17 Jul
2020
17 Jul
'20
8:30 p.m.
Are you good at building electronic and mechanical gear? Want to help build
a rig to test Covid-19 face masks and materials for filtration efficiency
and breathability?
We have a plan, and can contribute some funding to get the components. But
we really *need someone to spearhead this project! If interested, please
contact me at patrikd(a)gmail.com <patrikd(a)gmail.com>*m>*, and we can sort out
the logistics...
People around the world are sewing DIY cloth masks, or buying N95 masks
from dubious suppliers with little or no quality control. There is a big
need for being able to test cloth materials and completed masks for
filtration efficiency and breathability. But the official, professional
testing gear costs around $90,000.
The Smart Air folks in Beijing built this far more accessible testing rig,
and used it to show that half of the N95 masks they sourced from different
Chinese suppliers did not meet specs:
https://smartairfilters.com/en/blog/testing-china-kn95-n95-masks-supplement…
[image: Smart-Air-N95-mask-test-setup-wind-tunnel.jpg]
The Met One GT-521 particle counter that Smart Air used in their setup
costs around $2000 new. But Adafruit sells a $45 Arduino-compatible
particle counter module <https://www.adafruit.com/product/4632> that can
measure down to 0.3 micron. A DIY version of this rig can probably be built
for around $100 total. (Alternatively, a used Met One GT-321
<https://www.ebay.com/itm/Metone-Portable-Particle-Counter-GT-321-Used-/113933228470?_trksid=p2385738.m4383.l4275.c10>
particle counter costs around $600. Or a PerfectPrime AQ9600
<https://perfectprime.com/products/aq9600> particle counter only costs
around $200 new)
The plan would be to do some research on which fans and pressure sensors to
use, order some materials, build a test rig, document the heck out of it so
others can replicate it (e.g. on Instructables or Hackaday), and start
testing mask materials - maybe in collaboration with Rachel at Ace Monster
Toys and the other folks in the Bay Area PPE group that are sewing
thousands of masks right now.
Our biggest bottleneck right now is that we need someone to lead the actual
building. I definitely want to be involved, can help with the research and
design, and am willing to put in some of my own money to buy supplies. But
I'm also still 100% Working From Home for my day job and don't have the
bandwidth right now to take this on by myself.
Help wanted!
Patrik
