20 ms·

AirGradient Open Source Air Quality Monitor for CO2 and PM2.5 Measurements

557 points by ahaucnx 4y ago

ahaucnx 4y ago
This is an updated version of our DIY air quality monitor that now includes a configuration button and some other PCB improvements around the I2C bus. It has also pin breakouts so you can easily add additional sensors if required. Hardware and software are both open source and can easily be adjusted.
- smcleod 4y ago
  Nice! Great work making it open source!
- Youden 4y ago
  Was the decision to use pin headers instead of SMD components a conscious choice? For the particulate sensors it's unavoidable but you can use Sensirion's SCD4X series for CO2, just about any VOC chip you want, and an ESP32 module instead of dev board. It should be substantially cheaper overall since the components can be ordered in bulk and the only assembly needed would be the particulate sensor. I've been meaning to get around to it myself but I still haven't settled on how to power it. I'm really tempted to try stuffing it full of giant batteries so that it can run for at least around a year without a cable.
  - ahaucnx 4y ago
    Most people find it easier to solder through holes than SMD. We use SMD in our commercial product. We are testing the SCD4x and like it so far. It might be a future option.
    - Youden 4y ago
      I guess what I'm asking is does it need to be hand-solderable? With places like JLCPCB offering cheap SMD assembly, SMD boards are still accessible to hobbyists.
      - mardifoufs 4y ago
        I though JLPCB only assembled components that are available in their catalogue. If they don't have the part you need, you'll have to hand assemble it. These are pretty niche components, with odd footprints and size so I'd be surprised if assembly was available.
        Youden 4y ago
        You can have them order parts that are available at Mouser, Digikey and the other parts vendors. They have the SCD41 [0], SGP41 [1] and a variety of ESP32 modules (e.g. [2]) in their catalogue. The preorder prices can be a bit out of whack but they'll correct them when they actually buy the part. [0]: https://jlcpcb.com/partdetail/Sensirion-SCD41_DR2/C3659294 https://jlcpcb.com/partdetail/Sensirion-SCD41_DR2/C3659294 [1]: https://jlcpcb.com/partdetail/Sensirion-SGP41_DR4/C3659325 https://jlcpcb.com/partdetail/Sensirion-SGP41_DR4/C3659325 [2]: https://jlcpcb.com/partdetail/EspressifSystems-ESP32_S2_MINI_1N4/C2847294 https://jlcpcb.com/partdetail/EspressifSystems-ESP32_S2_MINI...
  - comboy 4y ago
    If you want continuous measurement, battery is pretty much not an option, PM2.5 will use a small fan, so even at 30mA it's 30 * 24 * 365 so for a year you need 262,800mAh battery, it's a different voltage but to put it in context your laptop is likely under 10,000mAh. If you only need to take measurements say every 30mins then sure, but then either you worry about sending it somewhere and receiving it or you need to use additional battery power for displaying it.
- aikinai 4y ago
  Is there any way to checkout without PayPal? I was mysteriously banned a few years ago with no details and no recourse. And I don’t see an option to just pass through a credit card without logging in. Edit: Never mind! I found out tapping the credit card logo worked to do a pass through payment without logging into PayPal. Purchased! And thanks for supporting international shipping too!
  - ahaucnx 4y ago
    I think you should be able to just pay with credit card. If you have problems please contact us through the support form.
deleted 4y ago
[deleted]
edge17 4y ago
Just out of curiousity, what are the equivalent commercial products in this space?
- ahaucnx 4y ago
  We also offer a fully certified commercial product (AirGradient ONE) focusing on B2B (Offices, Schools). Then you have monitors from other companies e.g. Awair, AirThings, Kaiterra, Air Visual etc measuring similar air quality parameters. We try to set us apart by promoting open data standards, clear data ownership, long lasting products that are easy to repair and maintain. More details on our main website [1]. [1] https://www.airgradient.com/ https://www.airgradient.com/
- wallflower 4y ago
  The IQAir is very nice. There is also the Purple Air monitor. https://www.iqair.com/us/air-quality-monitors https://www.iqair.com/us/air-quality-monitors https://www.purpleair.com https://www.purpleair.com
  - erinnh 4y ago
    Totally not a judgement about the quality of it, but it amazes me how the IQAir is only supported via Cloud. Even for this really local information I need to contact some Cloud to be able to get the information into my smart home. This stuff annoys me a lot.
    - wodenokoto 4y ago
      I believe this is to support their pollution maps and pollution forecasts. Which makes the high price of the product odd to me.
    - ahaucnx 4y ago
      Yes unfortuntately we see a clear trend among other companies towards walled gardens, closed data and forcing people into subscriptions. We at AirGradient do not support this development and made very clear statements on our website.
Tempest1981 4y ago
I have a handheld $65 TVOC meter, but it's tricky to get repeatable measurements. It needs 5-10 minutes to warm up, but then the reading jump around almost 2x. It has 4 digits of resolution, but 1 digit of accuracy? Regardless, indoor TVOC levels increase significantly over 2-3 days. Then opening the windows brings them back down. Not sure if that's normal. (TVOC = Total volatile organic compounds) Any recommendations for quality sensors?
- parker_mountain 4y ago
  FWIW, TVOCs can collect together and move around in "waves", your indoor air is not just one big evenly distributed "soup". The sensors also have lots of factors that affect them, such as humidity - you can usually find more info in the docs for the sensor part. A better approach would be to sample consistently and use that to build a graph showing TVOC ppm over time.
- ahaucnx 4y ago
  Compared to CO2 and PM measurements, TVOCs are the most difficult to measure because they encompass a wide range of chemicals that trigger the sensor. Some are very harmful, e.g. aggressive paint and others (hopefully) harmless like sunscreen. Both trigger the sensor. Additionally the sensors are only showing you correct absolute levels in lab conditions, e.g. using ethanol at a specific temperature and humidity. So in real environments, the absolute values are pretty useless. We now use a newer generation of TVOC senor e.g. the SGP41 that is more index based and eliminates the issue of the absolute values. We also observe that temperature and humidity can influence the TVOC measurements. All in all, TVOC is good to detect spikes and check what is causing these, e.g. use of aggressive cleaning chemicals. However the absolute levels in e.g. ppb should better be ignored. Yes, it is normal that fresh air flushes out chemicals and you can see this improvement. We do like the SGP4x series from Sensirion for TVOC sensors.
  - drakenot 4y ago
    Are they accurate enough for me to ensure I’m keeping VOC levels down while 3D printing different materials?
kayson 4y ago
Wish I had seen this before I bought all the constituent parts on sparkfun! Though I do have some concerns about the accuracy of the PM2.5 sensor (mainly because the data sheet isn't exceptionally clear).I ended up getting the Sensirion equivalent over this one even though its quite pricey. Every all-in-one air quality monitor I've seen except one omit some fairly important metrics - NO2 and hydrogen sulfides. I'm guessing it's because the sensors are extremely expensive (I got quotes for $90+/ea from one vendor). I ended up finding a startup, SPEC Sensors, that has much cheaper screen-printed sensors, and if their data sheets are to be believed, they're more than sufficient.
- ahaucnx 4y ago
  We have made very good experience with the Plantower PMS5003 PM sensor and thousands of them went through our test chamber. The plantower has also shown one of the best accuracies for low-cost sensors compared to reference stations in various studies. I agree that the data sheets from Plantower are not great. Unfortuntately this is often the case from Chinese manufacturers.
  - comboy 4y ago
    I second Plantower (I've only used a few PMS7003), it allows you to build a really high quality sensor while being really a beginner project using some arduino and LCD. Note that this is only for particulates in the air. Btw, why thousands? And any reasons for not using CCS811 for TVOC and HDC1080 for temp while you're at it? Sounds like you have tons of experience and it's not easy to find reviews which properly test these.
    - ahaucnx 4y ago
      No specific reasons other than that we are pretty happy with the quality from Sensirion and thus like to use their sensors.
  - kayson 4y ago
    That's good to know! Have you published your testing results anywhere?
jph 4y ago
This is super-useful. The TVOC / NOx module is especially compelling. Can I purchase it pre-soldered? I do see your commercial offering (AirGradient ONE) and I'd like to buy that for my office. How does a typical consumer purchase one online?
- upon_drumhead 4y ago
  They have pre-soldered kits in their store, which took me a hot minute to actually find. https://www.airgradient.com/open-airgradient/shop/ https://www.airgradient.com/open-airgradient/shop/
  - ahaucnx 4y ago
    The presoldered kit also comes already pre-flashed and you can literally build it in 5-10 minutes. Just need to plug in the sensors, one cable and screw it together.
pigtailgirl 4y ago
-- live in seoul - air quality is sometimes "unbreathable" - using AirIQ api for smart home alert - https://www.iqair.com/us/air-pollution-data-api https://www.iqair.com/us/air-pollution-data-api --
maweki 4y ago
Is it common for the HN audience to be able to fabricate their own PCBs? I believe none of my local hacker spaces have fabrication facilities. Whenever I see that, it means having to pay somebody quite a bit instead of do it yourself.
- Kuinox 4y ago
  I built one. But without PCB. I just used wires and soldered it.
- idiotsecant 4y ago
  You can make your own PCBs quite easily with cheap chemicals, a laser printer, and some tubs to agitate the mixture. It's a bad idea though, when you can design them and get them made online incredibly cheaply.
- aidenn0 4y ago
  I haven't had any made in a while but last time I got 2 index-card sized PCBs with silk-screen and solder mask for under $40 after shipping.
- dgacmu 4y ago
  There are some home-brewable ways for single layer boards, particularly one sided -- you can do the old school copper board + mask + etch with something like ferric chloride. It's pretty easy but you do want to be careful as the chemicals are a bit nasty. Newer school is to print the mask and transfer using a laminator. You can also physically etch with a milling machine. It's a bit more expensive but low startup cost if you already have a small cnc mill. You probably have access to one at a maker space. That's most likely the easiest way to go.
- jazzyjackson 4y ago
  I guess I wouldn't say common - but hackerspaces and especially fablabs will often have a Roland CNC machine capable of carving PCBs out of copper-coated-fiberglass - but once you go through all that (paying for a couple broken 1/64" routing bits as you learn to use the machine...) it starts to make sense to pay $5 per square inch at oshpark
RobotToaster 4y ago
It isn't open source as it's under a NC licence, which restricts the field of endeavour. https://www.oshwa.org/faq/#non-commercial https://www.oshwa.org/faq/#non-commercial https://opensource.org/osd https://opensource.org/osd
- simondotau 4y ago
  No matter how much they wish it were otherwise, OSI doesn't get to dictate what "open source" means. It's not their trademark. The term existed before they did. And equally as importantly, the words open and source existed before they did. The source for AirGradient is not closed. It is open.
  - RobotToaster 4y ago
    Looking again there aren't even any source files available for the PCB at all, only gerber files, which are purely manufacturing files.
patja 4y ago
A project I did to make CO2 monitors with a Sensiron SCD41 sensor and Adafruit MagTag e-ink module: https://www.printables.com/model/121265-salud-co2-monitor https://www.printables.com/model/121265-salud-co2-monitor
crazygringo 4y ago
This is tangential, but is anyone aware of a live outdoor CO2 levels map? I've never been able to find one anywhere. Because outdoor levels seem to vary significantly in a kind of 400-600 range, and it's impossible to calibrate a sensor outside without a reference point. On a windy winter day you can probably assume it's close to the global ~414, but on a muggy still summer day my sensors usually read significantly higher when holding them outdoors.
- namibj 4y ago
  You can use a chemical CO2 scrubber (e.g., bubbling air through a saturated solution of calcium hydroxide) to get a rather stable/repeatable sub-ambient reference to calibrate the sensor with. An aquarium bubbler , or rather two, should be easy to plumb to a CO2 sensor. Just skip the water bath for one of them. The calcium hydroxide is sold as "hydrated lime" and needs to just be stored isolated from CO2, and is mildly basic, so will slowly corrode your fingers (wash after touching, don't get any in your eyes). Shouldn't even need gloves for this usecase, where one occasionally swaps the water and sediment for fresh stuff. Btw, the waste, after soaking CO2, is just harmless limestone. Sprinkle around somewhat to make it a thin layer to ensure it all converts soon.
- keenanj 4y ago
  This is a plug for my non-profit building an open-source version of exactly that: ribbitnetwork.org. Our society deserves to have a publicly available map of outdoor emissions. There are lots of hard science and data analysis questions to solve in order to get there with reliable and cheap sensors, but I think it’s a journey worth going on. We’re on discord and GitHub if anyone wants to come build with us.
  - crazygringo 4y ago
    Thank you! That's exactly the kind of thing I was looking for. I've been utterly baffled by how atmospheric CO2 is one of the very top issues of our time, and yet... I can get live temperature, humidity, and things like PM2.5, PM10, NO2, O3, etc... but not CO2. Since you're in this area, do you have any insight as to why? There are thousands of official air quality monitors used all over the world for calculating AQI and similar. Why did they skip CO2? Is there something inherently difficult or inaccurate about measuring it, is its short-term variation simply seen as irrelevant to health and not worth studying, or is there a political fear that live monitoring might somehow become ammunition for climate change deniers, along the lines of every winter blizzard leading to some people taunting "where's your global warming now?" The US government measures CO2 at the Mauna Loa Observatory in Hawaii... and seemingly nowhere else?
arriu 4y ago
How does this compare to something like the Aranet4 module?
- ahaucnx 4y ago
  It should give very similar results. As far as I know the Aranet also uses a CO2 Sensor from Senseair.
  - thadk 4y ago
    It appears to be this $60 Senseair Sunrise however: https://sensormaestros.com/products/sensor/gas/co2/senseair-sunrise/ https://sensormaestros.com/products/sensor/gas/co2/senseair-... https://senseair.com/news/customer-cases/aranet4-senseair-sunrise-inside/ https://senseair.com/news/customer-cases/aranet4-senseair-su...
aedocw 4y ago
For folks who want to do something similar (no CO2 measure, and possibly less accurate) for far less per sensor, you can easily connect an ESP8266 ($5) to an IKEA VINDRIKTNING ($16) air quality sensor[1]. Stick a AM2302 ($7) on the outside and you get PM2.5, temperature and humidity for about $30. [1]: https://style.oversubstance.net/2021/08/diy-use-an-ikea-vindriktning-air-quality-sensor-in-home-assistant-with-esphome/ https://style.oversubstance.net/2021/08/diy-use-an-ikea-vind...
- M3L0NM4N 4y ago
  I will note though, CO2 measure indoors can be very valuable. Higher levels of CO2 result in less brain function, as shown by this Tom Scott video: https://youtu.be/1Nh_vxpycEA https://youtu.be/1Nh_vxpycEA
  - reeckoh 4y ago
    They can also be a canary for other issues, like mold accumulation.
- PaulBGD_ 4y ago
  I have both a modded VINDRIKTNING and the airgradient, imo the airgradient is worth it if you want everything in one package. More accurate than the ikea, a nice screen/case, and you don’t have to strap a humidity sensor to the outside. Plus CO2 is great, more people need CO2 detectors.
- deleted 4y ago
  [deleted]
- jve 4y ago
  Did just that by following that particular tutorial. Didn't expect accuracy, just following how air quality changes when baking, turning on humidifier, etc. However now my VINDRIKTNING shows red with MAX reading all the time - I suppose not to be placed in the kitchen - some sticky oil grease landed on the sensor.
pfyy 4y ago
We made a small co2 sensor based on the sensirion scd30 and m5 stack. If you want a portable sensor with battery and display, you might be interested. Source code is on https://github.com/smoca-ag/m5stack_co2_sensor https://github.com/smoca-ag/m5stack_co2_sensor
pppone 4y ago
I would recommend checking out the AQ-SPEC program [1]. They do quite comprehensive tests on low-cost air quality sensors. My side project with a few friends [2] chose to use the Sensirion SPS30 [3] for our portable PM2.5 monitor. As mentioned by others, it's a bit more expensive than the PMS5003 used by AirGradient, but we preferred its documentation, company reputation, and form factor at the time of choosing (2019). The PMS5003 is perfectly capable, and has demonstrated good success with many projects/companies using the sensor (e.g. PurpleAir). However, a quick search suggests there are some issues with a recent batch of these sensors [4]. [1]: https://www.aqmd.gov/aq-spec/sensors https://www.aqmd.gov/aq-spec/sensors [2]: https://www.open-seneca.org/ https://www.open-seneca.org/ [3]: https://sensirion.com/products/catalog/SPS30/ https://sensirion.com/products/catalog/SPS30/ [4]: https://community.purpleair.com/t/new-version-of-plantower-pms5003/288 https://community.purpleair.com/t/new-version-of-plantower-p...
- newman314 4y ago
  Your site does not appear to have pricing for your kit based on brief browsing.
  - chubbnix 4y ago
    They are about $50 from my search which is about 5x more than the plantower pm2.5 sensors. There is a big difference in documentation and that issue with the new MCU on the plantower units is concerning since they all have the same markings and housing when purchased.
    - pppone 4y ago
      At volume, the SPS30 gets down to ~$30 a piece. Their newest sensors (SEN5X) offer similar specs, and are about $25 per single unit, or $15 a piece at volume for the cheapest variant. The more expensive variant include integrated T/RH monitoring, which is very handy for humidity corrections for this type of PM2.5 sensing.
  - pppone 4y ago
    Sadly not yet. Since this is more of a voluntary commitment amongst my friends and I (we're in the process of finishing our PhDs), we lack the human-power to take the product to market at the moment.
dragontamer 4y ago
Each time I see these, I feel a bit weird because they all rely upon a specific sensor, and the software / electronics is barely above beginner level. A PM2.5 sensor is based off of infrared LEDs and photodiodes. CO2 however is harder for me to understand. Does anyone know how that works? Temperature is easy: just a calibrated thermistor. Humidity: I dunno and am also curious. -------- It's be a lot more comfortable for me to call this open source if the sensors actually gave design control to the engineer, more so than just assembly.
- breput 4y ago
  The Senseair S8 CO₂ sensor[0] used in this project also uses an infrared LED and works on the principal that CO₂ absorbs certain frequencies of light. So if you know the brightness of the LED and the volume of air between it and the sensor, you can calculate the amount of CO₂ by comparing the expected vs. received light intensity. [0] https://rmtplusstoragesenseair.blob.core.windows.net/docs/publicerat/PSP126.pdf https://rmtplusstoragesenseair.blob.core.windows.net/docs/pu...
  - dragontamer 4y ago
    Good to know. So methinks that a CO2 sensor would have to be based off of multiple LEDs + Photodiodes, to measure the absorbed light at _different_ frequencies. (LEDs and Photodiodes typically are only active at one frequency: such as 900nm or 700nm). If "all" frequencies are deflected, its PM2.5 (some particle got in the way of the measurement). If "some" frequencies are deflected, then its CO2. ---------- The question after that comes down to calibration and test data. Is there an easy way to create CO2 density and/or PM2.5 particles of a certain density? --------- There's a big difference. 1. Photodiodes and LEDs are extremely common parts manufactured by a wide variety of companies around the world. By tying yourself to Photodiodes/LEDs, you are less tied to any particular company. 2. Photodiodes and LEDs are well under 10-cents each. Though some more carefully calibrated ones / specialty ones may reach as high as $1 to $2.
    - breput 4y ago
      > (LEDs and Photodiodes typically are only active at one frequency: such as 900nm or 700nm). That's not entirely correct. The spec sheet for the LED will give an intensity vs. wavelength chart, which depending on the LED can be 10s to 100s of nanometers wide. As long as the source LED has a sufficiently bright output in one of the CO₂ absorption bands, it doesn't have to be exactly tuned like a laser. NDIR is the technology used in most consumer-grade CO₂ sensors: https://en.wikipedia.org/wiki/Nondispersive_infrared_sensor https://en.wikipedia.org/wiki/Nondispersive_infrared_sensor
1270018080 4y ago
Does anyone know of air quality monitors that check for NO2 as well as CO2?
- slawwwc 4y ago
  Air-Q does both. Looks interested, but I don't know much about the quality of their products. https://en.air-q.com/produktvarianten https://en.air-q.com/produktvarianten
deleted 4y ago
[deleted]
pbronez 4y ago
Anyone know how hard it would be to convert this from USB-C power & wifi connectivity to PoE for power + data? TI has PoE chips for around $4, but I don’t know enough about electrical engineering to figure out how to swap that into this design. https://www.ti.com/product/TPS23861 https://www.ti.com/product/TPS23861
- pbronez 4y ago
  Looks like you can get a PoE to USB-C adapter for $35: Revotech PoE to Type-C Adapter Converter, Convert POE to Output 5V/2.4A USB C with Ethernet, IEEE802.3af with 10/100Mbps , Wired Broadband and PD Charging for Smart Phone/Tablet, Plug and Play (P2C5V) https://a.co/d/7320MNa https://a.co/d/7320MNa Wonder how complex it is to access the network this way. If you have to modify the USB implementation you may as well skip the adapter and add an RJ45 + internal PoE chip…
NikolaNovak 4y ago
Open source diy is wonderful. But is there a reliable trustworthy monitor that can just... Be bought? A box that will reliably tell me what's the carbon dioxide carbon monoxide dust allergens volatile compounds? Am I possibly being greedy and I need several konitors (I wouldn't have an issue with that)? Every review I check for any consumer accessible device seems to indicate they're inaccurate, miscalibrated, or downright deceptive :-(
- ahaucnx 4y ago
  PM, CO2, temperature and humidity can be fairly accurately measured with consumer monitors provided they use good sensors. You can check if the monitor is RESET AIR certified which is an independent and 3rd party test against reference devices. https://www.reset.build/directory/monitors/air https://www.reset.build/directory/monitors/air
- Forge36 4y ago
  I spent $30 on one and $20 on another. They're "close enough" and I could connect them to home assistant. The reviews suggests the CO2 is off by 100 ppm. I've only seen VOC measurable when it's in my garage. It depends on your purpose.
- tomaskafka 4y ago
  Anything under $60 doesn't have a 'real' CO2 sensor. One of the good budget ones is Cleargrass Air Monitor.
  - s0rce 4y ago
    You can diy for under 60 with a photoacoustic SCD41.
- karmelapple 4y ago
  The Aranet has worked well for me, and I think is calibrated well and works smoothly. It’s not the cheapest though, but I haven’t recharged it in over a year… almost two years now! https://a.co/d/9o1Qvzb https://a.co/d/9o1Qvzb
sc00ty 4y ago
I ordered two DIY pro kits (with the TVOC sensors) earlier this month and went to start working on them yesterday. After flashing the firmware, neither one would create a hotspot for me to connect to. Looking at them and doing some googling, i found they include knock-off Wemos D1 minis (labeled "mimi"). It looks like they're aware there are Wi-Fi issues, but the chips are still being used [0][1]. I sent in an email yesterday but I'm not expecting a response until at least tomorrow. [0]: https://www.airgradient.com/open-airgradient/blog/d1-mimi/ https://www.airgradient.com/open-airgradient/blog/d1-mimi/ [1]: https://forum.airgradient.com/t/issues-with-new-dyi-pro-presoldered-kit/414/22 https://forum.airgradient.com/t/issues-with-new-dyi-pro-pres...
- ahaucnx 4y ago
  Customer support will be in office tomorrow and we are sending a free replacement to all customers that have been impacted by a non working D1. The "Mimi" version should not have the problem and we found it to be very stable and it is currently our default version. More information here: https://www.airgradient.com/open-airgradient/blog/d1-mimi/ https://www.airgradient.com/open-airgradient/blog/d1-mimi/
pax 4y ago
Can AirGradient be made to contribute to https://sensor.community/ https://sensor.community/ or https://openaq.org https://openaq.org data streams? Or anything similar?
- ahaucnx 4y ago
  Yes very much. We are in touch with OpenAQ on this matter.
mastax 4y ago
I bought one of the DIY Pro kits and put it together. I liked it overall. I think the kit is a good value, it's convenient to get everything all together, and the injection molded case is nice. The included software and cloud dashboard are convenient and functional. There are some less good parts, though: - The instructions aren't great, but I can't remember what I had trouble with specifically. - The included screws for the case are tiny, soft, and aren't self tapping. I never got them in all the way and gave up on them after the first disassembly. The USB power cable sort-of holds the clamshell together without them. - I had issues with the reliability of the connection to the I2C sensors, especially after adding the SGP30. Reducing the speed to 100kHz helped somewhat but made the display update slowly. I never got the SHT3x temperature sensor to work reliably in the bottom corner position, so I moved it to the open top spot. I did try out various levels of I2C pull-up and removed redundant pull-ups from the modules that came with them installed. I think part of the problem is the loose fit of the included pin headers, soldering the sensors directly may help. - The temperature sensor always reads high by about 5-10 degrees F, even when installed in the recommended far corner position. I tried mounting the airgradient vertically to try to induce a draft to clear out the generated heat but that didn't help. I could try to calibrate it but I doubt it's a simple offset. - The dashboard is basic, had some annoying bugs, and they want you to pay for it. I can't remember specifically what I disliked because I replaced the firmware with EspHome long ago and set up a grafana dashboard to monitor it.
- ahaucnx 4y ago
  Thank you for your feedback. With the new version (3.7) that is also now sold as the updated kit we have addressed most of these issues. - we now supply stainless steel torx screws including screw driver - we have now the SGP41 AirGradient module in our shop that has no pull up resistors and works very stable - we redesigned the i2c circuit which now runs completely on 3.3v - so far we never charged a DIYer for our dashboard but might do so at a reasonable price in future if our server costs rise. We continue fixing issues (software and hardware) that come up in our forum and are dedicated to ensure we deliver a high quality kit.
  - runjake 4y ago
edge17 4y ago
If I live next to a construction site, would something like this provide some guidance in terms if whether I should be doing more to clean up the air in my home?
- ahaucnx 4y ago
  The PM sensor will easily pick up the dust from the construction site and you will probably notice changes in wind direction as well.
- harrydehal 4y ago
  I run an indoor sensor from a different company and it definitely allows me to measure whenever the neighbors are doing yardwork, or there's a fire down the street, etc. My sensor is indoor, but I am curious about picking up an outdoor sensor to see if I can find any long-term correlation between a train passing and increase in emissions.
unclekev 4y ago
Anyone here using/found a decent Air Quality sensors that is plug and play with Home Assistant?
- sunsetMurk 4y ago
  I use a 'LEVOIT air purifier'[1], and it has a PM2.5 sensor that works w/ Home Assistant out of the box through the VeSync integration [2]. 1- https://smile.amazon.com/gp/product/B08L73QL1V https://smile.amazon.com/gp/product/B08L73QL1V 2- https://www.home-assistant.io/integrations/vesync/ https://www.home-assistant.io/integrations/vesync/
- davidrhunt 4y ago
  I struggled with the same search and ended up getting the AirGradient DIY Pro Kit Pre-Soldered. Not quite plug and play but the steps to get it up and running are fairly straightforward. Just plug parts in, drop some firmware on, and go. Curious what other suggestions are out there because I would still like something simpler! https://www.airgradient.com/open-airgradient/shop/#!/DIY-Pro-Kit-Pre-Soldered/p/476627519/category=0 https://www.airgradient.com/open-airgradient/shop/#!/DIY-Pro...
sytelus 4y ago
On a side note, Amazon's one of the least known great product is smart air quality monitor for under $100: https://www.amazon.com/Introducing-Amazon-Smart-Quality-Monitor/dp/B08W8KS8D3/ https://www.amazon.com/Introducing-Amazon-Smart-Quality-Moni...
- ycombinatornews 4y ago
  Doesn’t measure CO2. Just CO
hrez 4y ago
If you're like me and only looking for CO2 monitor, here is a short story. I was researching all the sensors and kits and was narrowing down on AirGradient actually. Per my research the best last gen CO2 sensors are from swiss Sensirion SCD4x series. So I started looking how to build something on it etc. While poking around, by pure chance I saw that Sensirion makes SCD4x-CO2-Gadget which is SCD41 sensor with LED indicator and BLE and powered by USB the size of flash drive. https://sensirion.com/products/catalog/SCD4x-CO2-Gadget/ https://sensirion.com/products/catalog/SCD4x-CO2-Gadget/ So, you can just stick it in USB charger anywhere and either use visuals or a mobile app that will show the number or import data for a chart. All for $60 from official Sensirion dealer like digikey. I don't mean to sound like an Ad, but it's the best sensor as far as I know, for least cost and nothing to solder (perhaps a negative for some :) No affiliation.
- rogers18445 4y ago
  This is indeed the absolute best value co2 consumer 24/7 monitor you can buy right now. You don't have control over calibration however, it's set to auto. So you need to expose it to outside air every 7 days or it will drift. The good news that a drift should be automatically fixed in just a few minutes after you take it outside. If you live in a high co2 area, the ppm values will not be accurate. But relative measurements will be. And you can just add the difference if you know it to any number you see.
FullKirby 4y ago
I signed up to their newsletter and instantly got a mail saying "Dear John, we have shipped your DIY kit... " with a very shady link to "track my package". What just happened here ??
- ahaucnx 4y ago
  Thanks for pointing this out. It seems we linked it to the wrong form (we have one internal one when we actually ship the kits)! Will fix this immediately.
miniwark 4y ago
There is another Open Source alternative by FabLab Barcelona. The SmartCitizen Kit: https://smartcitizen.me/ https://smartcitizen.me/ https://www.seeedstudio.com/Smart-Citizen-Starter-Kit-p-2865.html https://www.seeedstudio.com/Smart-Citizen-Starter-Kit-p-2865... It is mainly for outdoor pollution (including light & noise), but it also include indoor gaz sensors for Co2 and VOC.
Khaine 4y ago
This looks great, does it also measure VOCs? Aren't VOCs one of the main things households should be worried about?
xtiansimon 4y ago
What’s the application of this project? Education? Or verifying your high-rise apartment has good air quality?

557 points by ahaucnx 4y ago

This is an updated version of our DIY air quality monitor that now includes a configuration button and some other PCB improvements around the I2C bus. It has also pin breakouts so you can easily add additional sensors if required. Hardware and software are both open source and can easily be adjusted.

smcleod 4y ago
Nice! Great work making it open source!
Youden 4y ago
Was the decision to use pin headers instead of SMD components a conscious choice? For the particulate sensors it's unavoidable but you can use Sensirion's SCD4X series for CO2, just about any VOC chip you want, and an ESP32 module instead of dev board. It should be substantially cheaper overall since the components can be ordered in bulk and the only assembly needed would be the particulate sensor. I've been meaning to get around to it myself but I still haven't settled on how to power it. I'm really tempted to try stuffing it full of giant batteries so that it can run for at least around a year without a cable.
- ahaucnx 4y ago
  Most people find it easier to solder through holes than SMD. We use SMD in our commercial product. We are testing the SCD4x and like it so far. It might be a future option.
  - Youden 4y ago
    I guess what I'm asking is does it need to be hand-solderable? With places like JLCPCB offering cheap SMD assembly, SMD boards are still accessible to hobbyists.
    - mardifoufs 4y ago
      I though JLPCB only assembled components that are available in their catalogue. If they don't have the part you need, you'll have to hand assemble it. These are pretty niche components, with odd footprints and size so I'd be surprised if assembly was available.
      - Youden 4y ago
        You can have them order parts that are available at Mouser, Digikey and the other parts vendors. They have the SCD41 [0], SGP41 [1] and a variety of ESP32 modules (e.g. [2]) in their catalogue. The preorder prices can be a bit out of whack but they'll correct them when they actually buy the part. [0]: https://jlcpcb.com/partdetail/Sensirion-SCD41_DR2/C3659294 https://jlcpcb.com/partdetail/Sensirion-SCD41_DR2/C3659294 [1]: https://jlcpcb.com/partdetail/Sensirion-SGP41_DR4/C3659325 https://jlcpcb.com/partdetail/Sensirion-SGP41_DR4/C3659325 [2]: https://jlcpcb.com/partdetail/EspressifSystems-ESP32_S2_MINI_1N4/C2847294 https://jlcpcb.com/partdetail/EspressifSystems-ESP32_S2_MINI...
- comboy 4y ago
  If you want continuous measurement, battery is pretty much not an option, PM2.5 will use a small fan, so even at 30mA it's 30 * 24 * 365 so for a year you need 262,800mAh battery, it's a different voltage but to put it in context your laptop is likely under 10,000mAh. If you only need to take measurements say every 30mins then sure, but then either you worry about sending it somewhere and receiving it or you need to use additional battery power for displaying it.
aikinai 4y ago
Is there any way to checkout without PayPal? I was mysteriously banned a few years ago with no details and no recourse. And I don’t see an option to just pass through a credit card without logging in. Edit: Never mind! I found out tapping the credit card logo worked to do a pass through payment without logging into PayPal. Purchased! And thanks for supporting international shipping too!
- ahaucnx 4y ago
  I think you should be able to just pay with credit card. If you have problems please contact us through the support form.

deleted 4y ago

[deleted]

edge17 4y ago

Just out of curiousity, what are the equivalent commercial products in this space?

ahaucnx 4y ago
We also offer a fully certified commercial product (AirGradient ONE) focusing on B2B (Offices, Schools). Then you have monitors from other companies e.g. Awair, AirThings, Kaiterra, Air Visual etc measuring similar air quality parameters. We try to set us apart by promoting open data standards, clear data ownership, long lasting products that are easy to repair and maintain. More details on our main website [1]. [1] https://www.airgradient.com/ https://www.airgradient.com/
wallflower 4y ago
The IQAir is very nice. There is also the Purple Air monitor. https://www.iqair.com/us/air-quality-monitors https://www.iqair.com/us/air-quality-monitors https://www.purpleair.com https://www.purpleair.com
- erinnh 4y ago
  Totally not a judgement about the quality of it, but it amazes me how the IQAir is only supported via Cloud. Even for this really local information I need to contact some Cloud to be able to get the information into my smart home. This stuff annoys me a lot.
  - wodenokoto 4y ago
    I believe this is to support their pollution maps and pollution forecasts. Which makes the high price of the product odd to me.
  - ahaucnx 4y ago
    Yes unfortuntately we see a clear trend among other companies towards walled gardens, closed data and forcing people into subscriptions. We at AirGradient do not support this development and made very clear statements on our website.

Tempest1981 4y ago

I have a handheld $65 TVOC meter, but it's tricky to get repeatable measurements. It needs 5-10 minutes to warm up, but then the reading jump around almost 2x. It has 4 digits of resolution, but 1 digit of accuracy? Regardless, indoor TVOC levels increase significantly over 2-3 days. Then opening the windows brings them back down. Not sure if that's normal. (TVOC = Total volatile organic compounds) Any recommendations for quality sensors?

parker_mountain 4y ago
FWIW, TVOCs can collect together and move around in "waves", your indoor air is not just one big evenly distributed "soup". The sensors also have lots of factors that affect them, such as humidity - you can usually find more info in the docs for the sensor part. A better approach would be to sample consistently and use that to build a graph showing TVOC ppm over time.
ahaucnx 4y ago
Compared to CO2 and PM measurements, TVOCs are the most difficult to measure because they encompass a wide range of chemicals that trigger the sensor. Some are very harmful, e.g. aggressive paint and others (hopefully) harmless like sunscreen. Both trigger the sensor. Additionally the sensors are only showing you correct absolute levels in lab conditions, e.g. using ethanol at a specific temperature and humidity. So in real environments, the absolute values are pretty useless. We now use a newer generation of TVOC senor e.g. the SGP41 that is more index based and eliminates the issue of the absolute values. We also observe that temperature and humidity can influence the TVOC measurements. All in all, TVOC is good to detect spikes and check what is causing these, e.g. use of aggressive cleaning chemicals. However the absolute levels in e.g. ppb should better be ignored. Yes, it is normal that fresh air flushes out chemicals and you can see this improvement. We do like the SGP4x series from Sensirion for TVOC sensors.
- drakenot 4y ago
  Are they accurate enough for me to ensure I’m keeping VOC levels down while 3D printing different materials?

kayson 4y ago

Wish I had seen this before I bought all the constituent parts on sparkfun! Though I do have some concerns about the accuracy of the PM2.5 sensor (mainly because the data sheet isn't exceptionally clear).I ended up getting the Sensirion equivalent over this one even though its quite pricey. Every all-in-one air quality monitor I've seen except one omit some fairly important metrics - NO2 and hydrogen sulfides. I'm guessing it's because the sensors are extremely expensive (I got quotes for $90+/ea from one vendor). I ended up finding a startup, SPEC Sensors, that has much cheaper screen-printed sensors, and if their data sheets are to be believed, they're more than sufficient.

ahaucnx 4y ago
We have made very good experience with the Plantower PMS5003 PM sensor and thousands of them went through our test chamber. The plantower has also shown one of the best accuracies for low-cost sensors compared to reference stations in various studies. I agree that the data sheets from Plantower are not great. Unfortuntately this is often the case from Chinese manufacturers.
- comboy 4y ago
  I second Plantower (I've only used a few PMS7003), it allows you to build a really high quality sensor while being really a beginner project using some arduino and LCD. Note that this is only for particulates in the air. Btw, why thousands? And any reasons for not using CCS811 for TVOC and HDC1080 for temp while you're at it? Sounds like you have tons of experience and it's not easy to find reviews which properly test these.
  - ahaucnx 4y ago
    No specific reasons other than that we are pretty happy with the quality from Sensirion and thus like to use their sensors.
- kayson 4y ago
  That's good to know! Have you published your testing results anywhere?

jph 4y ago

This is super-useful. The TVOC / NOx module is especially compelling. Can I purchase it pre-soldered? I do see your commercial offering (AirGradient ONE) and I'd like to buy that for my office. How does a typical consumer purchase one online?

upon_drumhead 4y ago
They have pre-soldered kits in their store, which took me a hot minute to actually find. https://www.airgradient.com/open-airgradient/shop/ https://www.airgradient.com/open-airgradient/shop/
- ahaucnx 4y ago
  The presoldered kit also comes already pre-flashed and you can literally build it in 5-10 minutes. Just need to plug in the sensors, one cable and screw it together.

pigtailgirl 4y ago

-- live in seoul - air quality is sometimes "unbreathable" - using AirIQ api for smart home alert - https://www.iqair.com/us/air-pollution-data-api https://www.iqair.com/us/air-pollution-data-api --

maweki 4y ago

Is it common for the HN audience to be able to fabricate their own PCBs? I believe none of my local hacker spaces have fabrication facilities. Whenever I see that, it means having to pay somebody quite a bit instead of do it yourself.

Kuinox 4y ago
I built one. But without PCB. I just used wires and soldered it.
idiotsecant 4y ago
You can make your own PCBs quite easily with cheap chemicals, a laser printer, and some tubs to agitate the mixture. It's a bad idea though, when you can design them and get them made online incredibly cheaply.
aidenn0 4y ago
I haven't had any made in a while but last time I got 2 index-card sized PCBs with silk-screen and solder mask for under $40 after shipping.
dgacmu 4y ago
There are some home-brewable ways for single layer boards, particularly one sided -- you can do the old school copper board + mask + etch with something like ferric chloride. It's pretty easy but you do want to be careful as the chemicals are a bit nasty. Newer school is to print the mask and transfer using a laminator. You can also physically etch with a milling machine. It's a bit more expensive but low startup cost if you already have a small cnc mill. You probably have access to one at a maker space. That's most likely the easiest way to go.
jazzyjackson 4y ago
I guess I wouldn't say common - but hackerspaces and especially fablabs will often have a Roland CNC machine capable of carving PCBs out of copper-coated-fiberglass - but once you go through all that (paying for a couple broken 1/64" routing bits as you learn to use the machine...) it starts to make sense to pay $5 per square inch at oshpark

RobotToaster 4y ago

It isn't open source as it's under a NC licence, which restricts the field of endeavour. https://www.oshwa.org/faq/#non-commercial https://www.oshwa.org/faq/#non-commercial https://opensource.org/osd https://opensource.org/osd

simondotau 4y ago
No matter how much they wish it were otherwise, OSI doesn't get to dictate what "open source" means. It's not their trademark. The term existed before they did. And equally as importantly, the words open and source existed before they did. The source for AirGradient is not closed. It is open.
- RobotToaster 4y ago
  Looking again there aren't even any source files available for the PCB at all, only gerber files, which are purely manufacturing files.

patja 4y ago

A project I did to make CO2 monitors with a Sensiron SCD41 sensor and Adafruit MagTag e-ink module: https://www.printables.com/model/121265-salud-co2-monitor https://www.printables.com/model/121265-salud-co2-monitor

crazygringo 4y ago

This is tangential, but is anyone aware of a live outdoor CO2 levels map? I've never been able to find one anywhere. Because outdoor levels seem to vary significantly in a kind of 400-600 range, and it's impossible to calibrate a sensor outside without a reference point. On a windy winter day you can probably assume it's close to the global ~414, but on a muggy still summer day my sensors usually read significantly higher when holding them outdoors.

namibj 4y ago
You can use a chemical CO2 scrubber (e.g., bubbling air through a saturated solution of calcium hydroxide) to get a rather stable/repeatable sub-ambient reference to calibrate the sensor with. An aquarium bubbler , or rather two, should be easy to plumb to a CO2 sensor. Just skip the water bath for one of them. The calcium hydroxide is sold as "hydrated lime" and needs to just be stored isolated from CO2, and is mildly basic, so will slowly corrode your fingers (wash after touching, don't get any in your eyes). Shouldn't even need gloves for this usecase, where one occasionally swaps the water and sediment for fresh stuff. Btw, the waste, after soaking CO2, is just harmless limestone. Sprinkle around somewhat to make it a thin layer to ensure it all converts soon.
keenanj 4y ago
This is a plug for my non-profit building an open-source version of exactly that: ribbitnetwork.org. Our society deserves to have a publicly available map of outdoor emissions. There are lots of hard science and data analysis questions to solve in order to get there with reliable and cheap sensors, but I think it’s a journey worth going on. We’re on discord and GitHub if anyone wants to come build with us.
- crazygringo 4y ago
  Thank you! That's exactly the kind of thing I was looking for. I've been utterly baffled by how atmospheric CO2 is one of the very top issues of our time, and yet... I can get live temperature, humidity, and things like PM2.5, PM10, NO2, O3, etc... but not CO2. Since you're in this area, do you have any insight as to why? There are thousands of official air quality monitors used all over the world for calculating AQI and similar. Why did they skip CO2? Is there something inherently difficult or inaccurate about measuring it, is its short-term variation simply seen as irrelevant to health and not worth studying, or is there a political fear that live monitoring might somehow become ammunition for climate change deniers, along the lines of every winter blizzard leading to some people taunting "where's your global warming now?" The US government measures CO2 at the Mauna Loa Observatory in Hawaii... and seemingly nowhere else?

arriu 4y ago

How does this compare to something like the Aranet4 module?

ahaucnx 4y ago
It should give very similar results. As far as I know the Aranet also uses a CO2 Sensor from Senseair.
- thadk 4y ago
  It appears to be this $60 Senseair Sunrise however: https://sensormaestros.com/products/sensor/gas/co2/senseair-sunrise/ https://sensormaestros.com/products/sensor/gas/co2/senseair-... https://senseair.com/news/customer-cases/aranet4-senseair-sunrise-inside/ https://senseair.com/news/customer-cases/aranet4-senseair-su...

aedocw 4y ago

For folks who want to do something similar (no CO2 measure, and possibly less accurate) for far less per sensor, you can easily connect an ESP8266 ($5) to an IKEA VINDRIKTNING ($16) air quality sensor[1]. Stick a AM2302 ($7) on the outside and you get PM2.5, temperature and humidity for about $30. [1]: https://style.oversubstance.net/2021/08/diy-use-an-ikea-vindriktning-air-quality-sensor-in-home-assistant-with-esphome/ https://style.oversubstance.net/2021/08/diy-use-an-ikea-vind...

M3L0NM4N 4y ago
I will note though, CO2 measure indoors can be very valuable. Higher levels of CO2 result in less brain function, as shown by this Tom Scott video: https://youtu.be/1Nh_vxpycEA https://youtu.be/1Nh_vxpycEA
- reeckoh 4y ago
  They can also be a canary for other issues, like mold accumulation.
PaulBGD_ 4y ago
I have both a modded VINDRIKTNING and the airgradient, imo the airgradient is worth it if you want everything in one package. More accurate than the ikea, a nice screen/case, and you don’t have to strap a humidity sensor to the outside. Plus CO2 is great, more people need CO2 detectors.
deleted 4y ago
[deleted]
jve 4y ago
Did just that by following that particular tutorial. Didn't expect accuracy, just following how air quality changes when baking, turning on humidifier, etc. However now my VINDRIKTNING shows red with MAX reading all the time - I suppose not to be placed in the kitchen - some sticky oil grease landed on the sensor.

pfyy 4y ago

We made a small co2 sensor based on the sensirion scd30 and m5 stack. If you want a portable sensor with battery and display, you might be interested. Source code is on https://github.com/smoca-ag/m5stack_co2_sensor https://github.com/smoca-ag/m5stack_co2_sensor

pppone 4y ago

I would recommend checking out the AQ-SPEC program [1]. They do quite comprehensive tests on low-cost air quality sensors. My side project with a few friends [2] chose to use the Sensirion SPS30 [3] for our portable PM2.5 monitor. As mentioned by others, it's a bit more expensive than the PMS5003 used by AirGradient, but we preferred its documentation, company reputation, and form factor at the time of choosing (2019). The PMS5003 is perfectly capable, and has demonstrated good success with many projects/companies using the sensor (e.g. PurpleAir). However, a quick search suggests there are some issues with a recent batch of these sensors [4]. [1]: https://www.aqmd.gov/aq-spec/sensors https://www.aqmd.gov/aq-spec/sensors [2]: https://www.open-seneca.org/ https://www.open-seneca.org/ [3]: https://sensirion.com/products/catalog/SPS30/ https://sensirion.com/products/catalog/SPS30/ [4]: https://community.purpleair.com/t/new-version-of-plantower-pms5003/288 https://community.purpleair.com/t/new-version-of-plantower-p...

newman314 4y ago
Your site does not appear to have pricing for your kit based on brief browsing.
- chubbnix 4y ago
  They are about $50 from my search which is about 5x more than the plantower pm2.5 sensors. There is a big difference in documentation and that issue with the new MCU on the plantower units is concerning since they all have the same markings and housing when purchased.
  - pppone 4y ago
    At volume, the SPS30 gets down to ~$30 a piece. Their newest sensors (SEN5X) offer similar specs, and are about $25 per single unit, or $15 a piece at volume for the cheapest variant. The more expensive variant include integrated T/RH monitoring, which is very handy for humidity corrections for this type of PM2.5 sensing.
- pppone 4y ago
  Sadly not yet. Since this is more of a voluntary commitment amongst my friends and I (we're in the process of finishing our PhDs), we lack the human-power to take the product to market at the moment.

dragontamer 4y ago

Each time I see these, I feel a bit weird because they all rely upon a specific sensor, and the software / electronics is barely above beginner level. A PM2.5 sensor is based off of infrared LEDs and photodiodes. CO2 however is harder for me to understand. Does anyone know how that works? Temperature is easy: just a calibrated thermistor. Humidity: I dunno and am also curious. -------- It's be a lot more comfortable for me to call this open source if the sensors actually gave design control to the engineer, more so than just assembly.

breput 4y ago
The Senseair S8 CO₂ sensor[0] used in this project also uses an infrared LED and works on the principal that CO₂ absorbs certain frequencies of light. So if you know the brightness of the LED and the volume of air between it and the sensor, you can calculate the amount of CO₂ by comparing the expected vs. received light intensity. [0] https://rmtplusstoragesenseair.blob.core.windows.net/docs/publicerat/PSP126.pdf https://rmtplusstoragesenseair.blob.core.windows.net/docs/pu...
- dragontamer 4y ago
  Good to know. So methinks that a CO2 sensor would have to be based off of multiple LEDs + Photodiodes, to measure the absorbed light at _different_ frequencies. (LEDs and Photodiodes typically are only active at one frequency: such as 900nm or 700nm). If "all" frequencies are deflected, its PM2.5 (some particle got in the way of the measurement). If "some" frequencies are deflected, then its CO2. ---------- The question after that comes down to calibration and test data. Is there an easy way to create CO2 density and/or PM2.5 particles of a certain density? --------- There's a big difference. 1. Photodiodes and LEDs are extremely common parts manufactured by a wide variety of companies around the world. By tying yourself to Photodiodes/LEDs, you are less tied to any particular company. 2. Photodiodes and LEDs are well under 10-cents each. Though some more carefully calibrated ones / specialty ones may reach as high as $1 to $2.
  - breput 4y ago
    > (LEDs and Photodiodes typically are only active at one frequency: such as 900nm or 700nm). That's not entirely correct. The spec sheet for the LED will give an intensity vs. wavelength chart, which depending on the LED can be 10s to 100s of nanometers wide. As long as the source LED has a sufficiently bright output in one of the CO₂ absorption bands, it doesn't have to be exactly tuned like a laser. NDIR is the technology used in most consumer-grade CO₂ sensors: https://en.wikipedia.org/wiki/Nondispersive_infrared_sensor https://en.wikipedia.org/wiki/Nondispersive_infrared_sensor

1270018080 4y ago

Does anyone know of air quality monitors that check for NO2 as well as CO2?

slawwwc 4y ago
Air-Q does both. Looks interested, but I don't know much about the quality of their products. https://en.air-q.com/produktvarianten https://en.air-q.com/produktvarianten

deleted 4y ago

[deleted]

pbronez 4y ago

Anyone know how hard it would be to convert this from USB-C power & wifi connectivity to PoE for power + data? TI has PoE chips for around $4, but I don’t know enough about electrical engineering to figure out how to swap that into this design. https://www.ti.com/product/TPS23861 https://www.ti.com/product/TPS23861

pbronez 4y ago
Looks like you can get a PoE to USB-C adapter for $35: Revotech PoE to Type-C Adapter Converter, Convert POE to Output 5V/2.4A USB C with Ethernet, IEEE802.3af with 10/100Mbps , Wired Broadband and PD Charging for Smart Phone/Tablet, Plug and Play (P2C5V) https://a.co/d/7320MNa https://a.co/d/7320MNa Wonder how complex it is to access the network this way. If you have to modify the USB implementation you may as well skip the adapter and add an RJ45 + internal PoE chip…

NikolaNovak 4y ago

Open source diy is wonderful. But is there a reliable trustworthy monitor that can just... Be bought? A box that will reliably tell me what's the carbon dioxide carbon monoxide dust allergens volatile compounds? Am I possibly being greedy and I need several konitors (I wouldn't have an issue with that)? Every review I check for any consumer accessible device seems to indicate they're inaccurate, miscalibrated, or downright deceptive :-(

ahaucnx 4y ago
PM, CO2, temperature and humidity can be fairly accurately measured with consumer monitors provided they use good sensors. You can check if the monitor is RESET AIR certified which is an independent and 3rd party test against reference devices. https://www.reset.build/directory/monitors/air https://www.reset.build/directory/monitors/air
Forge36 4y ago
I spent $30 on one and $20 on another. They're "close enough" and I could connect them to home assistant. The reviews suggests the CO2 is off by 100 ppm. I've only seen VOC measurable when it's in my garage. It depends on your purpose.
tomaskafka 4y ago
Anything under $60 doesn't have a 'real' CO2 sensor. One of the good budget ones is Cleargrass Air Monitor.
- s0rce 4y ago
  You can diy for under 60 with a photoacoustic SCD41.
karmelapple 4y ago
The Aranet has worked well for me, and I think is calibrated well and works smoothly. It’s not the cheapest though, but I haven’t recharged it in over a year… almost two years now! https://a.co/d/9o1Qvzb https://a.co/d/9o1Qvzb

sc00ty 4y ago

I ordered two DIY pro kits (with the TVOC sensors) earlier this month and went to start working on them yesterday. After flashing the firmware, neither one would create a hotspot for me to connect to. Looking at them and doing some googling, i found they include knock-off Wemos D1 minis (labeled "mimi"). It looks like they're aware there are Wi-Fi issues, but the chips are still being used [0][1]. I sent in an email yesterday but I'm not expecting a response until at least tomorrow. [0]: https://www.airgradient.com/open-airgradient/blog/d1-mimi/ https://www.airgradient.com/open-airgradient/blog/d1-mimi/ [1]: https://forum.airgradient.com/t/issues-with-new-dyi-pro-presoldered-kit/414/22 https://forum.airgradient.com/t/issues-with-new-dyi-pro-pres...

ahaucnx 4y ago
Customer support will be in office tomorrow and we are sending a free replacement to all customers that have been impacted by a non working D1. The "Mimi" version should not have the problem and we found it to be very stable and it is currently our default version. More information here: https://www.airgradient.com/open-airgradient/blog/d1-mimi/ https://www.airgradient.com/open-airgradient/blog/d1-mimi/

pax 4y ago

Can AirGradient be made to contribute to https://sensor.community/ https://sensor.community/ or https://openaq.org https://openaq.org data streams? Or anything similar?

ahaucnx 4y ago
Yes very much. We are in touch with OpenAQ on this matter.

mastax 4y ago

I bought one of the DIY Pro kits and put it together. I liked it overall. I think the kit is a good value, it's convenient to get everything all together, and the injection molded case is nice. The included software and cloud dashboard are convenient and functional. There are some less good parts, though: - The instructions aren't great, but I can't remember what I had trouble with specifically. - The included screws for the case are tiny, soft, and aren't self tapping. I never got them in all the way and gave up on them after the first disassembly. The USB power cable sort-of holds the clamshell together without them. - I had issues with the reliability of the connection to the I2C sensors, especially after adding the SGP30. Reducing the speed to 100kHz helped somewhat but made the display update slowly. I never got the SHT3x temperature sensor to work reliably in the bottom corner position, so I moved it to the open top spot. I did try out various levels of I2C pull-up and removed redundant pull-ups from the modules that came with them installed. I think part of the problem is the loose fit of the included pin headers, soldering the sensors directly may help. - The temperature sensor always reads high by about 5-10 degrees F, even when installed in the recommended far corner position. I tried mounting the airgradient vertically to try to induce a draft to clear out the generated heat but that didn't help. I could try to calibrate it but I doubt it's a simple offset. - The dashboard is basic, had some annoying bugs, and they want you to pay for it. I can't remember specifically what I disliked because I replaced the firmware with EspHome long ago and set up a grafana dashboard to monitor it.

ahaucnx 4y ago
Thank you for your feedback. With the new version (3.7) that is also now sold as the updated kit we have addressed most of these issues. - we now supply stainless steel torx screws including screw driver - we have now the SGP41 AirGradient module in our shop that has no pull up resistors and works very stable - we redesigned the i2c circuit which now runs completely on 3.3v - so far we never charged a DIYer for our dashboard but might do so at a reasonable price in future if our server costs rise. We continue fixing issues (software and hardware) that come up in our forum and are dedicated to ensure we deliver a high quality kit.
- runjake 4y ago

edge17 4y ago

If I live next to a construction site, would something like this provide some guidance in terms if whether I should be doing more to clean up the air in my home?

ahaucnx 4y ago
The PM sensor will easily pick up the dust from the construction site and you will probably notice changes in wind direction as well.
harrydehal 4y ago
I run an indoor sensor from a different company and it definitely allows me to measure whenever the neighbors are doing yardwork, or there's a fire down the street, etc. My sensor is indoor, but I am curious about picking up an outdoor sensor to see if I can find any long-term correlation between a train passing and increase in emissions.

unclekev 4y ago

Anyone here using/found a decent Air Quality sensors that is plug and play with Home Assistant?

sunsetMurk 4y ago
I use a 'LEVOIT air purifier'[1], and it has a PM2.5 sensor that works w/ Home Assistant out of the box through the VeSync integration [2]. 1- https://smile.amazon.com/gp/product/B08L73QL1V https://smile.amazon.com/gp/product/B08L73QL1V 2- https://www.home-assistant.io/integrations/vesync/ https://www.home-assistant.io/integrations/vesync/
davidrhunt 4y ago
I struggled with the same search and ended up getting the AirGradient DIY Pro Kit Pre-Soldered. Not quite plug and play but the steps to get it up and running are fairly straightforward. Just plug parts in, drop some firmware on, and go. Curious what other suggestions are out there because I would still like something simpler! https://www.airgradient.com/open-airgradient/shop/#!/DIY-Pro-Kit-Pre-Soldered/p/476627519/category=0 https://www.airgradient.com/open-airgradient/shop/#!/DIY-Pro...

sytelus 4y ago

On a side note, Amazon's one of the least known great product is smart air quality monitor for under $100: https://www.amazon.com/Introducing-Amazon-Smart-Quality-Monitor/dp/B08W8KS8D3/ https://www.amazon.com/Introducing-Amazon-Smart-Quality-Moni...

ycombinatornews 4y ago
Doesn’t measure CO2. Just CO

hrez 4y ago

If you're like me and only looking for CO2 monitor, here is a short story. I was researching all the sensors and kits and was narrowing down on AirGradient actually. Per my research the best last gen CO2 sensors are from swiss Sensirion SCD4x series. So I started looking how to build something on it etc. While poking around, by pure chance I saw that Sensirion makes SCD4x-CO2-Gadget which is SCD41 sensor with LED indicator and BLE and powered by USB the size of flash drive. https://sensirion.com/products/catalog/SCD4x-CO2-Gadget/ https://sensirion.com/products/catalog/SCD4x-CO2-Gadget/ So, you can just stick it in USB charger anywhere and either use visuals or a mobile app that will show the number or import data for a chart. All for $60 from official Sensirion dealer like digikey. I don't mean to sound like an Ad, but it's the best sensor as far as I know, for least cost and nothing to solder (perhaps a negative for some :) No affiliation.

rogers18445 4y ago
This is indeed the absolute best value co2 consumer 24/7 monitor you can buy right now. You don't have control over calibration however, it's set to auto. So you need to expose it to outside air every 7 days or it will drift. The good news that a drift should be automatically fixed in just a few minutes after you take it outside. If you live in a high co2 area, the ppm values will not be accurate. But relative measurements will be. And you can just add the difference if you know it to any number you see.

FullKirby 4y ago

I signed up to their newsletter and instantly got a mail saying "Dear John, we have shipped your DIY kit... " with a very shady link to "track my package". What just happened here ??

ahaucnx 4y ago
Thanks for pointing this out. It seems we linked it to the wrong form (we have one internal one when we actually ship the kits)! Will fix this immediately.

miniwark 4y ago

There is another Open Source alternative by FabLab Barcelona. The SmartCitizen Kit: https://smartcitizen.me/ https://smartcitizen.me/ https://www.seeedstudio.com/Smart-Citizen-Starter-Kit-p-2865.html https://www.seeedstudio.com/Smart-Citizen-Starter-Kit-p-2865... It is mainly for outdoor pollution (including light & noise), but it also include indoor gaz sensors for Co2 and VOC.

Khaine 4y ago

This looks great, does it also measure VOCs? Aren't VOCs one of the main things households should be worried about?

xtiansimon 4y ago

What’s the application of this project? Education? Or verifying your high-rise apartment has good air quality?