121–130 of 218 posts
However, I'd like to point out CO_2 - there are two kinds of sensor. One of them measures volatile organic compounds and assumes that CO_2 correlates with them, and the other actually measures CO_2. The second type costs around £40 for the raw sensor - if your sensor is cheaper than that then it probably isn't actually measuring CO_2.
The main takeaway is that it takes more than I thought to keep indoor CO2 at bay, especially during winter when you have to deal with low temp/air pollution outside.
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Because like anything analog these days, they are hard to find?
I can find mechanical scales very easily in the Netherlands, but they're more expensive. On Alibaba I see that digital bathroom scales are about $2.50 and with WiFi/Bluetooth it's $6, mechanical scales are double that at $12 while also taking up more volume (more pallets and containers). With volume scale and unique designs, your own skin on the apps, and market specific packaging the margins are only going to get be…
Author here. I wrote this article a few weeks ago after discovering that a well known air quality monitor in the market that retails for more than USD 1000 actually uses a PM module that costs less than USD 20. Often people assume that the more expensive, the better but as you can see in the article this is often not the case -especially when it comes to the accuracy of the monitor. If you are looking for an open sou…
You appear to be using CC BY-NC (although it's ambiguous if that applies to the schematics/3d files or only the instructions?) which isn't an open source licence, as it violates point 6 of the open source definition. [0] Sorry to be pedantic, but it spoils an otherwise interesting looking project. [0] https://opensource.org/osd/
We also wrote a blog post about our decision to use CC BY-SA [2].
[1] https://www.airgradient.com/open-airgradient/instructions/di...
[2] https://www.airgradient.com/open-airgradient/blog/thoughts-o...
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You appear to be using CC BY-NC (although it's ambiguous if that applies to the schematics/3d files or only the instructions?) which isn't an open source licence, as it violates point 6 of the open source definition. [0] Sorry to be pedantic, but it spoils an otherwise interesting looking project. [0] https://opensource.org/osd/
We use CC BY-SA 4.0, see for example here [1] which is open-source 'compatible'. We used -for a short time NC- but not anymore. Where did you see the NC license? Maybe we forgot to update it somewhere? We also wrote a blog post about our decision to use CC BY-SA [2]. [1] https://www.airgradient.com/open-airgradient/instructions/di... [2] https://www.airgradient.com/open-airgradient/blog/thoughts-o...
It's great that you chose to switch to an open source compatible licence.
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The same is true of digital bathroom scales. In fact almost all consumer grade digital scales have “fake accuracy” built into the firmware that ensures the same exact weight shows up when you step on the scale twice in a row, even if you pick up e.g a quarter-pound weight in your hand the second time
I can recommend Xiaomi Smart Scale 2 ( not the body composition one, it's nonsense). It is very accurate and repeatable. So much so, that you can see your weight drop after you go to the toilet. It is fascinating how much one's weight fluctuates during the day (or night which is even weirder if you don't eat/drink anything!)
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We use CC BY-SA 4.0, see for example here [1] which is open-source 'compatible'. We used -for a short time NC- but not anymore. Where did you see the NC license? Maybe we forgot to update it somewhere? We also wrote a blog post about our decision to use CC BY-SA [2]. [1] https://www.airgradient.com/open-airgradient/instructions/di... [2] https://www.airgradient.com/open-airgradient/blog/thoughts-o...
It's at the bottom of the first link you posted https://www.airgradient.com/open-airgradient/instructions/di... It's great that you chose to switch to an open source compatible licence.
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While I admire the efforts of the SC-AQMD, and generally agree with the article, using R2 from a higher-end, but not quite perfect instrument, can be quite misleading, and is not a great indicator of actual sensor performance. Also, there are a lot of potential improvements in sensor tech, but instead almost everyone is relying on the same cheap sensor modules instead of innovating, which have have pretty bad deficie…
The R2 is between the tested monitor and the AQMD reference instruments (BAMs and Grimms). They also test if the two reference instruments agree with each other before calculating the correlation to the tested monitor. So I believe their testing method is quite accurate.
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The same is true of digital bathroom scales. In fact almost all consumer grade digital scales have “fake accuracy” built into the firmware that ensures the same exact weight shows up when you step on the scale twice in a row, even if you pick up e.g a quarter-pound weight in your hand the second time
I can recommend Xiaomi Smart Scale 2 ( not the body composition one, it's nonsense). It is very accurate and repeatable. So much so, that you can see your weight drop after you go to the toilet. It is fascinating how much one's weight fluctuates during the day (or night which is even weirder if you don't eat/drink anything!)
That works with my NoName NoSmart TwentyBucks Scale scales too.
The article is about PM2.5 consumer units, and I can well believe that price doesn't make much difference. However, I'd like to point out CO_2 - there are two kinds of sensor. One of them measures volatile organic compounds and assumes that CO_2 correlates with them, and the other actually measures CO_2. The second type costs around £40 for the raw sensor - if your sensor is cheaper than that then it probably isn't a…