Link to project website: <a href="https://senseable.mit.edu/flatburn/" rel="nofollow">https://senseable.mit.edu/flatburn/</a><p>Link to assembly guide: <a href="https://github.com/MIT-Senseable-City-Lab/OSCS/blob/main/Build/Handbook/Flatburn_%20Assembly%20Guide.pdf">https://github.com/MIT-Senseable-City-Lab/OSCS/blob/main/Bui...</a><p>Link to bill of materials: <a href="https://docs.google.com/spreadsheets/d/1-fR-0hTxHKbjaRf8DbH62WgUFVeNE4eUEsaAd-YdDYg/edit#gid=2089068555" rel="nofollow">https://docs.google.com/spreadsheets/d/1-fR-0hTxHKbjaRf8DbH6...</a><p>Naively searching for every lines of the bill of materials gives me around $300, with a handful of items being around $50 and everything else under $5. I'm sure a hobbyist could find the parts for cheaper, especially things like individuals connectors that I found for around $5. I've seen them go as low as $0.25 when bulk purchased.<p>Disclaimer: it's possible that some SKUs led me to the wrong products. I am not into electronics. I encourage you do to the same exercise before drawing conclusions.
It would be useful if headlines said "~$10", "sub $100", "sub $1000" et cetera, instead of vague terms like "low-cost".
We at AirGradient maintain popular indoor and outdoor open source air quality monitoring projects [1] and gained quite a lot of experience on air quality measurement.<p>The hard part of these projects is not connecting electronic modules and get some air quality data out of it but to ensure that the data is accurate and this is where I have some questions. The success of these kind of projects stands and falls with the trust that people have in the data it generates.<p>1) The built uses the Sensirion SPS30 PM sensor. As per Sensirion assembly guideline the maximum allowed air flow around the sensor is one meter per second. This corresponds to 3.6 km/h or 2.2 m/h. A car normally travels a multitude of this speed. I did not see anywhere in the built instructions how they manage the airflow inside the enclosure to be within this limit. In my opinion detailed airflow simulations inside the enclosure are essential.<p>2) Temperature and humidity has strong impacts on the accuracy of PM measurements and it is important that these are accounted for. This is already a challenge for stationary low cost sensors but having this sensor mounted on the roof of a car will probably give a wide vaiety of different heat exposures. I did not see how this is accounted for.<p>3) I am not sure if there are large advantages with mobile sensors compared to a high density stationary network of low cost sensors. Air pollution, especially on roads fluctuates a lot with peak times. So a measurmenet taken at 8am at a busy junction might be quite different a few hours later. How long do you keep past measurements valid for a certain location?<p>I applaud all open source projects in this space and it looks like a lot of effort went into this project so it would be great if above concerns could be addressed/clarified from somebody in the team.<p>[1] <a href="https://www.airgradient.com/open-airgradient/kits/" rel="nofollow">https://www.airgradient.com/open-airgradient/kits/</a><p>[2] <a href="https://sensirion.com/media/documents/7990F04A/616544B0/Sensirion_Particulate_Matter_AppNotes_SPS30_Mechanical_Design_and_As.pdf" rel="nofollow">https://sensirion.com/media/documents/7990F04A/616544B0/Sens...</a>
Usual disclaimer that MIT's PR dept is really effective (I've stopped paying attention them because of so much hype), and there's quite a chasm between a proof of concept and a mass-market device.
This feels like old news. Built such a thing for a german hacker initiative like 7years ago. Back then sub 50€ and still runs.<p>Data available at luftdaten.info<p><a href="https://sensor.community/de/sensors/airrohr/" rel="nofollow">https://sensor.community/de/sensors/airrohr/</a>
This sounds highly implausible for anything other than very crude and not-very-useful measurements. Quantifying air pollution is a fairly hard problem, chemically speaking. The composition of particulate matter is highly diverse as it may arise from a wide variety of sources, i.e. agricultural, industrial, wildfires, diesel engines, etc. Just looking at the particulate PM2.5/PM10, broadly speaking there's the organic carbon fraction and the inorganic metal fraction. The former is highly complex, e.g.:<p>> "The considerably increased chromatographic resolution in GC×GC [gas chromatography] allows separation of many UCM [organic carbon] compounds while the TOFMS [mass spectrometer] supplies mass spectral data of all separated compounds. However, the data sets are getting enormously complex. In a typical PM2.5 sample from Augsburg <i>more than 15,000 peaks can be detected</i>... "<p><a href="https://www.sciencedirect.com/science/article/abs/pii/S0021967303015498" rel="nofollow">https://www.sciencedirect.com/science/article/abs/pii/S00219...</a><p>Some particulate matter may have a heavy metal fraction, some may not and that's also not easy to determine (but was a major factor in leaded gasoline pollution). Here's a sample of the kind of work that has to be done to get reliable measurements:<p>> "...using quadrupole inductively coupled plasma – mass spectrometry (q-ICP-MS). We report improved measurements of key aerosol elements including Al, V, Cr, Fe, Ni, Cu, and Zn in airborne coarse particulate matter (PM10)... This technique was used to determine the elemental composition of over 150 PM10 samples collected from an industrialized region in Houston, TX."<p><a href="https://www.sciencedirect.com/science/article/abs/pii/S0003267010014522" rel="nofollow">https://www.sciencedirect.com/science/article/abs/pii/S00032...</a><p>On top of that there's nitrogen oxides and PAN, ozone, etc. The only relatively inexpensive recent innovations seem to be the use of drones to collect samples for lab analysis (would have been useful in East Palestine).<p>Getting accurate measurements of all the species involved in air pollution requires a modern analytical lab packed with equipment that costs hundreds of thousands of dollars and highly trained technicians to operate. The press release and snippets from the paper don't address such important details at all.
For those wanting a cheaper version that is small and works great. I've been using this for a while at home. It integrates nicely with home assistant.<p><a href="https://community.home-assistant.io/t/sniffer-air-quality-sensor-using-esp32-with-lcd-pmsa003-bme680/226870" rel="nofollow">https://community.home-assistant.io/t/sniffer-air-quality-se...</a><p><a href="https://github.com/kylemanna/sniffer">https://github.com/kylemanna/sniffer</a>
I don’t know if this is the device to do it, but the premise is solid: create awareness that air pollution is a real thing affecting specific areas in which <i>you</i> are breathing right now, not just an abstract bad thing that may or may not be happening somewhere to someone.
The key word -- which is missing from the PR title, but is in the paper title -- is "calibration". The novelty is there. Apparently this is a big problem due to varying humidity levels.
IKEA hack<p><a href="https://style.oversubstance.net/2021/08/diy-use-an-ikea-vindriktning-air-quality-sensor-in-home-assistant-with-esphome/" rel="nofollow">https://style.oversubstance.net/2021/08/diy-use-an-ikea-vind...</a><p>and of course previously on HN, airgradient DIY<p><a href="https://news.ycombinator.com/item?id=27124671" rel="nofollow">https://news.ycombinator.com/item?id=27124671</a><p>The more the better. Maybe one day built into every smoke detector.<p>Maybe in a decade built into your phone. Another decade in your watch.
This is a DIY open source air quality monitor starting from $67, a lot cheaper than what the article mentions: <a href="https://www.airgradient.com/open-airgradient/kits/" rel="nofollow">https://www.airgradient.com/open-airgradient/kits/</a><p>Been geeking out on AQ (air quality) lately and it’s fascinating. Market is very messy though. Few options with huge price discrepancies. Ultimately it looks like the sensors inside the fancy $300+ monitors cost a few dollars to acquire.
Large scale data collection like this is good stuff. Sure, it can look like data for data's sake, but the downstream modelling from streetscape PM2/2.5 distribution into how it gets into people is there.<p>NO levels need to be collected alongside PM2 and CO/CO2. That stuff is really bad for you.<p>Insane amounts of inner-city schools without Air conditioning depend on open windows, kids sitting inside all-day next to busy streetscapes with diesel trucks roaring by. We know what this does to people.
I had a similar DIY project, also using some Alphasense sensors, + some cheaper metaloxide ones. It was somewhat promising, but it needs long-lasting colocation studies and, after I moved to Sweden, I lost any support from the local authorities and gave up.
<a href="https://bochovj.wordpress.com/tag/air-quality/" rel="nofollow">https://bochovj.wordpress.com/tag/air-quality/</a>
Official repo:<p><a href="https://github.com/MIT-Senseable-City-Lab/OSCS">https://github.com/MIT-Senseable-City-Lab/OSCS</a>
Impressive, I’ve been wanting to build a portable version of this for a while now. It would look like a smart band but integrate environmental sensors and the users would then be aware of how their environment is affecting them. They would also have the option of contributing their data to a collective dataset.
They mentioned a NO2 sensor in the article, but then I don't see it in the BOM.<p>Was it only used for the calibration?<p>If so, that would be a shame, as I am precisely looking for an inexpensive but reliable NO2 sensor device.
How does this compare to something like an Airgradient, which you can put together for like $50? More detail about what constitutes the PM2.5 or PMn particles you're measuring?
Uh.. you can just get an Arduino, LCD module, and a Plantower PMS5003 for $35.<p>That's what I did when the air was unbreathable with an AQI ~ 900.
there is an old man in Berkeley who has made very good money for more than thirty years, designing and selling these. No, he does not want to "open source" it (I tried).