Raspberry Pi 4 40mm Fan Exposed GPIO Case

thingiverse

Remixed from CubicMilliliter's design here: https://www.thingiverse.com/thing:4757917 It had everything I needed: Raspberry Pi 4, exposed GPIO, case fan and lightweight. Except, I wanted it to have just one 40mm fan. CubicMilliliter's original description below: ======== This is a press-fit Raspberry Pi 4 dual-40mm-externally-installed-fan case, which also exposes the GPIO pins. This design attempts to combine various elements from other Thingiverse contributions, which I could not find an existing all-in-one design for, like: The overall excellent case design by John_Sinclair: https://www.thingiverse.com/thing:3723481 Designs that expost the GPIO pins: https://www.thingiverse.com/thing:3810243 https://www.thingiverse.com/thing:4111015 https://www.thingiverse.com/thing:4611202 Designs that allow for dual fans: https://www.thingiverse.com/thing:4020155 (30mm fans) https://www.thingiverse.com/thing:4611202 (40mm internal fans) The design by Spyross (https://www.thingiverse.com/thing:4611202) got the closest to what I was looking for, but the combination of the internal mounting for the fans (which I had already learned from the one-fan case by John_Sinclair [https://www.thingiverse.com/thing:3723481] that internal mounting is a tight fit and difficult for me to work with), and the fact that I wanted to use full 4-pin PWM/RPM fans, meant that external mounting of the fans would be better for my use case. The case is press-fit, and should comfortably stay together if not explicitly attempting to separate the parts again, but will yield without much difficulty if actually attempting to pull the case apart again. The design by John_Sinclair (https://www.thingiverse.com/thing:3723481) is a much stronger press-fit than this if that is desired. There is plenty of space within the case, and in general this design overall less compact than other designs. This is a plus for me, but you may wish to check out other designs if maximizing compactness is a priority. The USB/Ethernet port "separators" are internally reinforced (see pictures) to prevent them from snapping off when pressing the case together or repeatedly separating the components. M2.5 bolts/nuts [https://smile.amazon.com/gp/product/B08NCCZYX2] can be used to secure the Pi 4 to the bottom case component if desired, though the Pi 4 happily stays put without within the case, without securing hardware, due to the internal separating wall exposing the GPIO pins once the case is assembled. This case fits 40mm fans, such as [https://noctua.at/en/nf-a4x10-5v-pwm]. Note that this brand of 5V fans in particular in my personal, non-guaranteed research and experience (please do your own independent research before connecting anything to the pins of your Pi 4), seem to be safe to power with the 3.3V line on the Pi 4, which even at "full speed" is inaudibly silent and in my home is able to cool the Pi 4 to below 30C. Connecting to 5V is of course also an option, but is audible unless the PWM line is used to lower the speed of the fan. The fan is virtually silent at half-speed, and silent below half-speed, when controlled by PWM at 5V input power. Note that this brand of 5V PWM-controlled fans in particular in my personal, non-guaranteed research and experience (please do your own independent research before connecting anything to the pins of your Pi), seem to be safe to control the PWM input directly through a Pi GPIO pin. Note that my understanding is that it is not safe to connect the fan RPM output directly to a GPIO pin on the Pi 4. Intervening circuitry (possibly, but maybe not, just a small resistor) is necessary to make this connection safe. One possibly-useful source for additional research on the topic of connecting the PWM input and RPM output of your fans to your Pi 4 is https://blog.driftking.tw/en/2019/11/Using-Raspberry-Pi-to-Control-a-PWM-Fan-and-Monitor-its-Speed/ . Personally, I have had the most success writing a fan controller for my Pi 4 using the unofficial Python wrapper for the WiringPi library (https://github.com/WiringPi/WiringPi-Python and http://wiringpi.com/). The picture which shows one fan spinning and one fan idle is a result of logic in my own fan controller script which does exactly that when the CPU temperature is low enough. Do not contact the author of WiringPi about any issues encountered while using the unofficial Python wrapper. Also included is a sample "fan cover" design which can be optionally mounted on the top of a fan that is pointed to blow inward into the case. I tend to choose to orient fans to blow inward onto the Pi 4 as this appears to provide consistently better cooling than an "exhaust" orientation.