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by throwaway9d0291 2513 days ago
I think this is the main way to go if you care about air quality because unfortunately most consumer air quality monitors can be wildly inaccurate (i.e. detect nothing at all) even in day-to-day scenarios like making toast [0].

It's not limited to particulate matter either. You can get devices with reasonably accurate basics like temperature and humidity but as soon as you get into the actual air quality stuff like CO2, things start to fall apart. There are tons of devices that use wildly inaccurate TVOC sensors or fake their CO2 measurements (they estimate it based on H2 instead).

If you want anything remotely close to accuracy, I strongly recommend buying something that actually tells you which sensors it has inside it. Get datasheets for the sensors and check that their specs are reasonable for what you want. For example make sure that if you want to actually measure CO2 to buy something with an NDIR sensor like the Senseair S8 inside.

I wanted something I could plug into my home Prometheus/InfluxDB/Grafana setup so I bought [1] from Taobao. It lists all the sensors it uses, which are fairly good for the price. The device has a pretty simple TCP API that gives you JSON. Everything is Chinese but the measurements themselves are labelled in English and Google Translate works pretty well on the documentation.

0: https://www.sciencedaily.com/releases/2018/08/180822091022.h...

1: https://item.taobao.com/item.htm?id=550317428831

2 comments

Thanks for posting this! From the millions of air purifiers and filters that are sold, it is clear that people care about air quality in their homes. But there doesn't seem to be a good option for accurately measuring air quality.

I appreciate the option you linked and wish there was an English version of it. If you were to build a consumer product, which air quality sensors would you want in it?

For CO2, which I've researched the most out of the various things that interest me, I'd want a Senseair K30 or S8 Commercial, an Amphenol Telaire T6613 or T6713, or a CozIR-A or CozIR-LP sensor.

For low cost, I'd go with the Senseair S8 Residential. It's not fantastically accurate but it's still a "real" sensor and you can get it for $20 from China.

For other aspects of air quality, I haven't finished researching the options yet.

Thanks for sharing. I wanted to get Winsen MH-Z19B, but Senseair S8 (residential) looks like a better, more reliable option, for a DIY project. One comparison: https://www.letscontrolit.com/forum/viewtopic.php?t=3736&sta...
If you'd asked me a few days ago I'd have said that the MH-Z19B is okay on a budget but now that I know you can get an S8-0053 for $20, I don't think I can recommend it.

If it's difficult for you to get the cheap S8s for some reason though, per that thread it looks like an MH-Z19B with calibration off is a decent choice.

[1] on Aliexpress, in English, $150 : https://www.aliexpress.com/item/32759169154.html
It does have English but it's not the same thing at all: It doesn't tell you which sensors are inside it (only the CO2 sensor) and it doesn't have any kind of machine-readable interface.
"S8 is short for S8-0053 model" from description. It seems like its using sensor you mentioned.
Yes, that's why I said "only the CO2 sensor". It has other sensors but doesn't tell you what those are.

And the CO2 sensor isn't much use to me without a way to read the sensor with a computer though and the device you linked doesn't have any kind of machine-readable interface.