Comment by bsmth | Hacker News Reader

Comment by bsmth | Hacker News Reader

I've been interested in trying out different air sensors for a while. I tested out some of the super cheap ones ("MQ-7" etc.) for DIY cellular iot devices. I wasn't impressed at all with the accuracy, it was more like a random number generator. I recall that pre-heating was something you needed to do with it but I've since realized it's required once for 48 hours before general use, not a two-minute warmup each time a device is powered up. Anyway the general consensus seemed to be that anything under 50EUR was a waste of money. Did anyone else have success with the cheaper sensors?

This post got me interested again in trying out something a bit more robust. I've put through an order for the kit linked in the article. Looking forward to trying it out.

The cheaper sensors detect volatile organic compounds, and assume that CO2 level correlates with that. This isn't necessarily true. BigClive tested one, and called it a party detector[0], because it was great at picking up alcohol, but not so good at detecting when a literal stream of CO2 was blasted at it.

[0] https://www.youtube.com/watch?v=D2Wq4Yg52No

I come from a remote environmental instrumentation background and it's pretty amazing where the technology has gone. I've built two of the airgradient kits, tested various relatively inexpensive sensors and compared them to professional grade sensors. While this stuff is not even close to research grade it's a fraction of the cost, $35 for NDIR CO2? Crazy to me. You could setup a few of these sensors inexpensively, do an in-situ calibration (your house, backyard, whatever), model the response and apply a correction factor to give you some pretty good results.

For homes good enough is fine so it's really cool to see these devices become more available. You'll have fun with the kit, it's super easy to use and really easy to integrate.

Thanks for ordering our air quality monitoring kit!

We use the same industry grade sensor modules that are normally in much more expensive commercial monitors. So the kit will give you very good accuracy.

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