Internal active air filter

My goal was to create an effective filter based on currently available and cheap cartridges.I chose the following parts:A quiet and effective fanfirst choice was Noctua NF-P12 redux-1700 PWM. Activated carbon filters- there are so many on the market, but I found ones that fit the design and most importantly, will last a long time with minimal loss after trimming (because they are made to measure). Activated carbon filters HEPA filters- You have a lot of choices here. Maybe you will find cheaper ones in your store because homemade robots are becoming very popular and that's a good direction for us. They must be standard iRobot Roomba 800. Installation begins with mounting brass threaded inserts M3x5x5 or