Powered Air Purifying Respirator (PAPR) with hearing protection

This feels a bit like inception.. I liked this design, which was in turn based on this design, however I had some issues with both:

Some of the parts were not available in Germany
Both did not list any data about air flow and since this is about better health, I wanted to make sure it is a suitable alternative to the original Versaflo respirator.
The thing by PatriotDesigns required a lot of support and cleanup on the main body
I did not like the belt attachment standing out
Neither had hearing protection attached

The original thing said any 97x97x33 mm turbo blower fan will do, but when I ordered one and a pwm controller, I noticed two things: The controller did not work as it should. On 100%, it worked, but as soon as I turned it down just a bit, the fan would go off. But as I found out later, the fan didn't have enough air flow anyway.

Just for reference, DO NOT BUY THESE, they did not work:

Both of these have been designed for 2 pins only. Maybe the fan did not support PWM control, but all PWM Fans I know (from PCs) have at least 3 pins, I think.

After that, I bought a different fan with 4 pins and a controller with 4 pin output as well, which worked fine. These work:

As you can see in the specs, the later one is also a much stronger fan and after I bought myself a TR-971 (the official way to measure air flow on the versaflo device), I was able to test that the first fan did not have enough air flow, while the second one has more than enough. If you find a fan that is in between those two fans, it might work.

For the hearing protection, I bought 3M Peltor X5P3E, which were officially recommended, only to notice afterwards, that they need an adapter to be mounted on the M-207 and that adapter could not be bought in any shop that is available for normal customers (without buying more than 10 pairs), so I designed an adapter as well.

All parts used:

3M Versaflo M-207 face shield [~218€, prices vary a lot depending on the shop, got mine on ebay]
3M 3M BT-30 breathing tube [~22€, prices vary a lot depending on the shop, got mine on ebay]
Haofy Haofyyn93tagihb504 / SHLFBFB1012EHK302 12V 2.94 A / 21,6 W, 71mmH₂O air pressure, 46 CFM air flow [~14€]
RUNCCI-YUN R1136 / 4 pin [~7 € for 2]
5.5MM x 2.1MM plugs cable [~11€ for 2]
5.5MM x 2.1MM sockets [~5€ for 6]
Roomba 800 filters [~10€ for 6]
input voltage cable
some self-adhesive foam (2mm thickness, compresses to 0.5mm) for to the part where the fan connects to the outlet
4 wafer-head M4 screws, long enough to go through the two smaller parts and at least half through the main body
epoxy glue or similar

Optional parts:

an extra 2-pin connector I had laying around for the voltage input
2 pins for the voltage input, I used an old needle pin, soldered it to the board, then clipped it to length
3M Peltor X5P3E for helmets [~37€]
4 wood screws (wafer-head), two short M4 screws (countersunk), two longer M4 screws (wafer-head), 2 washers and 4 M4 nuts to mount the hearing protection
TR-971 for measuring air flow [~19 €, used on ebay]
"Tactical belt" for easy attachment [~15€]
PA 14.4-18 LED-USB / 600288000 [~29€] for using CAS batteries.

So all in all ~400 € for a setup that costs ~1300 € in its official set (admittedly, I already have the batteries and charger present). That is a LOT of money, but hopefully more affordable for us non-profit DIY woodworkers.