official_fan_option/ . Feel free to delete this when you’ve seen it.

Reply to A. Peter Allan

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That fan you propose in your design is £8 in quantity. Way too expensive. And you have assumed that any Pi5 would need active cooling which may not be the case.

Reply to James Hughes

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It might not be a case fan ;-)

Sorry

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Out of curiosity, why did you settle on GPIO 14 rather than GPIO12, which has a hardware PWM capability? GPIO14 is also the TXD pin for the serial console, which would prevent you from using both the fan and a serial console.

Reply to Geoff

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Just for simplicity of connecting and documenting…

There isn’t really any point of using PWM here, I tried and there was no advantage, you just end up with the fan continuously whining. I think it’s better to just turn on when you hit 80 degrees and turn it off when it goes below the hysteresis threshold.

Reply to Gordon Hollingworth

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Am I misinterpreting the graphs, or there is no change in compile time, just running 5°C cooler?

Reply to Michal Smrž

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Without a case at all, it won’t throttle building the Linux kernel (that’s the first graph), with the case it’ll throttle (that’s the second graph). With the Raspberry Pi Case Fan it won’t throttle again and therefore returns to the same performance as the first graph.

Reply to Gordon Hollingworth

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So main problem is bad case design and cooler is not solution but workaround?

Reply to Michal Smrž

Eben Upton

No, main problem is “physics”, and cooler is “engineering”.

Reply to Eben Upton

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Every single case will cause a rise on the temperature.
The, the engineering comes to design a passive (heatsink) and active (fan) system to dissipate (In a certain degree) the heat generated by the board.

It’s not magic.

Reply to Jorge

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Every single case apart from those designed specifically for cooling, like the FLIRC for example.

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I guess the local minimum around 3000s is the pause between compiler and linker. Without cooling it seems to be around 3200s

Reply to crumble

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I have a fan case, but I didn’t bother to install the heatsink. It works fine because it’s an open sided case. I wonder if the heatsink is necessary here, or if I can just drill ventilation holes on top of the case.
Also, it has 3 wires? My fan only has two, and well, it is constant on. I wonder if I can simply use two. Can I install just the fan program without updating the whole OS?
At worst, I should be able to write my own program for it. I know there exist commands to get temperature from cli, as well as turning gpio on or off. I just don’t know what.
Regardless, I think it is a good product to have. I certainly will be looking to pick one up if my current fan somehow stops functioning.
Thank you for producing it.

Reply to Harry Hardjono

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To enable the fan without updating you can just add the following line to your config.txt file:

dtoverlay=gpio-fan,gpiopin=14,temp=80000

Adjust gpiopin and temp as necessary…

Reply to Gordon Hollingworth

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I got some and they’re OK. They have a whiny noise that would be annoying in an office, even when snapped closed in the case. Maybe PWM would help with that. I used the firmware setting “dtoverlay=gpio-fan,gpiopin=14,temp=75000” in /boot/firmware/usercfg.txt on Ubuntu. It looks like there is 10 degrees of hysteresis below the 75C limit. Under heavy load it cycles between 65C and 75C a few times then builds up heat in the case and stays on around 67C. If I split the case open a little to circulate air, it goes back to cycling. On another Pi4 I have a smaller fan (20x20x5) zip-tied to a case lid with a hole, and exit holes drilled along the GPIO pin region. It works much better with CPU about 43C under full load, but it’s always on and it’s similarly noisy.
I’m using it to replicate ZFS from a NAS to an external HDD. When the tasks run and there’s new data it loads 100%, but most of the time it’s idle, so the off state will greatly extend life and reliability. Maybe your fan with a drilled case would be acceptable. I have a FLIRC case ordered too, so that might be good enough with no moving parts.

Reply to A. Peter Allan

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Where the exhaust ? The fan brings in cold air, where the warm air gets out from ?

Reply to Timg

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its in the text:
” It draws air in over the USB and Ethernet connectors, passes it over a small finned heatsink attached to the processor, and exhausts it through the SD card slot.”

As was already known, there is only a minimal amount of airflow needed to substantially cool the sOC, below the temperature where throttling is necessary.

Reply to mahjongg

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Watched the video now. Additional question, no input for cold air to get in. I think this design could be better with cold air input and hot air exhaust

Reply to Timg

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It looks like it relies on the small gaps around the I/O ports for intake and exhaust airflow. Intake is at the Ethernet/USB end, exhaust mainly through the MicroSD slot. It doesn’t need to move a lot of air, just enough to simulate free-air convective flow that occurs without the case.

Reply to Chromatix

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That’s correct, what you really want is a blog all about how I designed the case and the process I went through to get to the design we have? Better wait for Wednesday’s post then!

Reply to Gordon Hollingworth

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can I use gpio-fan pwm output to directly control 5V pc fan such as https://noctua.at/en/products/fan/nf-a4x10-5v-pwm ?

Reply to Ľubor Slušný

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gpio-fan isn’t a PWM output, it’s is an on-off bang-bang controller. But yes it’d work with that fan.

Reply to Gordon Hollingworth

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Hi,
I’ve had that fan for a while now. I’ve tried using the new software support for fans to control it, but I haven’t been successful. How should I wire the fan (do I use the 3 to 2 pin adapter) and set up the software so that it will be controlled for temperature?

Thanks!

Reply to Joe

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Hi Gordon, in response to James you mentioned that the RPi5 might not need active cooling, can you explain how the RPi5 cooling works ;-) Great to see the Foundation get behind an official fan, any chance of a case lid with holes in the raspberry?

Reply to John

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There is no Pi5 yet. So who knows whether it needs cooling or not….

Reply to James Hughes

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I’m just guessing, but it’s possible that a new case design will be involved, one with aluminum casing, attached directly onto the CPU to act like a gigantic heatsink. Less likely, that it will be shaped like a coffee mug warmer so you can sip and dip while doing coding. Just saying. ;)

Reply to Harry Hardjono

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Now we know what the fan control settings was for under the performance TAB, nice :)

Reply to Ray Allen

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This is very nice for people with moderate use of a Pi4. For the people that are pushing the limits there are options such as the Ice Cooler. For $5 though, this is a great solution for most people.

Reply to James Carroll

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I think the graphs make an important point: in most non-overclocking, real-life situations even with all four cores working continually and the board inside a case, the performance gain with added cooling looks pretty small (2/30 or about 7%). There’s some fun to optimizing, but for typical situations it sure looks like it really doesn’t matter much. Though you have a really hot ambient, it would matter more.

Reply to jbeale

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It’s not just about that only hard-core user need am active cooling system.

Every CPU, CI or any other electronic component is affected by its temperature, so, if you want to use your Raspberry for a long time, you must to install/use a cooling system.

Reply to Jorge

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So, yes electronics are affected in the long term by its running temperature, but we begin throttling the temperature at 80 degrees, rather than the rated temperature of 125 degrees. So you can expect no lifetime issues with any Raspberry Pi even if it is run at 80 degrees for its lifetime.

Reply to Gordon Hollingworth

Eben Upton

As Gordon says, 80C is quite cool from the perspective of electronics. If we didn’t care so much about your fingers we could let it run out to >100C, with some modest derating for SDRAM refresh and timing parameters.

Reply to Eben Upton

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Regarding derating, keep in mind that microSD card is affected too – and running it at 80˚C plus its own temperature rise makes frying it way more likely. It heats up mainly upon writes. In electronics, for roughly every 10˚C of increase in temperature, the lifetime/MTBF halves (see Arrhenius equation). In practice, it’s not that bad, I suspect that mainly some devices with fluid electrolyte (like exploding capacitors) are affected widely.
What needs derating is certainly inductors around the PMIC, because they loose their ability to hold energy with increased temperature. A prime example in Raspberry Pi ecosystem is a comparison between RPI4 1/2/4GB vs. 8GB model (the latter has increased frequency of its PMIC and a different inductor at least on the 1V rail. If you overclock 1/2/4GB models and load all the cores to the max, it stresses its PMIC so hard that it starts to show signs of dependency on temperature – if you increase temperature, it reboots because it can’t supply enough power on that 1V rail. Raspberry Pi 4 8GB is way more relaxed thanks to a different inductor running at 50% higher frequency, effectively pumping in 50% more power (voltages are the same).
So, if you want to overclock it in an official case, make sure you cool it somehow. If you go above 2GHz, I’d recommend 8GB model just because of this. But I dunno whether would power users go with an official case…
A few links at the end – derating graphs for power inductors:
https://passive-components.eu/power-inductors-2-cont/
You can see that it gradually loses its ability to hold energy with increased temperature.
Last but not least, it shouldn’t burn fingers as per BS EN 13202:2000 or UL 60950-1. Highest temperature of a bare metal is at 70˚C (1 second contact) and derates to about 44˚C (infinite or hours long contact).
So, saying that it could run at high temperatures is not exactly accurate. It could, but the price for it lies in overrated components to handle the current.

Reply to CooliPi

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This is like one of those infamous twitter thread where someone steps in to explain a book to its writer, or a film to its director.

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Would be cool to allow that for people who know to keep their fingers off a hot Pi :-)

Reply to Max

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Hey is this fan just like the one of the official Raspberry Pi PoE HAT? Or is it better? Or does my question not make any sense?

Reply to td540

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Yes it contains a fan, but the fan is not as strong as the PoE HAT fan, which makes it much quieter.

Reply to Gordon Hollingworth

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This fan should have existed earlier! The heat development from the Pi4 is known. In short, better later than not at all ;)

Reply to Martin

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Out of interest, why is the Linux Kernel compilation not any faster when OCd with the Fan?
Surely it should make some performance increase OCing the 4 cores by 0.3Ghz?

Reply to Gregory Wilson

Eben Upton

Ah very simple – it’s not overclocked. Still at 1.5GHz.

Reply to Eben Upton

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I noticed the heatsink positioning, with the fins perpendicular to the airflow… is this noticeably beter than placing it with the fins parallel to the airflow, not much difference or actually not done optimally in the video? If it is better, will the reasons be mentioned in wednesday video?

Reply to Paulo

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Hey Paulo,
You noticed the one thing that I also saw! Yeah, I think for best performance it makes sense that the heatsink is mounted with the fins in line with the air flow. Although I haven’t actually tested the difference (it’s probably a very minor difference)

Reply to Gordon Hollingworth

Eben Upton

In my experience it’s not particularly significant. I tend to align it at 90 degrees to the way shown in the video, but this is just out of a vague superstitious belief that I’ll get smoother airflow and better heat transfer.

Reply to Eben Upton

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Aligning heat sink fins with flow direction is the way to go. You want as much air flow as possible to dissipate heat and with a given fan the way to do this is to minimize pressure drop while maximizing air speed along the surfaces to be cooled. Mounting the heat sink with fins perpendicular to airflow decreased cooling performance. On a side note: a large diameter fan that rotates slowly is more efficient (and quiet) than a small diameter fan that rotates quickly (when both provide the same amount of airflow [m3/s]).

Reply to Martin

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Surely turbulent flow over the heat sink would provide better heat transfer than smooth flow.
I don’t see any noise/ sound specification for the fan, is that intentional ?

Reply to Paul Salmon

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I realize this particular product is only for the Pi 4 and official case, but would something like this be necessary for the Pi 400 to do similar workloads?

Reply to Mark Gardner

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The PI 400 has a large heatsink, making the need for active cooling less important.

Reply to Michael Eric Menk

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What size is this fan? I’m considering it for my Dreamcast and wondering if it would fit.

Reply to Arthur

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Cool! I love it

Reply to Fran

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It is safe to connect a fan directly in the gpio pins ?

Reply to yan

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I want to praise the excellent work with the new case fan and take the opportunity to ask why the standard Raspberry case was not changed by placing air inlet and outlet openings on the top and bottom of the case, this would not help in reducing the processor temperature Raspberry pi4?

Reply to Renato Vander

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Why should I choose this product over a set of heatsinks for $2 USD? Will the case fan add much more than the heatsinks would? Should I wait and just get this? Should I get both?

Reply to Colin Andrews

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Colin, heatsinks in a case will do less for you than this active cooler. If you’re running your Pi without case, or a very open case design, than heatsinks should work OK. Also consider getting a FLIRC case, if you’re interested in having an absolutely quiet Pi.
TL;DR: The fan is better if used with the official case than heatsinks

Reply to Max

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I have a few tiny USB3 sticks I runs OS’s on, they can get quite warm/hot. This should pull heat out of the USB3 connectors. Worth a try, getting a bit warm here in Oz.

Reply to Gavin McIntosh

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I have the Canakit heat sinks on my Raspberry Pi. Would I have to take it off and use the one that is included with the fan to get the performance?

Reply to Braden Gibbons

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While this seems to very adequately address the over heating issues with the pi4 case it’s still impossible to access the GPIOs without removing the lid. But then the fan can’t be used (though that’s less important with the lid off and the fan power connections would need to be altered anyway).

Reply to Paul Milton

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Which type of thermal grease you’ll recommend with this one, can I use the same one which I use in my desktop.

Reply to Atul Host

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The heat sink comes with a pre-applied thermal adhesive pad. You peel off the protective cover, then stick the thing onto the SoC.

If you really wanted to, you could scrape off the adhesive and put on your own paste, but it’s a bit of a diminishing return—technically even without the extra heat spreader, the fan alone will continue to do its work preventing throttling just fine.

Reply to Jeff Geerling

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Mine has the most annoying high pitched squeal,

Reply to Paul Salmon

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I bought one today, installed it, turned it on and I smelled some smoke :( . I misconnected the wires to pins 2,4,6 instead of pins 4,6,8 thereby I fried the fan controller IC. You should warn the buyers of this and ask them to make sure the pins are connected right, before connecting the Pi to the power supply. I learned it the hard way.

Reply to Molnár Máté

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Hi Molnár. We’re sorry to hear that – connecting the wrong thing to a power pin will do this, but we’re updating the product page and product brief to emphasise that great care is necessary in making these connections in order to avoid damaging the fan. I’ve sent you an email to see if we can help make sure you end up with a non-fried and working fan.

Reply to Helen Lynn

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I just received my Case Fan today, and wanted to compare it to my little drilled-out hole in the top of the case along with a 5v Pi Fan I use when I put a Pi in the official case.

It does have a bit of an annoying higher-pitched buzz to it (almost like the sound you get with interference on an unbalanced audio system if you turn headphones waaaay up), but the fact it turns on only at 80°C (or a temp of your choosing) for a short bit makes that less of an issue.

It’s a nice little piece of hardware for $5, I just hope the next official Pi case (maybe for a future Pi 5?) might have better thermal management built-in (even if it requires an active fan… but hopefully not!).

Reply to Jeff Geerling

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I suggest a filter for the fan to collect dust in the next iteration. My SFF PC needs dust removal every few months to keep it running quietly, and my Pi 3 and Pi 4 with fans also need regular cleaning. My Pis have external fans so this is easy to do, the PC and this fan are internal so need stripping down to check and clean. A decent filter makes this much easier.

Reply to David Morton

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Hi there. Great product!
Being a opensouce fan I am wondering is it possible to bring some privacy options to raspberry pi with (e.g. kill switches for wifi, bluetooth, gps, mic, webcam ports etc.) via gpio or something else?
Thanks,

Reply to privacy is a human right

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At:https://www.raspberrypi.org/products/raspberry-pi-4-case-fan/?resellerType=home
You say 18mm × 18mm × 10mm heatsink but the fan in the video is much shorter than 10mm! Please confirm the height, we need to fit an RTC in with it at the same time a 6mm heatsink allows this.

Reply to Chris Evans

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Doh! I meant Of course “but the HEATSINK in the video…”

Reply to Chris Evans

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Just got this and installed it. No matter what temperature I set the fan to come on in settings, it just stays at the default 80 degrees. Any ideas?

Reply to Mark

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You really should’ve put reverse polarity protection on the circuit. It’s easy to accidentally wire it up in reverse and it fries the controller in seconds. I learned it the hard way…

Reply to Matthew

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Hi there!
I have a 2 PIN fan, which now operates 24/7. Its connected to PIN 2 and PIN 4. How can i make it work with this new fan control feature?

Reply to Andrew

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You can’t. Fan control only works with three wire fans.

Reply to Chris Evans

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Hello,
I inadvertently exchanged the red and black cable.
Then I saw my mistake and laid the cables correctly.
But now the fan does not work.
Could it be burned from wrong connecting?

Reply to Antonio

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I would like one of these for my Raspberry Pi 3B with official case. Is there one available or would this one work? I work it hard and it gets pretty hot! I like the official case and would like to keep using it.

Reply to Thomas

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My Raspberry Pi4 kit came with an OKDO standard case.
Will the fan fit this case as well?
And if not is a version for OKDO is planned?

Reply to Momo

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I’m afraid this will only fit the official Raspberry Pi case.

Reply to James Adams

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What’s the exact model/brand of the heat sink? I’d like to buy one without a fan.

Reply to Johan Tibell

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