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Unrelated to this (and sorry for highjacking this topic), but just want to say a big big thank you to ladyada for founding Adafruit.

When we decided to go fully open source hardware at AirGradient, I looked at the ‘business’ models of two companies: Adafruit and Arduino.

Seeing that both worked sustainably, made our decision much easier and it was probably one of the best decisions of our life. I just talked at the Open Hardware summit in Berlin about “50 devices later: The open source hardware advantage” [1].

[1] https://2026.oshwa.org/talks/100-achim-haug/

Is it only me or are you guys also being disappointed when a very interesting article is heavily AI written?

I feel like not wanting to read it in depth, even though the topic is unique and something I like to learn more.

It’s a shame because there was probably quite some work that went into it: coming up with the topic, doing the research, polish it up etc.

I have also been using AI a lot for article writing but the last two posts I wrote I went back into handwriting. They are much less “perfect”, but they are me and 100% what I want to say and convey.

Even the imperfections matter.

Maybe like a piece of handmade furniture vs something from IKEA.

It’s actually a nice article if it wouldn’t be so obviously AI written.

In my opinion this really devalues the reputation I am having for a publication and is a pity especially in this particular case as home assistant is such a great community.

I guess for a lot of the Show HN posts, people could accuse of being Ads.

This was an honest account of my experience coding this. If you do a bit of research on our company, you might come to a different judgement. But obviously everybody is free to have their own opinions.

Mostly codex, and initially claude. I'm planning a follow up post on more details of our process.

Different strategies.

- sometimes when it’s lost, just roll back. Commit very often. Sometimes it’s getting lost on simple and easy features - very unexpectedly.

- prompt regularly to review the architecture and clean up the code, check for specific things like code repetitions, error handling etc.

- keep an eye on the code yourself. At least on the general architectural side, and review complex code areas by hand

- ask always for larger features to make a plan first. Review the plan carefully. Only when the plan is ok, ask it to start coding.

I actually think this could be the completely wrong approach.

By focusing on only one persona, you might focus on one that for reasons NOT covered in this questionnaire does not work out.

Practical example from us at AirGradient. Initially, we had a strong focus on selling air quality monitoring to schools.

Our strategy would have ticked all boxes in this article but selling to schools turned out to be extremely difficult. In our case, the problem was that decision makers are often not the people benefiting from the solution. Another reason for that persona being very difficult was that air quality is not a core competency of a school.

So I actually think that you should have a relatively broad approach because often the customer that you will be successful with you actually might not know when you start.

100% agree. It is super important to know the composition of the particles.

Unfortunately currently only super expensive instruments can measure this in real-time.

This is why I believe contextual information will become much more important in future.

Detect an indoor short PM2.5 spike around lunch time, probably a cooking event.

Detect medium elevated levels outdoor in a city in the morning and late afternoons, probably traffic related smoke.

I actually made a small tool to simulate different events that contain a quiz. Give it a try here [1].

[1] https://www.airgradient.com/air-quality-monitoring-toolkit/p...

Achim from AirGradient here. Great to see this posted.

When we first heard about this new sensor, we were quite pessimistic about its performance but have been pleasantly surprised by its performance. It is something we consider now for potential future products.

We are also currently testing the energy consumption because we believe the fanless design should make it quite efficient; but not sure how much the laser needs. So we will keep the article updated as learn more.

You can use an air purifier. The Hepa filters are effective in eliminating PM. Gases like NO2 and VOCs can be reduced with carbon filters. Make sure that your carbon filter is large and different get saturated too quickly.

Yes of course! Thanks for pointing it out. I corrected the above.

What’s important to understand is that PM2.5 is not PM2.5.

It only defines the diameter of the particles but can be composed of very different elements. From salt that dissolves in the lungs to toxic metals.

Currently it is extremely difficult to get a comprehensive understanding of the health impacts of these particles.

Much more research needs to be done to understand which particle compositions and thus what sources of air pollution (eg traffic, wildfires, factories, landfills, ports etc) have what kind of health effects.

If you are interested to see an image how different PM2.5 particle look like, have a look at the photo in this blog post that one of our in-house scientists wrote [1].

[1] https://www.airgradient.com/blog/pm25-is-not-pm25/

(Edited and replaced weight with diameter)

Achim from AirGradient here. Some thoughts on this.

Purely focusing on the display, I can see a certain logic to say: Display not working => Not recommended. And probably I chose the wrong title for this as it made the article too much focused on this aspect.

However, the main critique for me is actually the general subjective nature of the article and the lack of a systematic testing approach for the monitors. In my opinion this review should not to be called "The Best Indoor Monitors" if Wired has an intention to provide objective and a balanced assessment of indoor monitors.

Of course I am unhappy that our monitor got labelled as "Not Recommended", but the bigger picture to what extent these "Best ..." reviews do provide a fair and comprehensive assessment is in my opinion the much more important discussion that we should have.

Yes, I did not mention our outdoor monitor being featured because I don't see this as a success when I critique the whole methodology of the review.

As I mentioned above, we are working on a refresh of the indoor monitor. The display is also under discussion but so far with 10s of thousands of the indoor monitor sold, I am only aware of a single digit number of cases of a failed display.

A few thoughts from me on the discussion so far, which I find incredibly insightful. Many thanks to everyone sharing their perspectives. I truly appreciate it.

On subjective reviews: I think there's absolutely nothing wrong with reviews based primarily on an author's subjective opinion. However, such reviews should be appropriately labeled. For example, "My Favorite Air Quality Monitors" rather than "The Best Indoor Air Quality Monitors". The title sets reader expectations for objective evaluation with consistent methodology.

On the defective display: Important clarification: we did not ship a broken device. The display issue developed during the review period—this wasn't a QC failure on our part. Hardware can fail during use (as it can with any electronic device), which is exactly why we immediately offered replacement parts, a new unit, and detailed repair instructions when we learned about it.

On the tiny display and lessons learned: We're well aware that opinions on our display vary significantly, as evidenced by this discussion. Some users love it, others find it too small. We actually have differing opinions within the AirGradient team as well. We're planning a refresh of our indoor monitor next year and are currently testing around 10 different display types—including e-ink, colour OLED, touchscreens, and others. So far, we haven't found the ideal replacement, but we're planning to involve our community later this year to gather feedback on the various options.

No, this is actually the purple air indoor monitor which has no display.

Agree.

I actually tried to reach out to Louis Rossmann a few times but haven’t got a response (yet).

I think what’s most interesting is that we figured out a business model based on open source hardware that’s sustainable. Thus a win-win for the manufacturer and the customer.

Repairability was actually a feature we design into the product from the start.

Achim from AirGradient here. Good to see that my post has been submitted here. Happy to answer any questions you might have.

I spend quite a long time writing this post and it actually helped me to see the bigger picture. How much can we actually trust tech reviews?

I am already getting very interesting results from the survey I posted and already planning to write a follow up post.

I hit sent too fast on this one and added the missing part.

We went full in and not only open sourced the firmware of our air quality monitors but made it completely open source hardware, this means it includes the electronic schematics, enclosure files etc. [1]

I believe it was the single most important decision we took as a company and probably also contributed to a large part to the growth and success we are having now. It enables us to build a really strong community, and also differentiate ourselves clearly from other manufacturers that are all pretty much only offering proprietary solutions.

But I think people need to be aware that by open sourcing, they put the company on a different trajectory. For example you are basically making yourself a lot less attractive for VCs.

When I see how much other companies can get investments that help them grow faster and make more impact is the only times when I sometimes wonder if other models might have been a better option?

[1] https://www.airgradient.com/documentation/overview/

We don’t have enough experience with the SEN5x yet to give an opinion but it’s definitely a good sensor.

It might be better than the Plantower but on the other hand we know the Plantower really well now after 10s of thousands of units going through our test chamber. This allows us to tweak the Plantower to really good performance.

Can you please clarify what you mean with “Everything Presence One” and the “Pro Model”?

Hahah. Thanks for calling me!

We actually have a sample of the Bosch in our office but haven’t come along to test it yet. Maybe with this call, I will get our team onto it.

The form factor has pros and cons in my opinion. The size and lower energy consumption definitely opens new applications but the problem is that it needs a clear field of view to do the measurements.

This could in turn restrict the applicability, eg as a wearable sensor.

In general I think it’s great to see innovations in the PM sensor field but often minimizations go on costs of accuracy.

We saw that for example with the Sensirion photo acoustic CO2 SCD4x sensor that is tiny but needs more black box algorithms to compensate for certain environmental conditions that then limits the range of applications.

Great feedback. Thank you.

Achim, founder of AirGradient here.

This article is super interesting as it shows that one of the key features (showing air pollution as cigarettes equivalent) on the new AirGradient Open Source Map [1] is actually scientifically backed.

This new map app is as a central component of our Clean Air Advocates Program, building on the foundation of data generated by thousands of our open-source air quality monitors [2].

To effectively visualise the impacts of air pollution, one of the first features we aim to implement is the "cigarettes smoked equivalent" [3]. This feature will help users understand the health implications of local air quality in a tangible way, reinforcing the program's goal of empowering individuals to understand and improve their local air quality.

We already have quite a big community behind this project [4], and I would love to see more people involved. So if you are interested, please get in touch with me or just start contributing!

[1] https://github.com/airgradienthq/airgradient-map

[2] https://www.airgradient.com/

[3] https://github.com/airgradienthq/airgradient-map/issues/100

[4] https://www.airgradient.com/open-source-initiative/

Nicely produced video but two things I think make it less great.

1) The sponsorship / advertisement is artificially linked to the content of the video and makes it more like an ad for the computer. It appears like the video is optimized for ad profitability but not necessarily for bringing most value to the DIY project. Sponsorship is fine, but I would prefer it to be separate from the video content.

2) There are some elementary electronic checks missing, eg the impedance of the speakers. If the ohms not match, the amplifier might actually get damaged.

Achim, founder of AirGradient here.

Nice to wake up and see a hacker news post benefiting from our open source air monitor designs, especially with the original design that we started with so many years ago! Makes me realize how much AirGradient developed since these early days.

Did you consider linking the fan with the CO2 data and making this a demand controlled system? Like you control the speed (or just switch on / off the fan) based on CO2 levels?

I think this could have a few advantages in terms of energy savings, noise level etc.

Running a positive pressure system in my house since many years, I agree that sucking in fresh air from outside and filter it with a HEPA filter makes more sense.

You probably need to make sure you use a fan that creates enough pressure to get the air through the trickle vent as well as a filter. A duct fan might be more suitable than a PC fan for this.

Actually the real accuracy is much better, especially with optical NDIR sensors.

We do a lot of testing against reference grade sensors and typically see very good performance and reproducibility [1].

[1] https://www.airgradient.com/blog/performance-of-low-cost-co2...

It seems that there has been fundamental mistakes and overstatements in the amount of particles from brakes in much of the secondary research in the last decades.

Details: https://pubs.acs.org/doi/10.1021/acs.estlett.4c00792