Actually, the reason CO2 sensors are used for air quality monitoring instead of oxygen sensors has nothing to do with cost, energy usage, size or how complicated they are (though they are costly). It's because we're not interested in oxygen levels, as it's very difficult to lower the oxygen levels to any appreciable level unless a room is sealed with a lot of people, but CO2 itself is toxic in high concentrations, and it can produce dizziness, feeling tired, and other related symptoms, starting from 1000-2000 ppm (that's only 0.1-0.2 %! At those levels oxygen concentration would, at most, fall from 21 % to 20.8-20.9 %, not near enough for any appreciable effect). Here's a link to a Tom Scott video about that if you want to learn more: kzfaq.info/get/bejne/Z7SYktmp1d_HdXU.html.
@AndreasSpiess4 жыл бұрын
I am not sure about the whole thing anymore. In submarines with atomic bombs on board and in the Space Station the CO2 level seems to be around 5000 ppm all year round. I hope, these guy do not loose their abilities to think... I would have been interested in the O2 level at the end of his test.
@AndersJackson4 жыл бұрын
@@AndreasSpiess that is why the have tests before sending people down or up. :-) Another thing. In Soda generator, like Soda Stream, there are CO2 gas tubes. So there you also will have access to pure CO2.
@subspace6663 жыл бұрын
@@AndreasSpiess not sure about subs if they use a hack to compensate like increasing o2 levels or playing with pressure , but for space your o2 expenditure is greatly decreased in low or no gravity situations ,so probably can tolerate much higher co2 concentrations kinda like sick people here with reduced lung capacity might not need supplemental o2 when not doing physical activities. if you use less oxygen your lungs have less gas exchanging to do.
@GRBtutorials3 жыл бұрын
@Issac Anakin Yes, the police and KZfaq mods are very interested in your hacking Instagram scam.
@MaximumEfficiency2 жыл бұрын
I can't find anyone measuring o2 in different areas: forest, city, dessert, sea, cave, basement, apartment etc. that data could be interesting, why is nobody measuring that?
@AriBenDavid4 жыл бұрын
CO2 levels can go up to 7000 ppm in submarines and space capsules. These levels are tolerable, but the CO2 level is an easily measured proxy for the usually accompanying high levels of VOCs and other air contaminants . We once measured CO2 levels in a crowded art studio. The air was stuffy and oppressive. Levels were 4500 ppm. The room needed more ventilation. I have also measured levels outside when many trees were photosynthesizing. They were just above 300. "Ah, fresh air!" They can get even lower during the day in a growing cornfield. And, your breath might be 40,000 ppm!
@AndreasSpiess4 жыл бұрын
Interesting information! I also read about the high levels of CO2 in submarines. This is why I thought, the oxygen level must be important in crowded rooms.
@MaximumEfficiency2 жыл бұрын
did you measure o2?
@AriBenDavid2 жыл бұрын
@@MaximumEfficiency Harder to measure but not usually considered an issue as CO2 is.
@LarryKapp14 жыл бұрын
yes just like you say - one of the new buildings where I worked had a CO2 sensor which was supposed to open up outside air dampers to bring in more air. But while the engineers had specified it and the controls company installed it - but they never calibrated it or made sure that it worked properly. So it did not really ever do anything useful. I was on maintenance but that was not my building and we were all just getting up to speed on how the new DDC HVAC systems were supposed to work and also too busy fixing the most blatant screw ups that the controls company left for us. No they never had anyone commission the buildings which did seem really stupid for multi- million dollar buildings. I wish I had seen your video many years ago so I could have fixed that CO2 sensor issue !
@AndreasSpiess4 жыл бұрын
From my normal job I know: "Not tested means not working" ;-)
@Sensirion4 жыл бұрын
Thank you very much Andreas Spiess for this great measuring CO2 tutorial and for evaluating our environmental sensors SGP30 and SCD30.
@AndreasSpiess4 жыл бұрын
Thank you!
@hypnagogio4 жыл бұрын
Just wanted to reach out and say thank you for the content you are producing. The quality is excellent. You are structured and follow a clear logic in your presentations. Great overall! Keep it up!
@AndreasSpiess4 жыл бұрын
Thank you for your nice words!
@daromee4 жыл бұрын
Incredible presentation ,as an Environmental Engineer who works with these types of sensors and many others I am highly impressed of your depth of knowledge in this field. Kudos !! you never cease to amaze me you have an incredible grasp of so many fields .
@AndreasSpiess4 жыл бұрын
I am old and had a lot of time to learn ;-)
@AJB2K34 жыл бұрын
Again, another useful video and again you have helped me unknowingly with an unconnected project. Please keep up the good work.
@AndreasSpiess4 жыл бұрын
Thank you. I will!
@ChriDDel4 жыл бұрын
The school of my son has a CO2 meter with colored LEDs in every classroom.
@AndreasSpiess4 жыл бұрын
This seams to be an exemplary school!
@erickcampos503 жыл бұрын
Very nice! Where are you from?
@ChriDDel3 жыл бұрын
@@erickcampos50 Northern Germany. It is indeed not normal for schools here.
@hey-zq1vq2 жыл бұрын
@@ChriDDel Warum gibt es sowas bei uns nicht. Macht mit Corona ja noch mehr Sinn
@forbiddenera Жыл бұрын
@@ChriDDel doubt it's normal anywhere but it is fkn awesome!
@MichalKottman4 жыл бұрын
Nice coincidence, jist yesterday I started trying out a VOC sensor to make a "fart detector", planned be used to identify when our cat uses the toilet.
@beware_the_moose4 жыл бұрын
solving life's problems, one cat fart detector at a time.
@thebeststooge4 жыл бұрын
LOL.
@shawnniedetzki75484 жыл бұрын
I had just thought about this the other day for my cats as well, to determine which one and when they are deciding to not use their litter box.
@chrislambe4004 жыл бұрын
Thanks dude, now getting cat food ads in the video.
@dd03564 жыл бұрын
maybe it will help decide better food for humans?
@uwezimmermann54274 жыл бұрын
As a German living in Sweden I have to point out that SENSEAIR is a Swedish company. I have recently been involved with them as being an opponent in a thesis defense which deals with the improvement of both their CO2 and CH4 sensors.
@uwezimmermann54274 жыл бұрын
I do not seem to find the online version of the thesis... www.miun.se/en/Research/research-centers/stc-researchcentre/news-from-stc-research-center-eng/News-archive/2019-10/bakhram-guynullin-presents-his-licentiate-thesis/
@AndreasSpiess4 жыл бұрын
Thank you for the correction. I got it from a German viewer and did not check further...
@tedenda4 жыл бұрын
Andreas Spiess I have been involved in a plug-in for ESP-Easy firmware for SenseAir S8 sensor. Look here: github.com/letscontrolit/ESPEasy/blob/mega/src/_P052_SenseAir.ino
@user-cu5fq9ys3u4 жыл бұрын
Thanks for yet another great video. I have been using the MH-Z19B in exactly this way, to alert when I need to ventilate the room. Has been working for over 2 years now without any problems. However I was not able to make it work on 3.3V, only on 5V. Second thing - i needed to turn off the correction (ABC) - otherwise the values would drift off considerably with time, especially if windows are rarely opened in winter. The SCD40 looks very interesting. Would like to try it out as well, I guess it should also have a reasonable power consumption to use it in battery powered device. Then you can even carry it with you everywhere))
@AndreasSpiess4 жыл бұрын
You are right. Vcc is 5V. only the logic levels are 3.3 volt.
@svrestless34254 жыл бұрын
Nice video. You are an inspiration. I just used senserion TVOC and senserion CO2 sensor a couple weeks ago. I actually used your node-red videos as reference. Thanks alot for that btw. Anyways what was shocking for me where the tvoc readings when I 3D printed. They where off the charts, and and for sure not healthy.
@andrewpaterson519216 күн бұрын
It is shocking to see the difference in background CO2 in 6 years from 2018 to 2024. NIWA Baring Head in NZ is 421.5ppm today and Mauna Loa Hawaii is 427.5ppm. So it is likely that the new 2024 calibration point should be around 430ppm for the Northern Hemisphere and 420ppm for the Southern Hemisphere. Your video is , still, extremely helpful. Far more than any other on KZfaq, even recently, related to these inexpensive IAQ sensors. My very cheap (
@AndreasSpiess16 күн бұрын
Interresting that the values are already so high! Thanks for the update. Concerning the eVOC sensors: As said, I was not very happy with them.
@joergherrmann38644 жыл бұрын
I did a lot research on Voc sensors. Voc (mox) sensor are heavily influenced by humidity amongst other factors. That's why your sgp30 shows that high value during the night. Even very low changes in humitdy counts for some 100ppm voc. I'm not aware of any single implementation that is able produce values usable over a period for days or weeks. Yes, they respond to changes very good but not on a absolute level. Co2 (mhz19b) must be the primary indicator.
@AndreasSpiess4 жыл бұрын
Good to know. I also trust the CO2 sensors more.
@_adamalfath4 жыл бұрын
As always, nice no BS explanation. I hope in the next video you also explain the best sensor/method to measure air quality on workshop environment. Like source from solder fume, glue gun, 3d filament, etc. Can't wait!!!
@AndreasSpiess4 жыл бұрын
The VOC sensors at least should show some of the "dangers". But I am no Chemist...
@thomascziesla37684 жыл бұрын
Nice to see that I‘m not alone to point out CO2 monitoring in schools! At the school of my kids I‘ve implemented a project making CO2 traffic light using MHZ19B sensors and RGB LED. After making some prototypes the teachers took over the idea and they made some enhancements as part of a junior academy project. I think I planted something...😀
@AndreasSpiess4 жыл бұрын
Very good! It is best when students learn with things relevant for their life.
@arhitektche4 жыл бұрын
Do the same video for fine particles sensors
@svrestless34254 жыл бұрын
Just as easy as for other inspection. Either I2c or uart. There is also a lib for that in arduino ide
@AndreasSpiess4 жыл бұрын
I cannot do this where I live. It would be very boring. The sensor would always show zero (i tried).
@davesemmelink89644 жыл бұрын
I have ordered a PMS5003 air particle sensor and will be trying this once it arrives. I originally wanted to get an SDS011, but I haven't found them locally. Does anyone know which is better? There is also one that does not use a fan, but I couldn't find it last time I looked - the fan will wear out eventually. Unlike Switzerland, South Africa has serious air quality issues in many places. We want to teach school kids about this. Many adults I know are completely unaware of this.
@grindel804 жыл бұрын
hahah i have to laught everytime is see the little hand :D (+1 for the cat)
@AndreasSpiess4 жыл бұрын
It is a good way to show small things...
@Snakke404 жыл бұрын
@ 17:00 "[ ...] without oxygen the fire stops. Problem solved without collateral damage." As long as there are no humans in the same room. Else there will be a lot of collateral damage!
@vincentnonnenmacher93524 жыл бұрын
No that’s fine, because a good IT dwarf will send other people (e.g interns) to overlook the most important stuff (read servers, because some cost oriented people didn’t allow you a decent video stream of your puppies) and will monitor its health (obviously I’m talking about servers one). If humans probes eventually returns, everything is fine, it’s means your monitoring is validated by a secondary data flow (just document it). If not a review of your backup plan could be an consideration.
@koma-k4 жыл бұрын
And that is why all such systems that I've seen use an inert mix of gases that are non-toxic (CO2 only would not be good). Some data centres use a reduced oxygen atmosphere (15-16%) which prevents fires from even starting, as the oxygen content is too low. Some people are more affected by this than others, getting more easily exhausted and getting a headache when working there, while others barely notice (luckily I'm in that last group).
@SlykeThePhoxenix4 жыл бұрын
I think there's an evacuate alarm that goes off. Gives people a few minutes to get out. I also think it's not just pure CO2, but a mix of stuff, so any occupants would still pass out, but probably not die. Smoke inhalation/fire is probably going to kill them before the CO2 does anyway, but I'm no expert.
@ramradhakrishnan93824 жыл бұрын
HaHa, Back in the day when I worked on large IBM Mainframes, there were Automatic Halon Fire extinguishing systems which would rob the fire of oxygen. Needless to say it would be disastrous if you hung around! Yet, there were posted signs asking the operators to unload all tape drives, label them, then store them carefully in the fireproof and exit the computer room swiftly if possible.(!)
@wilyartihoward20714 жыл бұрын
You just read my mind! I just built one of these! With the MH Z19B.
@AndreasSpiess4 жыл бұрын
Are you happy with it?
@Os.-4 жыл бұрын
I have to say I like your presentations. A handy video, like most of yours are - I'll have to check out the Raspberry Pi series again! Thanks for doing these :)
@AndreasSpiess4 жыл бұрын
You are welcome!
@jub88914 жыл бұрын
i have a sharp air purifier that triggers the fan whenever i fart. it also gets triggered by alcohol fumes, like in anti-bacterial hand wash. it must be almost 10 years old now but the sensor is still very sensitive to changes in the air
@SlykeThePhoxenix4 жыл бұрын
A fart controlled fan! My gf would love to get me one for Christmas!
@LawpickingLocksmith4 жыл бұрын
I have a 20 year old split air-conditioner made in Japan and still goes like new. Buy Chinese made and keep replacing.
@coffeecuppepsi4 жыл бұрын
one fart to turn fan on, two farts turns it off?
@foxabilo4 жыл бұрын
You are a genius sir, that is a fantastic idea!
@AndreasSpiess4 жыл бұрын
Thank you!
@Ed196014 жыл бұрын
I have been using the Winsen for some time already in a greenhouse. Very reliable
@AndreasSpiess4 жыл бұрын
Thank you for your feedback!
@AriBenDavid4 жыл бұрын
What levels do you get there?
@Ed196014 жыл бұрын
@@AriBenDavid high ones as I induce co2 in my greenhouse to promote growth, so it carries no relation to atmospheric co2 if that was yr interest
@DougHanchard4 жыл бұрын
This episode should be a high school homework assignment.
@AndreasSpiess4 жыл бұрын
Maybe some of my viewers are teachers?
@nashaut76354 жыл бұрын
@@AndreasSpiess I know one who is and I'll suggest him :)
@Snofperiment4 жыл бұрын
Yes am a biology teacher at high school in Netherlands. And I love iot. See my comment above. Would be fun to build!
@Leif_YT4 жыл бұрын
Perfect timing. I just hooked up my first MHZ19B 2-3 days ago. Sometimes i get massive co2 value drops that i can't really explain. Like in the middle of the night without opening a window or door. One drop could be the automatic 24h calibration, but the other ones confuse me a little bit. One problem could be that it's still on my breadboard powered by the 5V pin of a D1 Mini, another one could be that 2-3 days are just not enough time to be fully calibrated. But so far it does a much better job than the CCS811 eCO2 i tried a few months ago. Maybe those TVOC Sensors like the SGP30 / CCS811 could be useful for a hobby room with all kinds of gases / particles.
@AriBenDavid4 жыл бұрын
I see this, too. I think it is variations in wind levels and directions, affecting the amount of outside air infiltrating the house.
@AndreasSpiess4 жыл бұрын
I have now a ESP32 with different sensors reporting. I hope, that I will see a pattern after a few month. I disabled auto calibration to see what they really measure and only will enable it when I know that.
@Xgy332 жыл бұрын
You are a legend professor!
@AndreasSpiess2 жыл бұрын
:-)
@r1273m4 жыл бұрын
Bananas emit ethylene gas. This is why they can be picked before they are ripe and then ripened in stores that circulate the ethylene which helps the ripening process. My wife places unripe pears next to the bananas to help the pears to ripen. Bob
@AndreasSpiess4 жыл бұрын
The son of my brother worked in a company where they ripe the bananas for Switzerland's biggest retailer (just in time). I did not believe it first ;-)
@foxabilo4 жыл бұрын
After a long weekend of drinking, I have many toxic gasses in my apartment.
@AndreasSpiess4 жыл бұрын
:-))
@TDG26544 жыл бұрын
The reason lambda sensors are not used indoors, is because they need to be quite hot too work. Around 300 to 600°C hot. Inside the exhaust of an engine this is not too big an issue, but in open air it would take quite a bit of power
@AndreasSpiess4 жыл бұрын
That is what I also thought because it works in the exhaust path. But I did not know it is mandatory. Thanks.!
@tonysfun4 жыл бұрын
Very nice again! I need to make mine soon, since my hobby rooms are all in the basement! Thank you again Andreas!
@AndreasSpiess4 жыл бұрын
We "submariners" in the basements maybe are used to higher dosages. In a submarine the CO2 concentrations are at least 10 times higher than in fresh air!
@tonysfun4 жыл бұрын
@@AndreasSpiess I did not know! I learn something new every day from you Andreas! Thank you very much! PS: Can't remember if I asked you also about my kit to make Tesla Coil. It is on my youtube channel: kzfaq.info/sun/PLv52A7rm-UViZEOlzZfZOB9Gl8cjS3ze5 the very first, newest video. I don't like to hurt myself or someone else, but it would be nice to make this TC soon. So far no answers from anyone.
@AndreasSpiess4 жыл бұрын
You have just doubled your number of subscribers ;-)
@MichaRutkowskiEngineering4 жыл бұрын
Great material! It is a good thing to always seat in front row
@AndreasSpiess4 жыл бұрын
Thank you!
@marcos.17673 жыл бұрын
Great video. And more relevant than ever as right now in Germany we'll start to have a "venting" intiative at schools during Corona pandemic.
@AndreasSpiess3 жыл бұрын
That is why I chose the timing. I had the topic on my table for the whole summer, but it did not catch my attention...
@tomgeorge37264 жыл бұрын
Automotive O2 sensors will only work at high temperatures, not room temperature. Some O2 sensors have built in heaters or rely on the vehicle to heat the sensor as it warms up. The vehicle engine and ECU can run without the O2 sensor, this is called OPEN LOOP when cold. When the engine and O2 is heated, the ECU then runs using the O2 sensor reading, CLOSED LOOP operation.
@AndreasSpiess4 жыл бұрын
I see. I did not know heat was a prerequisite. Thanks!
@MaximumEfficiency2 жыл бұрын
do you have any data on o2 in different areas: forest, city, dessert, sea, cave, basement, apartment etc.?
@avatarteamultra4 жыл бұрын
Nice coincidence There was a "zukunftstag" at ETH Zurich two weeks ago. We have built CO2 measuring boxes with kids. At the end they could take them home and place them in their classroom now they know when to let some fresh air in.
@AndreasSpiess4 жыл бұрын
Good idea from my Alma Mater... Which sensor did you use?
@avatarteamultra4 жыл бұрын
@@AndreasSpiess a MQ135
@AndreasSpiess4 жыл бұрын
Not a good choice for CO2, I think. But maybe the price was important...
@neilw2O4 жыл бұрын
Andreas! Nicely documented and explained.
@AndreasSpiess4 жыл бұрын
Thank you!
@dimonmontana4 жыл бұрын
You absolutely forgot about the ccs811. It's really cool and chip sensor with low power mode.
@AndreasSpiess4 жыл бұрын
Looking at its datasheet it is very similar to the one I used. I would expect the same issues.
@viniciusnoyoutube4 жыл бұрын
Another fantastic project and video! Thanks!
@AndreasSpiess4 жыл бұрын
You are welcome!
@BerndFelsche4 жыл бұрын
CO2 levels in outdoor air vary considerably over the day and between seasons. They also vary substantially between locations, even at the same altitude. Using a global average is like using the average of telephone numbers to call somebody. CO2 gas presence is a sign of life... Essential for the carbon cycle that sustains our lives. When CO2 levels decline below about 180ppm, plant life struggles. You could hike up to the treeline on a nearby mountain and calibrate your sensor to a baseline of about 200ppm during daylight hours. CO2 levels can be higher at night due to decomposition of biomass and a slight increase in air pressure... But without sunlight, the higher CO2 is of no use to plants. Exhaled breath contains about 40000ppm ... sometimes higher. If your readings are substantially lower then it's likely that the sensor is wrong. P.S. drowsiness at University lectures was more closely correlated to the acoustic emissions at the front of the theatre than ambient CO2 levels 😀
@AndreasSpiess4 жыл бұрын
Do you know how much the CO2 level differs from place to place. I did not find such information. I assume it is only a few PPM
@BerndFelsche4 жыл бұрын
Nearby, well flushed locations are within about 5ppm. See e.g www.mdpi.com/2073-4433/9/10/367 Globally, variations are wider... IIRC 20ppm variation at sea level between the tropics and temperate regions of the Atlantic, at the same time of day. That was by measurements taken during the 1920's. Proper calibration is only by calibration gas mixtures.
@AndreasSpiess4 жыл бұрын
I also found info here: www.esrl.noaa.gov/gmd/ccgg/trends/monthly.html For our sensors these variations are below measuring errors.
@CarlOlovGustav4 жыл бұрын
True, but relying on the ABC algorithm started by Senseair in early 90ties tracks and keeps in sensor memory only the lowest such outdoor reading, which is very easy then to correlate to the atmospheric baseline. Temporary local emissions and peaks and other variance over the day/week are don't care. Seasonal variance (green plants in summer vs. autumn and winter bio decay) still apply if there's no added intelligence, but that's not a very big impact to atmospheric baseline and NDIR sensor accuracy. The true strength of ABC is however that any faulty drift offset over the lifetime (15+ years) is naturally delimited to the continuous effective sampling of the atmospheric baseline, so it never spirals out of control compared to dual-channel NDIR sensors that rely on internal reference signal ratios that is "assumed" pristine forever but typically only lasts a few years.
@MaximumEfficiency2 жыл бұрын
also higher CO2 levels help plants grow faster (and absorb more carbon as a building block)! btw do you have any data on o2 in different areas: forest, city, dessert, sea, cave, basement, apartment etc.?
@Olavotemrazaodenovo4 жыл бұрын
Congratulations from Brazil. Here is the guy with brazilian accent.
@AndreasSpiess4 жыл бұрын
Thank you!
@zyghom2 жыл бұрын
I deployed MHZ19B and it works like a charm with ESP32 It did not change my life but I am opening the window more often - bills for heating will go up during winter ;-) Btw after researching available sensors I am happy I decided to go for this one - it gives nice and stable readings - going to sleep with 400ppm and in the morning it is 1500 - hmm, now I understand why sometimes I wake up more tired than I went to sleep
@AndreasSpiess2 жыл бұрын
Indeed, 1500ppm is a lot. So maybe a little more money for heating is a good thing!
@zyghom2 жыл бұрын
@@AndreasSpiess I agree, however OSHA agencies provide "acceptable level < 5000 for long time work (8h or so)" - I believe it is way too high - I set up the alarm in my home assistant at 2000 ;-)
@Rouverius4 жыл бұрын
I think the major problem with lambda sensors is the high operating temperature required (300° to 600° C). I've been in pretty hot meeting rooms before but even this is a bit much.
@user-cu5fq9ys3u4 жыл бұрын
I think this is also because the exhaust oxygen varies a lot (0-20%), where as humans don't consume nearly as much and change is harder to detect
@Dimitriedmr4 жыл бұрын
As always Andreas does great videos.
@AndreasSpiess4 жыл бұрын
Thank you!
@pioupiou39354 жыл бұрын
Always very interesting video, thank you very much !
@AndreasSpiess4 жыл бұрын
You are welcome!
@electronic79794 жыл бұрын
Very good and helpful video 👍
@AndreasSpiess4 жыл бұрын
Thank you!
@thesimbon4 жыл бұрын
Please do a comparison with CO sensors too and possibly PM/dust sensors
@AndreasSpiess4 жыл бұрын
I am not sure if PM sensors are needed inside. I had one outside and it was boring. Too clean air :-)
@thesimbon4 жыл бұрын
@@AndreasSpiess because you don't live in the center of Milan 😅
@369ranch Жыл бұрын
I am back in school later in life and I agree that we need sensors in each classroom. I always thought there was a reason such as this that you get exhausted after 50 minutes in a class.
@AndreasSpiess Жыл бұрын
Maybe this is the reason, maybe it needs some time to get used to the school situation again ;-)
@brainfornothing4 жыл бұрын
Very interesting. Thanks for sharing !
@AndreasSpiess4 жыл бұрын
You are welcome!
@bryanst.martin71344 жыл бұрын
@17:21 your breath is lethal! ;-) This is a good reason for such a device. In my experience teachers can be extremely boring, and having a poor environment for your brain doesn't help.
@bryanst.martin71344 жыл бұрын
So if you perform CPR, are you committing attempted murder? How about we conjure up a CPR respirator that doesn't give CO2 to the victim?
@AndreasSpiess4 жыл бұрын
In many situations people use air several times (if you hyperventilate, for example). Oxigen is not used up by only one time breathing.
@AnotherMaker4 жыл бұрын
I'm glad you used these higher quality sensors. The MQ-x sensors that come with the starter kits are relatively useless. I just finished taking 120,000 readings of my lab and your video has given me some great information of things I need to check. Thanks for all you do.
@AndreasSpiess4 жыл бұрын
I will not include the MQxx sensors in my tests as they are made for different gases, I think. And my experiments with them were also not rewarding.
@AnotherMaker4 жыл бұрын
@@AndreasSpiess Yes. The data sheets say some of them measure CO2 but the results were very unreliable.
@neymarjr1292 Жыл бұрын
@@AndreasSpiess how about MQ-131 for VOC measuring and also which dust sensor should be used for this project additionally?
@AndreasSpiess Жыл бұрын
@@neymarjr1292 You can try. I do not know what they really measure... I never used dust sensors. only particulate matter sensors
@charleyfan19082 жыл бұрын
Hydrofluorocarbon is used for fire suppression in most data centres. The gas cylinders are smaller compared to CO2, and safer for people to return.
@AndreasSpiess2 жыл бұрын
Thank you for the additional information!
@albygnigni4 жыл бұрын
Hi Andreas! Do you know the CCS811 VOC sensor? It's the most popular on AliExpress. I've been using it for a while and it is pretty accurate. By the way I have a question, do the sensors you showed need a burn-in for accuracy? Hot plate ones often need a 48hr burn in
@AndreasSpiess4 жыл бұрын
The CO2 sensors do not need burn-in. And I mounted now a CC811 with the other sensors for comparison.
@myounges3 жыл бұрын
@@AndreasSpiess how did that comparison go?
@gnom694 жыл бұрын
Great video! I would be very interested if you can measure co2 or voc (or air particles?) increase while running your 3d printer. Especially PLA/PETG/ABS which we home-makers can use. Anectdotally I‘ve sometimes felt the „meeting effect“ in the beginning when I had the printer stationed in my bedroom.
@AndreasSpiess4 жыл бұрын
I would not expect any increase in CO2. Maybe VOCs are emitted. I will see it in the future...
@thenickdude4 жыл бұрын
@@AndreasSpiess Printing ABS should generate styrene gas which is a VOC - it'd be really interesting to measure the impact of this at various distances from the printer.
@Hessijames794 жыл бұрын
Who doesn‘t feel tired in meetings?
@TheBodgybrothers4 жыл бұрын
Just the spoken word causes people to yawn
@AJB2K34 жыл бұрын
@@TheBodgybrothers *Yawn*
@uwezimmermann54274 жыл бұрын
in meetings minutes are kept and hours are lost
@JUANKERR20004 жыл бұрын
Not just tired but also bored.
@Ed196014 жыл бұрын
There were occasions where I considered shooting myself. Fortunately worked for a company once where meetings were forbidden
@user-uq1kk9mg1c7 ай бұрын
it's really goooood video. Is it ok for output cycle faster and , how to check the fastest rate? i want to see more detail graph
@AndreasSpiess7 ай бұрын
This is an old video. So I do not remember the details :-(
@nashaut76354 жыл бұрын
Exactly what I was looking for! Thanks!
@AndreasSpiess4 жыл бұрын
You are welcome!
@bobapthorpe4 жыл бұрын
This is similar to my first ESP32 project, an atmospheric monitor/logger that measured particulate and combustible gas concentration with a Shinyei PPD42NS and an MQ-2 sensor. It uses GPS for a reference time signal and a BME280 sensor for reference pressure, temperature, and humidity values. I looked into MQTT communications but got distracted by trying to estimate power requirements (was hoping to add solar panels and battery). The particulate sensor uses a resistor as a heating element to move air and particles past the IR sensor and I believe that dominated the power consumption. Search for apthorpe/aerosniff on BitBucket for the code and Fritzing schematic & circuit diagram if you're interested. Thanks for making ESP32 development so accessible; I wouldn't have been able to do that project without your videos :)
@AndreasSpiess4 жыл бұрын
You seem to be quite experienced with sensors...
@arnonroyna44202 жыл бұрын
The little hand @7:01 😆
@AndreasSpiess2 жыл бұрын
:-)
@davesemmelink89644 жыл бұрын
I bought a set of 9 cheap gas sensors a while back but just got around to trying them now. It was my first ESP32 project using more than one ADC input, so I was very surprised and disappointed to find out that if you use WiFi on the ESP32, half the ADC inputs are disabled, and in the case of my DOIT ESP32 DEVKIT V1's, the ADC pins labelled VN and VP also don't work, so I was left with 4 usable ADC pins. I'm considering disabling WiFi, and using Serial Comms to get an ESP32 to use an ESSP8266 to do the WiFi comms to my Node.Red server. Or I could just use 2 ESP32's to handle 8 sensors.
@AndreasSpiess4 жыл бұрын
Or you add an ADS1118 board or another extrernal ADC
@svivs4 жыл бұрын
Thanks for the informative video, just what I needed right now. :-) I’m working on a MQ135 VOC sensor and Sharp infrared dust sensor project. The MQ135 fluctuates a bit in it’s output values so I guess it’s best for short term relative measurements. My program periodically adjusts the “zero” value to compensate.
@AndreasSpiess4 жыл бұрын
It always depends on which gases you are interested in. The problem of calibration is the assumption that you know when the values are lowest and how much lowest is. To determine that, you need a proper sensor. Otherwise all is only guesswork...
@tommihommi14 жыл бұрын
wow, that chinese CO2 sensor finally is an affordable CO2 sensor. I've been waiting for something like that for ages.
@efimovv4 жыл бұрын
Because of this sensor I open world of ESPs and other controllers... But be careful with them - there are 2 versions, and as I understand manual calibration of first one (without B) may "destroy" device - as it need 0 CO2 to calibrate. Second one use more reliable strategy to auto-calibrate and manual calibration assume to 400ppm baseline. And, I have no idea how they differ if you have them in hands...
@wsy23044 жыл бұрын
Great video and look forward to the update particularly how the eCO2 correlate with CO2 readings on extended runs. I currently use a CCS811 for eCO2 and plan to test the SGP30 for similar reasons. Also not sure if I missed but did you send humidity compensation values into the SGP30? Per the datasheet this affects both eCO2 and tVOC reading
@AndreasSpiess4 жыл бұрын
I did not enter the compensation values. The TVOC sensors are anyway showing completely different values as the CO2 sensors :-(
@juweinert4 жыл бұрын
A thing to keep in mind. If it's only about how people feel, measuring CO2 is is right way. Higher CO2 concentrations are what makes us feel bad. But it's not a good indication on wether or not the environment is suitable for you, or healthy. That's a "fun" thing about humans. We indicate if we are suffocating from oxygen depletion by measuring CO2 concentration. You can easily suffocate without noticing if the oxygen get's replaced by something different than carbon dioxide
4 жыл бұрын
In case you get the SCD30 - I made a couple of packages to get it running on a Raspberry Pi in Node.js, Node-RED, and a CLI: * www.npmjs.com/package/scd30-node - Node.js TypeScript API * www.npmjs.com/package/scd30-cli - CLI * www.npmjs.com/package/node-red-contrib-scd30 - Node-RED node Thought some of y'all might find this useful.
@MArifinDobson4 жыл бұрын
As always amazing video master Andreas. I think I will try it in my university classroom, because boy in Physics class we are always tired, I am 100% sure it is not because of the boring subjects but because of the high CO2 concentration. I am curious to try multiple VOC sensor, I will try with the bosch BME680 and SGP30, because CO2 is still above my maker budget. Again thanks for the amazing video!
@AndreasSpiess4 жыл бұрын
I did not find out what the BME680 really measures...
@MArifinDobson4 жыл бұрын
@@AndreasSpiess it measures Temperature, Humidity, Atmospheric Pressure and VOC. Made by BOSCH, I assume it will be good 😁
@maxmund10473 жыл бұрын
The Lambda sensor actually compares the oxigen levels between the exhaust and the outside
@AndreasSpiess3 жыл бұрын
Thank you for the info!
@ramradhakrishnan93824 жыл бұрын
Andreas, Thank you performing the tests that I would otherwise have had to perform myself! By the way, if you want an excellent supply of CO2, you could try Dry Ice, which is nothing but frozen CO2. I believe you can get it from grocery stores, or perhaps from ice cream suppliers. Stay safe!
@AndreasSpiess4 жыл бұрын
Thank you for the tip!
@fibranijevidra3 жыл бұрын
Very informative and interesting video. Thank you!
@AndreasSpiess3 жыл бұрын
Glad you enjoyed it!
@Giblet5354 жыл бұрын
A steady diet of beans and cabbage is very healthy and prevents unnecessary meetings.
@AndreasSpiess4 жыл бұрын
:-))
@pesvids66734 ай бұрын
this was my internship project
@electronicbasics18564 жыл бұрын
thanks for the video
@markj38514 жыл бұрын
Thanks for the great video Andreas. Any idea how "exposed" the sensor needs to be to read accurately? I'd like to add one to my camper which is a small enclosed space, but I'd likely put it in a small project box in a cabinet or out of site location. Would you think the detector would be useful if it's not out in the open, especially since you mentioned CO2 drops down below air?
@sciencoking4 жыл бұрын
Did not expect the wet cat video.
@AndreasSpiess4 жыл бұрын
:-))
@avejst4 жыл бұрын
Impressive review/update Thanks for sharing👍😀
@AndreasSpiess4 жыл бұрын
Thank you!
@dukenukem35684 жыл бұрын
Heads up for Raspberry Pi users concerning the SCD30 as it mentions I2C Clock Stretching in its documentation which could be a problem for Raspberry Pi users who want to use the SCD30 I2C interface, so you might have to use one of the other SCD30 interfaces with a Pi. Andreas perhaps a good video topic would be I2C clock stretching and the Raspberry Pi.
@AndreasSpiess4 жыл бұрын
I think it would be too "special". Most people would not know what it means or what it is for.
@brunobastos55334 жыл бұрын
lambda sensors on cars only work accurately at high temperature
@AndreasSpiess4 жыл бұрын
I did not know that the only work on high temperatures. Thanks!
@LawpickingLocksmith4 жыл бұрын
and if you drive an Opel they go kaputt a lot...
@coffeecuppepsi4 жыл бұрын
yeah i'd like to use induction heating to get the sensor up to temperature, then turn off the hf during a reading... chemical sensors are expensive and need to be replaced fairly regularly
@unmountablebootvolume4 жыл бұрын
@@coffeecuppepsi You might also consider looking at lambda sensors with built in self regulating heaters, but be aware that they get veeeeeery hot on the inside(up to 700°C) and also quite hot on the outside(the metal outside is only seperated from the 700°C inside by a little piece of ceramic) so you need to isulate them and limit the airflow or you will cool the sensor down too far (because the heater is quite weak on many, as it is only made to hold the temp. of the sensor at high gas- /airflows when the gas is already at a similar temp.) , wich will badly mess up the readings.
@Ownedyou4 жыл бұрын
Is that a Surface tablet? They seem to be cool but pricey... Is it worth it?
@AndreasSpiess4 жыл бұрын
This is my business laptop. For me it is ok. Small and light.
@steliosstamatakis844 Жыл бұрын
Can you please test also Scd41 sensor and exploriR-M sensor in humidity environment ?It is a good test..
@AndreasSpiess Жыл бұрын
The Scd41 works well and according to the datasheet. You can trust Sensirion ;-)
@mr.b.15894 жыл бұрын
We started a project in our school with a small co2 "traffic light" on an e-ink display. We are on our way to setup one sensor (with temp and hum) in every room and show the data in Grafana on a monitor in every floor. The VDE gave us 2000€ for this project. If you are interested in, contact me.
@AndreasSpiess4 жыл бұрын
Very good. It would be interesting if the project is well documented (in English) and usable for others.
@mr.b.15894 жыл бұрын
@@AndreasSpiess We will. The documentation will be made with Bookstack.
@erikschatz3484 жыл бұрын
Ein gutes Schul-Projekt: bei der meist gegebenen Weitläufigkeit wäre Kommunikation über LoRaWAN angebracht.
@AndreasSpiess4 жыл бұрын
Wenn man die Messzahlen nicht direkt im Schulzimmer zum Lüften braucht: Sicher
@Parapascal4 жыл бұрын
This topic is on the agenda now! I will build one for my school. Which sensor should I buy now?
@AndreasSpiess4 жыл бұрын
For shure a true CO2 sensor. The others do not display real CO2 values.
@Parapascal4 жыл бұрын
@@AndreasSpiessPrima, danke. Habe einen MH-Z19 zum testen gekauft. Werde ihn wohl nicht mit Batterien betreiben können. Aber ich plane ihn in mein bestehendes influxdb/grafana Setup per lora einzubinden. Was denkst du über die Montagehöhe des Sensors. Am besten auf Kopfhöhe der Schüler oder?
@AndreasSpiess4 жыл бұрын
Die Höhe must du probieren. Soviel ich weiss ist Co2 schwerer als "Luft".
@beware_the_moose4 жыл бұрын
I'd like to see one on the PMS5003 if you feel like doing it, it's a really solid PM2.5 sensor
@AndreasSpiess4 жыл бұрын
Particular Matter sensors have been covered elsewhere and are (hopefully) more a problem of the outside air in crowded areas. Where I live it was boring. Nothing to see...
@beware_the_moose4 жыл бұрын
@@AndreasSpiess I live on a main road; cooking causes most of the pollution in our house even still. I was surprised! The other thing, most people out there on KZfaq are using a particle sensor that doesn't work..the Sharp brand one and equivalents. It's not designed for this job and reads out garbage, but they all use the same code! And it puts out nonsense! The code doesn't work at all. So it's a more interesting topic than it may appear.
@kevinwalters51603 жыл бұрын
@@beware_the_moose Cooking is a big surprise, my PMS5003 goes nuts if I fry bacon and it's not even in the same room. I'm about to get a Sensirion SPS-30 which may give better output for PM2.5/PM10 than Plantower's.
@Snofperiment4 жыл бұрын
@andreas spiess I am a biology teacher. And yes air quality is important for staying focused. Would be interesting to build with students. I prefer blynk platform to read data since students can easily work with that. I already have nodemcu + supplies, just need to order the sensor.
@AndreasSpiess4 жыл бұрын
many streets lead to Rome as we say here ;-) Good luck!
@Snofperiment4 жыл бұрын
Dear Andreas, thanks. I've been to Rome already. Assisting you in a project would be much more fun;)
@___Q-bot Жыл бұрын
16:30 could you use a can of soft drink or sparkling water to obtain the CO2?
@AndreasSpiess11 ай бұрын
This should be possible.
@refusneant4 жыл бұрын
thanks ,clear demonstration
@AndreasSpiess4 жыл бұрын
You are welcome!
@landstreicher97264 жыл бұрын
A nox sensor would be useful to detect the dirty air in cities. Especially in the cold season, there are inversion weather conditions. Poison gases accumulate on the ground, so that it stinks terrible, so you better keep the window closed. Btw. LPG does not release nox and costs less than half its consumption.
@AndreasSpiess4 жыл бұрын
This video was about inside air. I once measured our outside air. It was very boring where I live...
@hanskobischraaner65513 жыл бұрын
I am an absolut Beginner in electronics. I have to implement a MiCS-2714 or something similar in our weather-sensor. So i searched for it on KZfaq and found you. It's funny, that we live not even 10km apart. Now I have a huge problem with the Sensor. I do not have your Cat for the calibration process. Could you please tell her to come over, cause I'm pretty lost with this topic. Sensors and I2C ADCs and so on, not my world.
@AndreasSpiess3 жыл бұрын
:-)) I usually try to cut the problem into its part and solve one problem after the other: Micro, ADC, sensor. Like that I have less "moving parts". Or you buy an I2C sensor which has the ADC built-in. That is my preferred way...
@thedanyesful Жыл бұрын
Couldn't you calibrate by spraying some nitrogen across the sensor for a few minutes until it reads 0ppm?
@AndreasSpiess Жыл бұрын
I do not know. "Calibrating" it with the outside air is ok for me.
@shamrock19614 жыл бұрын
I would think measuring oxygen levels would be a good idea. Perhaps as a control. If O2 levels are low I would think that would have an effect on CO2 and other gases being.measured. Low 02 means there is a not a good supply of good air coming into a room. A question of why would almost beg for an O2 sensor as well.
@AndreasSpiess4 жыл бұрын
So far I did not see any O2 sensors on AliExpress.
@anandmoon57014 жыл бұрын
Plant more indoor plants to compensate these gas in your work place and see the difference.
That other sensor you showed is not a German company, but a Swedish company SenseAir. The sensor you show is the S11, or Sunrise sensor. You can see the source code to make it working here: github.com/letscontrolit/ESPEasy/blob/mega/src/_P052_SenseAir.ino It supports both the S8 and the S11. The S11 can also be set to I2C using some resistors, so maybe you had it wired incorrectly? About the "calibration" of the sensors. Please keep in mind you need to have the sensor placed in a well ventilated room (not outside) to determine the 400 ppm level. You want to make sure it is in the same conditions as when you use it (room temperature and humidity) and also make sure there is no direct sunlight on the sensor or placed near a source of IR light like a heater.
@AndreasSpiess4 жыл бұрын
Thank you for the correction. I got the sensor prewired from a viewer who was able to use it. But I have to investigate further. It is prewired for i2c and it answers...
@TD-er4 жыл бұрын
@@AndreasSpiess I have not yet used the sensor in I2C mode, but I guess it is quite similar to look up register values. If you wire it for UART, you can just use it via Modbus RTU.
@garyseaman61054 жыл бұрын
Great video thank you. If i wanted to monitor air quality in my living room with a log burner, would these sensors work please?
@AndreasSpiess4 жыл бұрын
These sensors do what I described. You have to decide if you are interested in the values they provide.
@tobiasheeb97214 жыл бұрын
I'm a big fan from east switzerland. I just bought a sensirion scd30 and would like to battery operate it. I planed to frequently switch them on with a TPL5110 Nano Power Timer to measure at an interval of 1 min, send the result to an mqtt server and then power off for the next minute. Do you have any suggestion why this could be a bad idea?
@AndreasSpiess4 жыл бұрын
Look how long it has to run till it gets good results... If I remember right they need some time to stabilize.
@ChrisPrefect4 жыл бұрын
Leider schaffe ich es nicht das MH-Z19 Arduino-Sketch zu kompilieren. Ich habe das Modul "FreeRTOS" installiert, aber Arduino meldet trotzdem "MH-Z19:11:31: error: freertos/FreeRTOS.h: No such file or directory". Wie wurde der Sensor an den ESP8266 angeschlossen? Merci!
@AndreasSpiess4 жыл бұрын
Dieser Sketch läuft nur auf einem ESP32, weil ich den Sensor an Serial2 angeschlossen habe. Sonst musst du Softserial verwenden.
@valiza1234 жыл бұрын
How did you know I had problems with my sensor. CCS811 now I know thanks
@AndreasSpiess4 жыл бұрын
You are welcome!
@Olavotemrazaodenovo4 жыл бұрын
Excelente trabalho
@AndreasSpiess4 жыл бұрын
Gracias.
@ArthurDent754 жыл бұрын
Why do you save your MQTT messages in InfluxDB through NodeRed? You can install Telegraf along with InfluxDB and automatically save all your MQTT messages (or just some topics) in the InfluxDB Database.
@AndreasSpiess4 жыл бұрын
I use node red for many things and I like it. No need to have another tool for me.
@grantaylward71254 жыл бұрын
Great project, I am also using an SGP30 to measure eCO2. Your values are much smoother than mine. I think my calibration did not go as well- I simply let it run for 12 hours which is what I thought the documentation outlined. What calibration steps did you take to get this good data output?
@AndreasSpiess4 жыл бұрын
I average the values.
@nektarioskourakis83312 жыл бұрын
Great job as always !!! thanks! Can you recommend a specific sensor-not too expensive- to study photosynthesis? If i get it wright eCO2 sensors are excluded.
@AndreasSpiess2 жыл бұрын
Yes, you need "real" CO2 sensors if you need to measure Co2. The Sensirion sensors and the Chinese ones were good.