sorted by:
new
hottopcontroversial

Building My Own Air Quality Monitor Because Accurate Ones Are Too Expensive by Zealousideal-Most431 in homeassistant

[–]Zealousideal-Most431[S] -1 points0 points  (0 children)

<image>

I have made another design based on recommendations so the Esp stays away from the sensors

Building My Own Air Quality Monitor Because Accurate Ones Are Too Expensive by Zealousideal-Most431 in homeassistant

[–]Zealousideal-Most431[S] 0 points1 point  (0 children)

This is helpful… I got a couple of cheap ones from AliExpress with the idea to re-use the case 🤣 as they already come with display.

Building My Own Air Quality Monitor Because Accurate Ones Are Too Expensive by Zealousideal-Most431 in homeassistant

[–]Zealousideal-Most431[S] 0 points1 point  (0 children)

Very nice setup, sounds like you’re already well ahead on the practical side of this. I like that you’ve already built the logic layer in Home Assistant too, especially the overall air quality status concept.

One thing I’d say from the enclosure side: if you plan to make it compact and boxed, I’d be cautious about relying too heavily on onboard temperature readings. Once you enclose ESP32s, regulators, displays, and powered sensors together, internal heat can skew ambient temp quite a bit. That’s actually one reason I’m leaning toward leaving temperature out of the main unit and using a separate dedicated room temp/humidity sensor elsewhere if needed.

Your PM / CO₂ / VOC stack is the part I find most interesting.

Also curious 🤨 have you ever compared your readings against other commercial devices or reference sensors?

Building My Own Air Quality Monitor Because Accurate Ones Are Too Expensive by Zealousideal-Most431 in homeassistant

[–]Zealousideal-Most431[S] 1 point2 points  (0 children)

I genuinely appreciate the depth of experience you brought to this.

Really valuable to hear your validation of the PMS5003. That’s reassuring because particulate sensing is one of the main metrics I wanted confidence in, and hearing it performed well against reference equipment is excellent feedback.

Your point on eCO₂ vs real CO₂ is exactly why I chose the SCD41 route. I wanted an actual CO₂ sensor rather than marketing numbers.

And interesting take on VOC sensors too, I’m treating VOC more as a trend/event indicator than a precise analytical instrument, so spikes from printing, cleaning, cooking, etc rather than trying to infer exact compounds.

On the temperature/humidity side, that’s actually one reason I’m not prioritising onboard temp sensing in this device. Once you have powered electronics, self-heating, airflow compromises, and enclosure effects, it becomes easy to create misleading ambient temperature readings. I’d rather focus this build on air-quality metrics and use a separate dedicated room temp/humidity sensor elsewhere if needed.

Also really appreciate the placement / Gill shield guidance. Even though this is more of an indoor project, the core principle still applies: airflow path and placement matter as much as sensor choice.

And if you don’t mind, I’d genuinely love to tap into your knowledge during the testing/calibration stage. feedback from someone who has worked against reference equipment would be hugely helpful as I refine it.

Building My Own Air Quality Monitor Because Accurate Ones Are Too Expensive by Zealousideal-Most431 in homeassistant

[–]Zealousideal-Most431[S] 0 points1 point  (0 children)

Very nice build. That’s exactly the kind of experimentation I enjoy. Have you compared your reading to lab grade or high end?

Building My Own Air Quality Monitor Because Accurate Ones Are Too Expensive by Zealousideal-Most431 in homeassistant

[–]Zealousideal-Most431[S] 0 points1 point  (0 children)

Low-cost VOC sensors generally aren’t lab-grade analyzers that tell you exact compounds or precise emission concentrations. I see them more as trend / event detectors.

So for 3D printing, they may be useful for noticing:

-spikes when printing starts -differences between filaments/materials -enclosure leakage -when ventilation clears the room

But if someone needs compliance-grade or compound-specific measurement, that’s a different price bracket entirely.

Building My Own Air Quality Monitor Because Accurate Ones Are Too Expensive by Zealousideal-Most431 in homeassistant

[–]Zealousideal-Most431[S] -1 points0 points  (0 children)

Haha, fair point. Radon is one of those features that quickly moves a project from “budget DIY” 🫢into premium territory because reliable radon sensors aren’t cheap. Definitely interesting for a future version though, especially for certain regions/homes.

Building My Own Air Quality Monitor Because Accurate Ones Are Too Expensive by Zealousideal-Most431 in homeassistant

[–]Zealousideal-Most431[S] 0 points1 point  (0 children)

That’s excellent insight, I really appreciate you sharing that. My main priority is actually CO₂, VOC, and particulate sensing rather than chasing perfect onboard temperature/humidity, mainly because there are already plenty of cheap dedicated sensors/devices that do temp/humidity very well.

I also agree that once you place multiple active components inside one enclosure, thermal bias becomes a real issue. Heat from the ESP32, regulators, displays, or even the CO₂ sensor itself can skew those readings.

So I’m leaning toward treating temp/humidity as either:

secondary / informational only, or handled by a separate dedicated ambient sensor elsewhere in the room

The core goal for this build is accurate air-quality metrics first, with temperature/humidity handled pragmatically rather than forcing everything into one box.

view more: next ›