ahaucnx

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421.
by ahaucnx 5y ago
Yes. It is important to use CO2 sensors that do not have a short automatic baseline calibration like the MH-Z19 that is popular in DIY projects but calibrates every 24h. Better use a sensor like the Senseair S8 that only calibrates every 8
422.
by ahaucnx 5y ago
Yes I agree. Often there is also the dilemma if you live in a polluted area and have purifiers in the classrooms. Opening the windows will reduce CO2 but increase PM2.5. Not opening will lead to lower PM2.5 but high CO2. Here in Asia in hig
423.
by ahaucnx 5y ago
With a permanent installation you can link the sensor CO2 data with the hvac system for a demand controlled ventilation. This will allow energy savings and maintain an optimum level of CO2 in the classrooms. We often see big differences in
424.
by ahaucnx 5y ago
I recently made built instructions [1] for a WiFi enabled CO2 monitor that can be used in schools and is a great project to built together with students. It shows the current CO2 levels with a large green, yellow red LED matrix. The kit com
425.
by ahaucnx 5y ago
I think many in the hacker news community know me for our open source / open hardware air quality DIY kit [1] measuring PM2.5, CO2, Temperature and Humidity. Especially CO2 levels seems to be something of high interest, probably due to
426.
DIY CO2 Traffic Light(airgradient.com)
9 points by ahaucnx 5y ago|2 comments
427.
by ahaucnx 5y ago
You can build our DIY air quality sensor based on the Arduino SDK (fully open source / open hardware) [1]. Something that many people find useful (especially monitoring CO2 levels at home) and it comes with a nice 3d printable enclosur
428.
by ahaucnx 5y ago
The S8 is a high quality NDIR CO2 sensor often used in professional air quality monitors.
429.
by ahaucnx 5y ago
Airnow is using US AQI and not μg/m. US AQI 50 corresponds to approx. 12 μg/m.
430.
by ahaucnx 5y ago
The shipping times mentioned on the website are a bit conservative and often it is faster. We currently have kits in stock and ship within a few days of orders received. Shipping times really vary depending on destination and are hard to pr
431.
by ahaucnx 5y ago
I don't really have much experience with the PM1006K in the Ikea sensor but it is not untypical that PM sensors can get "stuck" and showing high concentrations. Sometimes it helps to blow compressed air inside to push out any
432.
by ahaucnx 5y ago
As I mentioned in the article it really depends on the length of the exposure and how you use the sensor. Yes in many places in Europe or North America, the outdoor air quality is most of the time good. However -unfortunately- there are als
433.
by ahaucnx 5y ago
I am not aware of a good and low-cost wifi connected sensor but as I mentioned it is relatively easy to build one yourself. If you don't want to buld yourself, there are a few relatively good non-connected PM 2.5 sensors for example th
434.
by ahaucnx 5y ago
I can recommed the Plantower 5003 PM sensor. Plantower also has smaller ones, e.g. 7003 or A003 but we get the best (most accurate and stable) readings from the 5003 model. We also experienced with more expensive ones e.g. from Sensirion bu
435.
by ahaucnx 5y ago
It is actually pretty easy to build a much more accurate air quality sensor with the Plantower PM2.5 module as a base and a Wemos D1 mini as WiFi connected MCU. We have build instructions on our website on how to do it [1] + a nice 3D print
436.
by ahaucnx 5y ago
Author here. I forgot to mention: With a Wemos D1 mini (ESP8266) MCU that costs around USD 2.00, you can pretty easily make the Vindriktning WiFi connected and get the data to a backend [1]. You just need to solder three wires, and there is
437.
Ikea Vindriktning Air Quality Sensor Review and Accuracy(airgradient.com)
495 points by ahaucnx 5y ago|163 comments
438.
by ahaucnx 5y ago
I got your message. Will reply to all messages later tonight.
439.
by ahaucnx 5y ago
Yes, often when you seal your house to keep PM2.5 low, your CO2 values go up. We measures this in classrooms [1] and I also wrote about the benefits of positive pressure systems to have near zero PM2.5 and low CO2 at the same time [2] even
440.
by ahaucnx 5y ago
When I solder, PM2.5 goes into very unhealthy territory. There are solder smoke absorbers with carbon filters that I would recommend to use.
441.
by ahaucnx 5y ago
We are based in Thailand. Normally it takes around 3 weeks to arrive.
442.
by ahaucnx 5y ago
We are based in Northern Thailand which is impacted by seasonal wildfires with very high levels of PM2.5. AirGradient originally developed out of our desire to help our school to manage the air quality during this time of the year more effe
443.
by ahaucnx 5y ago
We also had issues with the PMSA003. Better use the PMS5003 that is code compatible and has a better reliability.
444.
by ahaucnx 5y ago
Our main product is a platform for indoor air quality monitoring targeting schools [1] and offices. We have a professional sensor but also the open source/open hardware version that can be connected to our platform. Alternatively you c
445.
by ahaucnx 5y ago
Nice project! How was your experience with the PMSA003? We used it before but believe that the PMS5003 has more stable readings and a longer life time.
446.
by ahaucnx 5y ago
Sometimes even the loose estimates are totally off because most of the time the eCO2 correlates with the TVOC measurement. For example I triggered a TVOC sensor with suncream smell in a very low CO2 room and the CO2 wenth through the roof.
447.
by ahaucnx 5y ago
Yes the senseair S8 is very reliable. Our professional air quality sensor uses the same CO2 sensor and we have hundreds of them deployed without a single one failing so far. Only need to keep in mind that the baseline calibration sometimes
448.
by ahaucnx 5y ago
Hi, founder of AirGradient here. Great to see that somebody submitted our open source DIY sensor instructions here! As last time I am more than happy to send free PCBs to anybody who wants to build this sensor. It makes the build much easie
449.
by ahaucnx 5y ago
Please send me a message through the orange contact button on the webpage.
450.
by ahaucnx 5y ago
Yes, sometimes some components are not available for all countries. Just search for the same sensor on aliexpress. There are many vendors for the same sensor. Some will ship to the US.

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