[HN Gopher] Infineon's CO2 Sensor Monitors Indoor Air Quality
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Infineon's CO2 Sensor Monitors Indoor Air Quality
Author : WaitWaitWha
Score : 42 points
Date : 2024-09-21 19:08 UTC (3 hours ago)
(HTM) web link (www.allaboutcircuits.com)
(TXT) w3m dump (www.allaboutcircuits.com)
| vardump wrote:
| Finally an actually working (cheap?) CO2 sensor?
|
| So many of those actually measure humidity, temp and VOCs and try
| to derive some sort of CO2 reading out of those.
| IgorPartola wrote:
| This was my thought exactly. I used sensors that were about
| $25/each in the past and those worked well but this would be
| seemingly way easier to integrate and get ahold of.
| vardump wrote:
| $25 for a CO2 sensor component that actually works is not bad
| at all.
| tobi1449 wrote:
| Sensirion SCD41 should be pretty good, right? You can get
| them for ~25 USD on aliexpress ...
| ale42 wrote:
| I'm not sure I would source non-Chinese electronic
| components from Aliexpress... (unless it's just to play
| with them, definitely not for a product): you might need
| to check their reliability and quality. Pretty sure that
| Sensirion themselves are not selling there, so they are
| probably either clones, fakes, recycled ones, or if you
| are lucky authentic ones that for some reason ended up
| there (but I can't imagine a way).
| fuzzy2 wrote:
| Sensirion has the SCD40, which appears to be based on the same
| principle. It's much cheaper than the SCD30.
| _blk wrote:
| Yes, SCD30 series are optical while SCD40 series are
| photoacoustic. STC series are thermal conductivity based. STC
| and SCD40 are smaller than SCD30 but less accurate if memory
| serves (check datasheet).
| rainburg wrote:
| The Senseair S88, which was released earlier this year, costs
| ~$22/piece, or ~$13/piece if you order more than 100.
| tzs wrote:
| It's not really "finally". They introduced a similar sensor,
| the PASCO2V01, a couple years ago. That one has been available
| on a breakout board with the necessary support hardware from
| SparkFun for over a year [1].
|
| Comparing the datasheets for the PASCO2V01 and the new
| PASCO2V15 the old one actually seems a little better as far as
| CO2 measuring performance goes. They are the same on most
| things, but the old one has slightly better accuracy.
|
| The new one is +-(50 ppm + 5%) between 400 ppm and 3000 ppm.
|
| The old one is +-(30 ppm + 3%) between 400 ppm and 5000 ppm.
|
| The big difference is this:
|
| > Infineon has recently introduced the PASCO2V15, a new 5 V
| sensor to improve air quality monitoring in building
| environments.
|
| Both of them require a dual voltage power supply. They both
| want 3.3 V for their digital components and a higher voltage
| for their IR emitter.
|
| For the older one that higher voltage is 12 V. For the newer it
| is 5 V.
|
| [1] https://www.sparkfun.com/products/22956
| fnordpiglet wrote:
| Iirc they were merged into esphome last year too.
| Animats wrote:
| True. The cheap ones are trying to guess CO2. Those are called
| "indoor air quality sensors".
|
| Small CO2 sensors have been available for years, for about $50.
| Compare [1].
|
| Life of this new device is only 10 years, which is short for
| HVAC systems. A hotel might have a thousand of these. Older
| devices say "15+" years.
|
| All these devices have a calibration problem. They drift. They
| try to correct by treating the lowest value they ever see as
| "normal" (that's about 400 ppm CO2 today, vs 300 PPM in 1950)
| and recalibrating. So they're not useful for observing a
| general increase in CO2. They're also not useful for
| greenhouses, where CO2 levels may drop below ambient CO2 due to
| photosynthesis. Manual recalibration is possible but requires
| feeding in pure nitrogen and a known nitrogen/CO2 mixture.[2]
|
| Devices which don't need that re-calibration exist.[3] They're
| more complicated. Also don't seem to be stocked by the usual
| distributors.
|
| [1]
| https://rmtplusstoragesenseair.blob.core.windows.net/docs/pu...
|
| [2] https://www.co2meter.com/blogs/news/7512282-co2-sensor-
| calib...
|
| [3] https://www.murata.com/en-
| us/products/sensor/co2/overview/te...
| nimish wrote:
| They've had a 12v version for a while, and it's quite nice
| despite the high voltage requirement. I made a little breakout
| with a boost converter. Sensirion has a slightly smaller sensor
| as well, SCD41 that I think works on similar principles.
|
| Neither are cheap, around $25-40 each in small quantities. The
| infineon one has a full blown microcontroller handling the
| operation of the sensors.
|
| To keep accuracy you would need to have a CO2 gas setup which
| isn't cheap either, but for indoor use I don't think it matters.
| shadowpho wrote:
| Have been using scd30/31/40. Great sensors. This one requires a
| bit more power but would be interesting to see price as it seems
| it actually measured CO2. (A lot of other sensors simulate it
| with measuring alcohols and assume people breathing which gives
| poor results)
| clumsysmurf wrote:
| I worked in a building 500 ft from a busy highway and when I
| cleaned my desk it always had black dust on it.
|
| Along these lines of air quality, can anyone recommend a
| similarly advanced PM2.5 / PM10 sensor under $100 / ea?
| trog wrote:
| I haven't gotten their PM sensor unit but have a CO2 sensor
| from CO2.click. About to pull the trigger on a PM sensor but
| just deciding which one. The founder there is active on a few
| places including Mastodon and I really like my CO2 sensor from
| them.
|
| Edit: sorry missed your price guidance. They are quite a bit
| more so probably not what you're after!
| christina97 wrote:
| Have been using a Plantower PMS5003 for a while with ESPhome
| and it's pretty good.
| dzhiurgis wrote:
| Would be nice if they packaged these up in laptops - fan is
| already there and always running.
| Genbox wrote:
| Datasheet can be found here:
| https://www.infineon.com/dgdl/Infineon-PASCO2V15-DataSheet-v...
| FL33TW00D wrote:
| I've been considering designing a wearable that monitors CO2 and
| PM2.5 continuously, but I'm unsure if people would wear it in
| conjunction with an Apple Watch or similar.
| crazygringo wrote:
| I'm not sure how accurate that would be on your wrist, because
| the proportion of recently exhaled air would be so much higher,
| since it's only a foot or two from your mouth.
|
| CO2 monitors often have little silent fans to draw in fresh air
| as well, for accuracy.
| christina97 wrote:
| I don't think it'd make a difference. I've got one on my desk
| in front of me and can't detect a difference with me at the
| desk vs not.
| triwats wrote:
| This is super interesting for me - but I'd love to put it on a
| bicycle (they are often locked up and stationary - for example)
| but move at faster speeds. Maybe this means they are only
| useful at tracking information when locked/stationary?
|
| I really like the idea of using cheap (?) devices in a sort of
| mesh to feed back telemetry data on pollution. Pollution is
| everyone's concern, so visualising that would be cool.
|
| Interested to hear if you had any more thoughts on this!
| OldGuyInTheClub wrote:
| Nice to see this miniaturization of photoacoustic spectroscopy -
| something I've done a bit of in the past. It is an
| underappreciated technique. Ordinarily one measures the
| difference in optical throughput with and without a sample. If it
| is a weak absorber, it is a difference between two large numbers.
| PAS is zero background. No absorption, no pressure wave, no
| signal. Any absorption stands out clearly against that zero
| background.
| babl-yc wrote:
| Seems similar to the SCD40 photoacoustic approach.
|
| I used that for an open-source CO2 monitor I designed:
|
| https://bitclock.io/
|
| https://github.com/goat-hill/bitclock
| JSDevOps wrote:
| https://aranet.com/en/home/products/aranet4-home?srsltid=Afm...
| elliottkember wrote:
| Like that, but cheaper and more accurate.
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