Raspberry Pi Bay - 4 slots

Good morning, folks!

UPDATE 18/09/2021: I added the .step file for those who would like to modify the design.

UPDATE 30/01/2021: Added, as requested in comments, 3 adapters for 40mm fans. I used a Noctua NF-A4x10 for the design.
Fan_Holder_40mm_Close: Only one vent for the fan.
Fan_Holder_40mm_Open: Opened chassis to benefit from the airflow produced by the fan all around it. Might be quieter the the close version, and airflow might be more homogeneous into space.
Fan_Holder_40mm_x4: Adapter to use 4 fans of 40mm. I am not sure if this is really better than a 90mm fan in term of noise and even flow, but just in cas ^^

I'm super happy to present you my latest design. I took advantage of this quarantine period to learn a bit more about programming, and I set up several Raspberry Pi (RPi) as small home servers for several applications (chat, home cloud, VPN, etc.). However, after a while, I ended up having several raspberry pi hanging around my router. With the heat we've had recently, the Pi's were reaching over 55°C. Even though it's not a real problem, I thought that having a system to store them together and keep them cool would be a good thing for the upcoming summer. I have a hard drive bay attached to my NAS, and I though that such system would be inspiring and that is why I come with a raspberry pi bay where we can easily and quickly swap pi drives for different applications and tests.

This bay is composed of several interchangeable parts. Most of them are easily customizable to fit other needs/designs.

Here, the supplied set is made for a 92mm fan. I wanted to have the quietest solution, so I opted for a BeQuiet! 92mm PureWings 2. I quickly soldered two dupont male connectors to a micro-usb cable in order to be able to connect the fan to a usb port. Of course, it's easy to rework the fan adapter a bit to fit smaller fans. I'll put some other versions online when I have some free time.

Also, I've added several types of covers that offer different ventilation options. The one I printed is a dual system. The top vent can be opened or closed as needed. Select the grid version if you need more airflow, and the plain version if you need less. In all cases, the top cover also includes a grid to ensure that air can escape.

The same modularity is available for the back plates. At the moment, two versions are available: a simple version if you don't have a Pi in this housing or if you don't need to connect a cable to it, and a version with a hole for the internet cable to connect it to an RPi 2 or 3. I will soon provide other versions with holes for the USB and ethernet ports of the RPi 4.

Finally, for the dust filters, my printed version uses a honeycomb filter with a 10 to 20% infill depending on the filter. But don't hesitate to choose the one you prefer.

The Raspberry Pi racks I designed are compatible with the Raspberry Pi 2B, 3B and 3B+ models. They should also be compatible with the 4B versions of Raspberry Pi, but I haven't been able to test them yet. Also, the RPi 4B has a inverted layout compared to the previous version regarding the position of the ethernet port, so it won't work with the RPi3 back plate.
I also added a rack version that doesn't use the snap&lock system ("Rack_RPi3_S"), but that gives you the possibility to screw the RPi onto it. For this you need 2.5 or 3mm diameter screws. Still, I advice to use the snap&lock version ("Rack_RPi3_*N*S") as it works great an it's much simpler.

Furthermore, according to this benchmark, the RPi 3B is much more energy efficient than the RPi 3B+ and RPi 4B. Therefore, if you want to save energy for economic or environmental reasons, I strongly advise you to opt for the 3B version. It is quite capable of running light applications (such as chat servers (Rocket.Chat, mumble, etc.), VPN, etc.).

List of material used (except 3D printed parts):
1 Raspberry Pi 3B
1 Raspberry Pi 3B+
1 BeQuiet! 92mm PureWings 2 fan
2 micro-usb cables
1 USB cable + 2 male dupont cables (soldered, for fan USB power)

Additional info:

In my case I added some furniture pads in the bottom part where the fan adapter is in contact with the piece, to reduce vibration and noise. For this you need to use the "Case_Bot_Pads" version of the part, with 15x4mm round or square pads. Otherwise, you just need to print the "Case_Bot_NoPads" version of the part.

For more info about the printing parameters I used, please have a look at the dedicated section bellow.

An assembly video is available here: https://www.youtube.com/watch?v=gMeAFoPIWX0

After testing, my Raspberry Pi are now around 47°C (against 55°C previously), with a room ambiant temperature of 27°C and 2 RPi loaded. So I can consider this bay as successfully working.