DIY Air Filter with Xiaomi Filter and PWM Fan

This is a DIY air filter based on a round Xiaomi replacement filter and a 12V PC fan with dual bearings and particularly high static pressure. The fan is controlled via an inexpensive PWM controller, so volume and airflow are adjustable. A 6×3 mm gasket ensures the tightest possible connection between the fan housing and the filter. All parts are easy to print and can be assembled. The feet can also be mounted with M4×10mm screws, but gluing is also an option.
I run the fan at about 30% and get good results with very low noise.

Fan Recommendations

Any 14cm fan with a thickness under 30mm should fit. However, I recommend the linked model: ARCTIC P14 Pro PST CO. This offers high airflow and high pressure. Also, dual bearings for a very long lifespan:
Airflow: 110 cfm | 186 m³/h
Pressure: 5.2 mmH₂O
 

Approximate Component List

• Phone Charger
• Xiaomi round air filter: https://www.amazon.de/dp/B0DQQZ2FWN?ref=ppx_yo2ov_dt_b_fed_asin_title
• 12V blower fan with dual bearings - ARCTIC P14 Pro PST CO: https://www.amazon.de/dp/B0DPX4TWW7?ref=ppx_yo2ov_dt_b_fed_asin_title&th=1
• Option 1 - PWM fan controller (Type 3): https://de.aliexpress.com/item/1005009995244489.html?spm=a2g0o.cart.0.0.277d4ae4mkBNId&mp=1&pdp_npi=6%40dis%21EUR%21EUR%207.07%21EUR%206.79%21%21EUR%206.79%21%21%21%4021039a5b17717618790774100e5375%2112000050788672492%21ct%21DE%214400412421%21%211%210%21&gatewayAdapt=glo2deu
• Option 1 - PWM fan controller: https://de.aliexpress.com/item/1005008270023710.html?spm=a2g0o.order_list.order_list_main.222.23285c5ftMBWgP&gatewayAdapt=glo2deu
• Sealing strip 6 mm wide, 3 mm high: https://de.aliexpress.com/item/4000183342196.html?spm=a2g0o.detail.0.0.65e5yab5yab5SN&mp=1&pdp_npi=6%40dis%21EUR%21EUR%207.41%21EUR%206.89%21%21EUR%206.89%21%21%21%4021039a5b17717618332652584e5375%2112000045130708004%21ct%21DE%214400412421%21%211%210%21&gatewayAdapt=glo2deu
• 4‑pin PWM cable extension 80cm: https://de.aliexpress.com/item/1005004617556138.html?spm=a2g0o.detail.0.0.250dyJAiyJAiLW&mp=1&pdp_npi=6%40dis%21EUR%21EUR%202.12%21EUR%201.99%21%21EUR%201.99%21%21%21%40211b6a7a17717600825908612e0632%2112000029849468360%21ct%21DE%214400412421%21%211%210%21&gatewayAdapt=glo2deu
• Optional: M4 × 10 mm screws: https://de.aliexpress.com/item/33006942612.html?spm=a2g0o.order_list.order_list_main.412.23285c5ftMBWgP&gatewayAdapt=glo2deu

• Optional: M4 × 5 mm Knurled nut: https://de.aliexpress.com/item/1005003582355741.html?spm=a2g0o.order_list.order_list_main.417.23285c5ftMBWgP&gatewayAdapt=glo2deu