Air Quality unit - which devices are best?

[localhorst]

Hi everyone,

after successfully changing my CO2 measurement units from SenseAir S8 to SCD30 (who are working great!) and my unit with the DACs - thank you all so much for your great support! - , my wife is having a request to me.
She likes to have an air quality unit for her office. Her office is in a place with heavy truck traffic and there are always arguments with her colleagues about the air quality in the office - if windows should be opened or not, etc.
Currently I have 5 D1 mini boards ESP8266 already here. And the Senseair left over for CO2.
Now I'm planning to create a complete new unit with a LCD2004 display. Therefore I'll invest the time to create a complete new and beautiful housing.
Soon I'd like to place an order in AliExpress for sensors and displays.

I'd like to ask you for your recommandations for sensors. What are from your experience the best and most reliable, supported by ESPEasy?
Apart from CO2, I'd like to measure:

• Temperature (BMP280?)
• Humidity (BMP280?)
• Nitrogen dioxide NO2 (SGP41?)
• Fine dust (PM₁₀ / PM₂,₅) (PMSx003 / PMSx003ST?)
• Carbon monoxide CO
• Ozone O3
• Sulfur dioxide SO2

As some sensors are combining different sensors, what could be my perfect mixture?

Thank you very much and have a nice weekend!

Kevin

[Ath]

For starters, I'd suggest to use a TFT Color display (either the ILI9341 (try to avoid the ILI948x models...) or ST77xx models will do) over the LCD2004, as TFTs can show much more than a couple lines of text only.
And also, an ESP32 if preferable over an ESP8266, as the ESP8266 builds do not support all features of the graphics driver because of .bin size limitations.
Most likely, using a specialized set of plugins, a custom ESPEasy build will be what you need, to combine most of the devices in a single build (many of them are in the Climate build, but the TFTs aren't), so that should be doable, including those in a Custom build.

There is also a somewhat newer Sensirion SEN55 (shop link) combined sensor, that has many of the sensors you want to use, but has some overlap with the SenseAir S8, but the SEN55 doesn't yet have support in ESPEasy... (sorry for the teaser )

Can't say much about the sensors, as I'm not really actively using/monitoring/comparing those.

[Ath]

For the 'Gases' support we have a plugin for the MQ-xxx sensors, CH4, CO2, CO, H2, LPG and Alcohol.

[localhorst]

For starters, I'd suggest to use a TFT Color display (either the ILI9341 (try to avoid the ILI948x models...) or ST77xx models will do) over the LCD2004, as TFTs can show much more than a couple lines of text only.
And also, an ESP32 if preferable over an ESP8266, as the ESP8266 builds do not support all features of the graphics driver because of .bin size limitations.

Great, thank you!
The display should be big, as the unit should be able to act as standalone. For the first shot, I'm planning to build two units. One for us at home, one for my wife's office. In the office it will be a standalone, at home it'll be integrated in ioBroker - but should still have a big display.
But as this will be created from scratch - let's choose the hardware with the least headache. Which ESP32 board would you recommend - with enough storage to avoid the need of custom builds / able to flash the full ESPEasy package with all plugins?
Which TFT would you think is best?

There is also a somewhat newer Sensirion SEN55 (shop link) combined sensor, that has many of the sensors you want to use, but has some overlap with the SenseAir S8, but the SEN55 doesn't yet have support in ESPEasy... (sorry for the teaser )

No need to be sorry, the teaser somehow reminds me of the start of the DAC project.
Very interesting sensor! And I've recognized Sensirion as a quite good brand so far. It seems to be no chance to get it on AliExpress, but I could get it without any problems in Germany. The price seems to be fair for me, in hindsight of this package of sensors.

For the 'Gases' support we have a plugin for the MQ-xxx sensors, CH4, CO2, CO, H2, LPG and Alcohol.

So one of those together with the SEN55 should nearly cover all wished sensors I guess?

[localhorst]

Would a WT32 SC01 as a combined unit of TFT and ESP32-S3 with 16MB flash maybe a good idea?

[Ath]

Would a WT32 SC01 as a combined unit of TFT and ESP32-S3 with 16MB flash maybe a good idea?

That display, of the WT32-SC01Plus (the S3 unit) is not yet supported. Not sure when that'll be included, as it will (probably) require a new plugin, and uses quite some GPIO pins.

The somewhat older model, the WT32-SC01 display is supported, and the touch screen is in a PR (that's been open for quite some time already, still some finishing touches to do on the web-UI, but technically working OK already).

Edit: Changed link to 16MB model

[localhorst]

Edit: Changed link to 16MB model

Great, thank you! On AliExpress I cannot find a WT32-SC01 without Plus and with 16MB - annoying. On Alibaba, from your link, it would be end of March, when the units would arrive. AliExpress is getting it here usually within 2 weeks.
Well, if there is no alternative, I have to patient...

How about the usage with this display and ESPEasy? I guess only text, color, background color is possible? Or could I use graphics as well?

[TD-er]

About the mentioned sensors.

Bosch has the BME280 and BMP280.
The difference is that the BME has humidity.
Make sure to pick the 3V3 version as lots of sellers also sell boards which can only operate on 5V.

The Plantower sensors (PMSx003) are fine.
Make sure to also read the documentation page on them as there is lots of information on how to interpret the data.
The PMSx003ST version also measures Formaldehyde.
As always, measuring is knowing, only if you know what you're measuring.

With that expression in mind, you may want to reconsider measuring NO2, O3 and SO2 as it can be quite hard to make proper measurements on those.
The MQ-xxx sensors mentioned by Ton are indeed intended for those gasses, but they don't just react to a single gas.
Also there are VOC sensors (often also marketed as "eCO2" sensors) which also measure volatile gasses.
But it really requires extensive knowledge on how to correlate all those readings to draw conclusions about actual concentrations.
For example you can control the heating period of such sensors so they do react differently on some gasses and assuming the concentrations remained the same you can derive concentrations of various gasses.

So just to get an idea of presence of volatile gasses, you can use those VOC sensors (e.g. CCS811).
Those MQ-xxx sensors may help to differentiate a bit more to get some idea of which gasses might be the most likely gas you're smelling.
But it is by no means possible to get exact readings without extensive calibration and lots of knowledge about the response curves of those sensors (including the effects of ageing of those sensors)

[localhorst]

As always, measuring is knowing, only if you know what you're measuring.

Absolutely true!
Easy with CO2, but for other gases, I have currently no idea.

With that expression in mind, you may want to reconsider measuring NO2, O3 and SO2 as it can be quite hard to make proper measurements on those.

I absolutely agree - and it doesn't have to be measured. Would have been nice, but with this technical background, it obviously doesn't make sense (at least to me).

But maybe the Sensirion SEN55 would be already with its particulate matter, humidity, temperature, VOC and NOx together with the SenseAir S8 / CO2 already a very good unit, to judge the air quality in general.
As from what I read from the specs, it's already factory calibrated and ready to use. The temperature and humidity are in the air stream of the fan, so I guess will be pretty accurate as well.
And the SenseAir S8 with its single channel, should do a good job in the office environment, as for example during the weekends and nights nobody is there.

[Ath]

How about the usage with this display and ESPEasy? I guess only text, color, background color is possible? Or could I use graphics as well?

With these plugins I've introduced a common command set, that, besides writing text in colors, can draw lines, circles, boxes, triangles etc. in any color (65535 colors (16 bit) max.) and you can load .bmp files (24 bit colors, the most common format, scaled down to 16 bit) from local storage, so that would be a good reason to have a 16MB unit, as then you can have up to 8MB of the flash for the file system when using a MAX_16M8M build.

The touch plugin (P123) supports touch-areas, buttons, sliders, and an optional menu-like structure for the buttons. (Documentation I still have to write...)

[localhorst]

P123 - wow, that sounds very cool!

Well, then I have to find a quicker delivery for the boards for a reasonable price, or simply have to wait until end of March (which would be hard).

[localhorst]

Just a quick update:
I've ordered 2 WT32-SC01 with 16MB - better I'm patient and get the right stuff.
As well I've ordered 2 SEN55 including cables.
Now waiting for the hardware, starting with the design for the housing at some point.

[localhorst]

Regarding the SEN55:
The documentation is giving a real good impression already, relativizing the high price a bit and is giving a good quality impression.
3D model available and especially the Mechanical Design and Assembly Guidelines for SEN5x is really helpful, to make the design decisions for the whole unit.

[localhorst]

The touch plugin (P123) supports touch-areas, buttons, sliders, and an optional menu-like structure for the buttons. (Documentation I still have to write...)

Quick question Ton:
Are there any problems with this plugin expected, if I turn the display by 90 degrees?
I came to the point, that I think this would be the best way, design and hardware / connection wise:

IMG_2832.jpeg (2.27 MiB) Viewed 2716 times

IMG_2835.jpeg (2.24 MiB) Viewed 2716 times

[Ath]

Rotating it should be fine, both the TFT and Touch plugins support that (and AFAIR, the TFT is in portrait mode by default...).
After initially setting things up in landscape mode, it would be a challenge to change that to portrait later, but when starting in portrait mode it's just as easy as it should be (I hope ).

[localhorst]

Thank you Ton!
Then I’ll proceed with a portrait mode design for it.
Already the USB connection for the board would make it very / unnecessary wide, if in landscape mode. Wouldn’t look nice in the end.
As well the (beefy) SEN55 is nearly the same width in portrait, so right on. The S8 will be above the SEN55 then, there will be enough space.

[chemmex]

From the sensor side, I would recommend SCD40/41 for CO2, temperature and humidity, they are almost as precise as SensAir while cheaper, more compact, and less power hungry. SEN54/55 can be added for PM and VOC measurement, or it can be PMS7003 and SGP40/41 combo.
I had to flash Tasmota to test SEN55 - well, it works, and PM2.5 readings are quite identical to those of PMS7003 which I massively use in my designs.

[chemmex]

There is also a somewhat newer Sensirion SEN55 (shop link) combined sensor, that has many of the sensors you want to use, but has some overlap with the SenseAir S8, but the SEN55 doesn't yet have support in ESPEasy... (sorry for the teaser )

Actually, there's no overlap between SEN55 and SenseAir S8 as S8 is basically CO2-only sensor, it has temp and humidity outputs only for auxiliary purposes.

[Ath]

Ah, well it's often a bit confusing with all the acronyms used, that I tend to keep mixing up in my head

My SEN55 is due to arrive today; after the current project I'm working on I'll probably start to implement that (priorities, priorities...).

[localhorst]

From the sensor side, I would recommend SCD40/41 for CO2, temperature and humidity, they are almost as precise as SensAir while cheaper, more compact, and less power hungry.

Actually, there's no overlap between SEN55 and SenseAir S8 as S8 is basically CO2-only sensor

Yes, this is why I'll add the SenseAir S8.
As I have 4 SenseAir S8 left over, I'll add one of those for CO2. For the unit intended to run here at home, I'll pass through the CO2 value to the TFT display from my (dual channel) SCD30 CO2 unit - which will be standing side by side.

SEN54/55 can be added for PM and VOC measurement, or it can be PMS7003 and SGP40/41 combo.

The SEN55 are already ordered and should be here on this Thursday. Once Ton is having the time, we can start testing. But no rush.

PM2.5 readings are quite identical to those of PMS7003 which I massively use in my designs

This is good to know, thank you! I expect the SEN55 to be of good quality and reliable readings.

So, currently the units are planned to consist of:

• WT32-SC01 (16MB)
• SEN55
• SenseAir S8

Who will deliver:

• Temperature
• Humidity
• Fine dust (PM₁₀ / PM₂,₅)
• NOx
• VOC
• CO2

That should be a nice air quality unit.

I've ordered 2 WT32-SC01 with 16MB - better I'm patient and get the right stuff.

Meanwhile they are on the way - already waiting for outbound release of China.
I don't know, maybe they'll arrive way before end of March.

[TD-er]

[...] after the current project I'm working on I'll probably start to implement that (priorities, priorities...).

Hmm, this coming from mister "I-have-a-dev-window-per-open-Git-checkout"...
That's really new to me that you do projects serialized

[TD-er]

About the SEN55
I never used one myself, but I really doubt they actually measure particles over 2.5 micron.
None of the affordable dust particle sensors do and all just extrapolate readings for > 2.5 micron.

So I still strongly advice to read the docs for PMSx003 as it has a lot of info about reading dust particles in general, which probably will fully apply to this SENS55 sensor.

[Ath]

Hmm, this coming from mister "I-have-a-dev-window-per-open-Git-checkout"...
That's really new to me that you do projects serialized

[localhorst]

So I still strongly advice to read the docs for PMSx003 as it has a lot of info about reading dust particles in general, which probably will fully apply to this SENS55 sensor.

Very interesting indeed! As well the linked video.

but I really doubt they actually measure particles over 2.5 micron.
None of the affordable dust particle sensors do and all just extrapolate readings for > 2.5 micron.

Yes, seems so:
From this Sensor Specification Statement document / Page 4 / "1.6 Performance of PM4 and PM10":

Therefore, the PM4.0 and PM10 outputs of Sensirion’s PM sensors are estimated from PM0.5, PM1.0 and
PM2.5 measurements considering typical aerosol profiles instead of being based on “real” raw data events from
large particles.

[TD-er]

Nice of them to add this statement.
So you know your setup will probably differ from the "typical aerosol profile" and thus should be taken with a grain of salt (which is also too big for the sensor )

[localhorst]

Two SEN55 in da house - ready to rumble, eh... test!

I've ordered 2 WT32-SC01 with 16MB - better I'm patient and get the right stuff.

Meanwhile they are on the way - already waiting for outbound release of China.
I don't know, maybe they'll arrive way before end of March.

Those are already announced to DHL. If they are not going by ship but per plane, they really should be here this month.

[TD-er]

There is now Chinese NewYear, so I wonder how much delays this may cause.

[localhorst]

Take a look what just arrived.

IMG_2977.jpeg (2.1 MiB) Viewed 2138 times

So the hardware is complete.

*edit*
The little cutout in the middle on the left:
is it a light sensor or something? Which needs free visibility in the housing design?

[TD-er]

Just curious, is there actually a sensor mounted behind the "eye" on the top of the display (when in portrait mode)? (left on the picture)

On the older revisions of those the datasheet and schematics mentioned some presence sensor there, but there was none.

[localhorst]

Ah, I’ve edited the post before.
But here is a macro shot of this what seems to be a sensor:

[TD-er]

Looks more like solder pads and PCB silkscreen
So no sensor in this revision too...

[Ath]

Haven't seen any with a sensor in that spot, and it's not mentioned anywhere in the (sparse) documentation.

No need to keep it clear/open, AFAICS.

[bidrohini]

All of the sensors that you have chosen are supported by ESPEasy. I think it's a good list of components. You can also consider CCS811 Air Quality sensor. The CCS811 is from AMS, and can detect a rather wide range of VOCs. Connected to the microcontroller it will return a TVOC reading and the equivalent CO2 reading, over I2C.
https://www.pcbway.com/project/sharepro ... Board.html
The sensor is also supported by ESPEasy: https://espeasy.readthedocs.io/en/lates ... /P090.html

[TD-er]

@bidrohini
Maybe best to not mention "eCO2" as a feature as it is confusing to say the least.
I would rather call it a misleading unit of measure as it implies something to do with CO2.
But it doesn't.
Those VOC sensors measure volatile organic compounds and it is really hard to distinguish what it measures.
For example place a glass with some alcoholic beverage next to the sensor and it will claim to measure extreme high "eCO2" values.

Only in some very specific conditions, the "eCO2" values measured may show some correlation to the actual CO2 levels.
And I can guarantee your situation will very likely not be among those very specific conditions.

[localhorst]

@bidrohini:
Thank you, but the die has been cast already. It's the sensor package of SEN55 and SenseAir S8 for (NDIR) CO2 measurement.
I'm currently printing the 3rd design iteration for the housing.

[localhorst]

I guess the housing is ready, now only data from the SEN55 is missing.

IMG_3019.jpeg (2.28 MiB) Viewed 1830 times

IMG_3020.jpeg (2.12 MiB) Viewed 1830 times

[TD-er]

Looks nice

Didn't know ESPEasy was capable of generating such nice dashboards.
Or have you been really creative with BMPs?

[localhorst]

Didn't know ESPEasy was capable of generating such nice dashboards.
Or have you been really creative with BMPs?

Well...

Bildschirmfoto 2024-02-25 um 11.38.22.png (248.16 KiB) Viewed 1818 times

The background image "himmel.bmp" (full screen resolution 320x480px and really big for the unit) needs some time to load, so this is only done at boot up.
At start of the unit the standard screen lines are loaded and I've set things like build name, IP, etc. After a couple of seconds wait time, himmel.bmp is loaded, after that the rest of the screen.
So it looks like a bootscreen, how it slowly comes up and builds the rest of the screen afterwards.
Once this is done, only the specific lines are updated, when new values are coming in. Works nicely.

[TD-er]

OK, so maybe we should also try to use any PSRAM for this if available, so you don't need to load stuff from the file system when needed.

[localhorst]

Maybe set the priority first in adding more fonts (or less different fonts, bur more font sizes per font). Scaling of fonts doesn't look nice and getting pixely on the TFT.
And that those fonts are able to show characters like e.g ° and m³. Because now I'll have to create a BMP for it.

[TD-er]

Fonts are a bit tricky for lots of reasons.
Maybe it is even better if we document how to make fonts yourself and embed those.
One of the most tricky parts is.... you have to be really really careful to only use "free" and "open" fonts.
And also scaling fonts is also quite hard and time consuming as it can happen quite often that some thin lines completely disappear when using a specific scale. (e.g. at size 8 and 10 is perfectly fine, but 9 gives issues)

[localhorst]

Fonts are a bit tricky for lots of reasons.
Maybe it is even better if we document how to make fonts yourself and embed those.

That sounds like a nice solution. Although I currently have no idea how hard it would be to create those.
But would be nice to upload a font file and just use it, yes.

One of the most tricky parts is.... you have to be really really careful to only use "free" and "open" fonts.

Yes, I know. Already on websites, with disclaimer, where they are loaded from, etc.
But the solution to create them by yourself would solve this problem. As those fonts are then only running on the private units and are not officially provided by ESPEasy.

But generally speaking to the situation right now:
Maybe limit the amount of different fonts now and pick a nice selection. And use the "free space" for the selected ones to add all with 8, 10, 12, etc up to 24 font size. And with special characters like degree, etc, who are commonly used with ESPEasy and its sensors.

[TD-er]

Right now we can't use font files, so it has to be embedded in the binary.
A first step would be to allow to use fonts from the file system and of course a manual/tool to simply create them and test them to see no parts (thin lines or thin openings) are missing.

I think adding a lot of fonts is making things extremely complex as it will easily "explode" in size and complexity as for some displays one font may look a lot better compared to others and you'll never have that one font people like at that specific size... etc.
Also you will always have situations where you're missing that one character. (most fonts don't even have all characters. If they do, all fonts in .ttf would be 10+ MByte in size, let alone if rastered like we use it)

So that would either be something for "self built" setups or loading from file system.

[localhorst]

Right now we can't use font files, so it has to be embedded in the binary.
A first step would be to allow to use fonts from the file system and of course a manual/tool to simply create them and test them to see no parts (thin lines or thin openings) are missing.

That sounds awesome to me!

I think adding a lot of fonts is making things extremely complex as it will easily "explode" in size and complexity as for some displays one font may look a lot better compared to others and you'll never have that one font people like at that specific size... etc.

I didn't mean to add a ton of different fonts. Other way round, only a selection of for example 3. But those with different sizes and the commonly used special characters.
The current situation looks a little erratic. Nice font here, but not available in bigger. Nice font there, but only available in one size. Another nice one with some bigger sizes, but not smaller ones. Handwritten - nice! But not available in bigger and scaling looks not good, etc...

As soon as we would be able to use fonts from the file system, the other already existing fonts could be available as extra downloads. And in general there could be a section for (free) fonts for ESPEasy to download - in best case with community input.

[localhorst]

One question regarding the Expansion board interface, 2.0mm pitch, 2X20Pin of the WT32-SC01:
How do you work with this? Are there any connectors / plugs where the cables can be soldered on (haven't found any)? Or do you just stick male DuPont in there?
What is a clean / proper way to connect the sensors there?

[chromo23]

I guess the housing is ready, now only data from the SEN55 is missing.
IMG_3019.jpeg
IMG_3020.jpeg

Oh.. i missed some interesting things here.
It looks really nice. Could you provide me with an project description. Maybe even as an extra topic. I think this could be also interesting for other people.
I am especially interested in how you did the graphics with espeasy.

[localhorst]

It looks really nice. Could you provide me with an project description. Maybe even as an extra topic. I think this could be also interesting for other people.
I am especially interested in how you did the graphics with espeasy.

Thank you!
Yes, of course I can do it. If it is from interest and needed, I can write a manual how to create the BMPs yourself (with GIMP), as well as provide the rules and the icon set I've created already.
But it's still very much in the making and not clean yet.

As well, I'll publish the 3D models I've created. And I have at least one or two already printed housings from the tryout phase (I'm still in), I can give away to the community for free (just the shipping costs would be nice). It would be a pity to throw those housings away.
But before publishing the 3D models, I'd like to see the SEN5X running (especially hear it running with its fan) - if something needs to be changed because it's resonating with the housing. Maybe I'll already connect power to the SEN55 and hope that the fan will already run. Then I can close the book.

[TD-er]

I'll be interested in the 3D designs too (I do have 3 3D printers here, so no need to ship any prints to me)

[chromo23]

If it is from interest and needed, I can write a manual how to create the BMPs yourself (with GIMP), as well as provide the rules and the icon set I've created already.

No need for a manual in creating graphics (i grew up with photoshop). At least not for me. I am more interested in the process how to get everything in rules aligned.
But no rush... finish you project first..
What program do you use for creating the 3d models?

[localhorst]

I'll be interested in the 3D designs too (I do have 3 3D printers here, so no need to ship any prints to me)

Of course, just let me do a final check with the SEN55 fan running and the noise - if there is any (hopefully not). Then I'll publish them to printables.
And I'll write a manual for the ESPEasy dashboard with the BMP graphics and rules in a seperate thread. And my current iconset to possibly start off from there.

Any ideas regarding this?

One question regarding the Expansion board interface, 2.0mm pitch, 2X20Pin of the WT32-SC01:
How do you work with this? Are there any connectors / plugs where the cables can be soldered on (haven't found any)? Or do you just stick male DuPont in there?
What is a clean / proper way to connect the sensors there?