Active Cooling Enclosure for Raspberry Pi Zero 2

         I developed this case because I have a Raspberry Pi Zero 2 connected to an adapter for Raspberry Pi Zero with Ethernet (PoE / Ethernet / USB HUB Hat), which I use to run Pi-hole. However, its temperature was always too high, reaching around 60°C. I couldn't find any case with active cooling that would fit this setup, so I decided to design and adapt one myself.

         After installing this cooling system, I was able to reduce the temperature to around 38°C without the filter and 41°C with the filter, significantly improving thermal performance.

         Since I had all the necessary components at home, I figured it was worth the effort. However, this might not be the most cost-effective option if you need to buy everything from scratch.

List of Materials Used:

1. 3D-printed parts
2. a piece of nylon stocking (used as a fan filter)
3. 3D printing adhesive (use your preferred glue)
4. square nuts for M3 screws, approximately 2mm thick (various thicknesses exist, but I used 2mm)
5. two M3x30 screws
6. fan – Noctua NF-A4x10 5V
7. noise reducer – since I connected the fan directly to a 5V USB port, I used an old USB cable and added a Noctua NA-RC10 noise reducer that I had lying around
8. adapter for Raspberry Pi Zero with Ethernet (PoE / Ethernet / USB HUB Hat)
9. Raspberry Pi Zero 2

This is the adapter that I use: 

(https://www.aliexpress.com/item/1005003434975004.html?spm=a2g0o.order_list.order_list_main.40.45ff1802jZ4Inv)

1. Installing the Adapter

         The first step is simple: attach the adapter to the Raspberry Pi Zero 2 following the manufacturer's instructions. The adapter already comes with the necessary screws, which I used to secure it inside the case.

         At this point, you can also insert the M3 square nuts into their respective slots, as they will be used to mount the cooler. During my tests, without the filter, the temperature stabilized at 38°C. With the filter installed, it remained at 41°C.

2. Preparing the Power Cable

          To power the fan, I first disassembled a USB cable, keeping only the positive and negative wires. Then, I also disassembled a Noctua noise reducer (Noctua NA-RC10) and adapted it into the positive wire of the USB cable.

⚠ Remember to connect the noise reducer (or diode) with the correct polarity! If reversed, the fan will not turn on. See below for detailed instructions.

          Next, I took the Noctua NF-A4x10 5V fan, cut its cables, stripped the positive and negative wires, and removed the yellow wire, which is not needed in this setup.

          I then connected the USB cable, Noctua fan, and noise reducer, ensuring a solid connection.

3. Printing and Assembling the Filter

         For the filter, I printed both the male and female parts, placed a piece of nylon stocking between them, applied glue, and closed the filter.

         A key tip is to stretch the nylon as much as possible before securing it. If it's too loose, the filter can block airflow. This method is widely documented among PC builders as an effective dust filter solution.

4. Final Assembly

         Now, all that’s left is to align the filter and fan and secure them in place using screws. The case is designed for four M3x30 screws, but I found that two screws were more than enough to hold everything securely.

         After assembling everything, simply plug the fan into a USB port, and your Raspberry Pi Zero 2 is ready to use with improved cooling!

         Optional with a decoratvie cover.

Optional 2 – Decorative logo for MMU printers.
I included a Pi-hole logo (3mf file) that you can print and stick on the case.

Enjoy!

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                                        💡 About Noise Adapters

         When connecting a Noctua 40x10mm 5V fan directly to a USB power source, it runs at maximum speed (5000 RPM), which can be quite noisy. To reduce the noise, I tested Noctua Noise Adapters because I had them available. However, if you’re considering buying a solution, using diodes might be a more cost-effective alternative.

                                          Noctua Noise Adapters Tested

         Since I had multiple Noctua Noise Adapters available, I tested them to see which would effectively reduce noise while keeping the fan operational. Here are the results:

• NA-RC7 → Very good – almost the same as RC10.
• NA-RC10 → Excellent – the best balance of noise reduction and fan performance.
• NA-RC6, NA-RC12, and NA-RC11 → Did not work effectively with the 5V fan.

         If you already have Noctua Noise Adapters, using the NA-RC10 is a great solution. However, if you are looking to buy something specifically for this purpose, a diode-based solution might be a better choice.

                                      Alternative: Using Diodes to Reduce Voltage

         If you don’t have a Noctua Noise Adapter and want a more controlled voltage reduction, you can use diodes in series on the red (+5V) USB wire. Each diode drops the voltage by approximately 0.7V, allowing for different speed adjustments.

My the goal is to reach around 3V. 

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           ⚠ Important Notice: Correct Polarity & Alternative Power Options

         When using Noctua Noise Adapters or diodes to reduce fan noise, the correct polarity is essential.

✅ Noctua Noise Adapters (if used as-is) have the correct wiring and can be plugged directly between the power source and the fan.
❌ If you cut the Noise Adapter and expose the diode, you must connect it with the correct polarity.

✅ Diode Wiring:

• Anode (unmarked side) → Connects to 5V power source.
• Cathode (striped side) → Connects to fan's power wire.

🔴 If the diode is reversed, the fan will NOT turn on. Always check the orientation before installation.

                                   Alternative: Use the Raspberry Pi GPIO 3.3V Pin

If you are using a model with accessible GPIO pins, you can connect the Noctua 40x10mm 5V fan directly to the 3.3V pin instead of 5V.

💡 Advantages of using the 3.3V pin:
✔ No need for diodes or Noise Adapters.
✔ The fan runs at a lower speed, reducing noise naturally.

         If you're using a Raspberry Pi Zero, check if the GPIO header is installed. If available, you can use the 3.3V pin for a quieter fan setup without additional modifications. 🚀

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Additional Note: Second Test with Noctua NF-A4x20 5V

For another project, I used a Noctua NF-A4x20 5V fan, as shown in the image. I tested multiple Noctua Noise Adapters, but this time, I did not have an NA-RC10 available. Instead, I tested:

• NA-RC6, NA-RC7, and NA-RC11 → All worked well.
• I ended up using NA-RC6, as it produced the least noticeable noise while maintaining similar performance to the others.

🔹 Again, I used this Noctua fan simply because I had it available. I did not purchase anything specifically for this setup.

⚠ However, this setup was not as effective in controlling temperatures compared to the first one, for some reason.