ESP8266 Air quality sensor

[jvdz]

I am running an Wemos D1 + MH-Z19b since a few months now with a modified version of ESPEASY I made as described here: https://gathering.tweakers.net/forum/li ... 9#52624079
This Wemos also has 2 LUX sensors, a DHT22 Sensor for Temp&Humidity and a BMP180 Barometer (Presure).
All these devices are directly updated via the build in options of this modified ESPEASY version by a URL call.
The devices are all setup in Dummy hardware which you first need to create yourself and then use the IDX in the ESPEASY definition for the device:

Knipsel.PNG (40.11 KiB) Viewed 9857 times

The graph created by the MH-Z19b/CO-20 looks like this:

Knipselb.PNG (246.72 KiB) Viewed 9857 times

The thread I linked is a good place to find some information about the usage of this setup.

Jos

[LouiS22]

Because I'm new here I say Hello to everyone,

The air quality sensor made of an ESP8266 and an MH-Z19 is true to me.
What I understand is that you can use and pair this combination of stand alone with Wi-Fi to my Raspberrypi on which Domoticz stands?
Now I saw the print of a CO2 chart, and I want that too.
But on the same print, I see hardware as the Volcraft co-20 in Domoticz.
Can anyone explain how this is? Is it that if you download the software by itself, if you have Volcraft in Domoticz?

Thanks in advance,

Topcase1

You have to create a dummy sensor in Domoticz, then create a CO2 virtual sensor within. Note its IDX, that's what you have to feed from ESP8266 (for example Espeasy).

[Topcase1]

Jos en LouiS22, Thanks!

Topcase1

[nixalsschrott]

I am running an Wemos D1 + MH-Z19b since a few months now with a modified version of ESPEASY I made as described here: https://gathering.tweakers.net/forum/li ... 9#52624079
.....

It sounds very interesting and is also very close to what I am searching for.
Since your link does not contain english or german description it would be very helpful, if you could provide a little howto with component list and steps to set up the hard- and firmware.

Kind regards
matty

[jvdz]

Hi Matty,

No problem. We can do that here so others can also benefit from it... and maybe later convert that into a Wiki page once we have nailed down the appropriate process.
So lets start simple and work our way into the details depending on how far you are already.
Components used:

• Wemos D1 mini - https://wiki.wemos.cc/products:d1:d1_mini
• MH-Z19(b) (Either A or B version will work. I have a B version)
• ESPEasy - Latest Mega version will work but won't update via HTTP JSON with the standard settings. My version does work with JSON. So the below only works with my GIT version at this moment.

Assembling
Connect the following:
MH-Z19 Tx → Wemos pin D5
MH-Z19 Rx → Wemos pin D6
MH-Z19 gnd → Wemos gnd pin
MH-Z19 vin → Wemos 5V pin (Only for MHZ19B, else 3.3V if I remember correctly!)

Loading ESPEASY
Either I can provide the bin to load or you can build it yourself by setting up the following:Source code development
Load the Bin file either from Atom or the load process describe here.


Add Airquality device to Domoticz:
Goto the Domoticz webpage and select: Setup/Hardware.
Add A dummy Sensor:

air0a.PNG (57.06 KiB) Viewed 9801 times

air0b.PNG (11.07 KiB) Viewed 9801 times

Make a note of the created device IDX found in in Setup/Devices

air0c.PNG (52.83 KiB) Viewed 9801 times

Continue Next post (can only attach 3 images each post)

[jvdz]

Configuring ESPEasy:
Goto the webpage of the Wemos/ESPEasy unit and do de basic configuration as described in this page.
Define the Domoticz server under the controllers Tab:

AIR1.PNG (30.02 KiB) Viewed 9800 times

and fill in the appropriate information to connect to your Domoticz server.
Define the Device is the Devices tab:

air2.PNG (49.95 KiB) Viewed 9800 times

.. and fil in the field as shown and use the Found IDX of the domoticz device in the "Send to controller IDX field.

You should be in business after you saved this.
Under the Tools/LOG option in ESPEASY you find information about the steps ESPEASY does and when it receives information.
This is the log I have and you see also the MHZ19 in there:

air3.PNG (64.13 KiB) Viewed 9800 times

Shoot when you have questions.
Jos

[nixalsschrott]

Dear Jos,

really fast reply - thanks a lot.
I need some time to proceed since I am going to order the parts from China, delivery will need approximitely at least 2 weeks.

Regarding the component list you also mentioned DHT22 and GY-68 BMP180 before. Do these sensors also work within this project (connect to same PCB)? Then I would add this parts to my order.

Kind regards
matty

[jvdz]

Yes they do. I've also made some changes in my port of the ESPEASY software to support direct update of the of the dummy BMP180 sensor in Domoticz using the standard HTTP config with IDX.

Jos

[LouiS22]

[*]ESPEasy - Latest Mega version will work but won't update via HTTP JSON with the standard settings.

Actually it works, you have to define a rule, then it's ok. Of course your solution is much more elegant

One question though: have you noticed any "not stable reading" error messages? I have it from time to time.

[jvdz]

[*]ESPEasy - Latest Mega version will work but won't update via HTTP JSON with the standard settings.

Actually it works, you have to define a rule, then it's ok. Of course your solution is much more elegant

Correct, hence my comment that it doesn't work with the standard settings for IDX and Domoticz host.

One question though: have you noticed any "not stable reading" error messages? I have it from time to time.

That won't happen on my setup as I have a mh-z19b version, which doesn't supply the S value, so that is set to 0.
That actually was the reason I made my own version of ESPEASY, since the standard version at the time would always come back with that warning and others had the same issue with the b variant.

Jos

[LouiS22]

[*]ESPEasy - Latest Mega version will work but won't update via HTTP JSON with the standard settings.

Actually it works, you have to define a rule, then it's ok. Of course your solution is much more elegant

Correct, hence my comment that it doesn't work with the standard settings for IDX and Domoticz host.

One question though: have you noticed any "not stable reading" error messages? I have it from time to time.

That won't happen on my setup as I have a mh-z19b version, which doesn't supply the S value, so that is set to 0.
That actually was the reason I made my own version of ESPEASY, since the standard version at the time would always come back with that warning and others had the same issue with the b variant.

Jos

Never noticed there's a B variant (mine is without B - and that's also producing the error message).

[jvdz]

You can check the value of S when you check the ESPEASY values for the device.
Anything below 64 is considered "unstable" in the ESPEASY software for the A version, and will trigger this message.
TD-er made several changes lately for the standard version of ESPEASY in which this piece of code does the checking for S. It nicely explains the usage of it with the also included delay filter option:

Code: Select all

if (s > 0 && s < 64 && filterValue != PLUGIN_049_FILTER_OFF) {
    // Not the "B" version of the sensor, S value is used.
    // S==0 => "B" version, else "A" version
    // The S value is an indication of the stability of the reading.
    // S == 64 represents a stable reading and any lower value indicates (unusual) fast change.
    // Now we increase the delay filter for low values of S and increase response time when the
    // value is more stable.
    // This will make the reading useful in more turbulent environments,
    // where the sensor would report more rapid change of measured values.
    difference = difference * s;
    difference /= 64;
    log += F("Compensate Unstable ");
    filterApplied = true;
  }

This code is executed when the delay filter is off and is the old behavior:

Code: Select all

case PLUGIN_049_FILTER_OFF: {
      if (s != 0 && s != 64) {
        log += F("Skip Unstable ");
        return false;
      }
      filterApplied = false;
      break;
    }

I am not using this version so have no real experience with it, but can only say that the B version I have seems to be pretty stable in its readings.

Jos

[LouiS22]

You can check the value of S when you check the ESPEASY values for the device.
Anything below 64 is considered "unstable" in the ESPEASY software for the A version, and will trigger this message.
TD-er made several changes lately for the standard version of ESPEASY in which this piece of code does the checking for S. It nicely explains the usage of it with the also included delay filter option:

Code: Select all

if (s > 0 && s < 64 && filterValue != PLUGIN_049_FILTER_OFF) {
    // Not the "B" version of the sensor, S value is used.
    // S==0 => "B" version, else "A" version
    // The S value is an indication of the stability of the reading.
    // S == 64 represents a stable reading and any lower value indicates (unusual) fast change.
    // Now we increase the delay filter for low values of S and increase response time when the
    // value is more stable.
    // This will make the reading useful in more turbulent environments,
    // where the sensor would report more rapid change of measured values.
    difference = difference * s;
    difference /= 64;
    log += F("Compensate Unstable ");
    filterApplied = true;
  }

This code is executed when the delay filter is off and is the old behavior:

Code: Select all

case PLUGIN_049_FILTER_OFF: {
      if (s != 0 && s != 64) {
        log += F("Skip Unstable ");
        return false;
      }
      filterApplied = false;
      break;
    }

I am not using this version so have no real experience with it, but can only say that the B version I have seems to be pretty stable in its readings.

Jos

Thanks, I did a custom build from github yesterday evening with the latest modifications - will see how it performs. There's indeed new options to customize ZH19 behaviour - even for the "old" version.

[Igrek]

Thanks, I did a custom build from github yesterday evening with the latest modifications - will see how it performs.

Hello!
This plug-in gives out three values, the dummy Sensor Co2 does not accept such.
Which Domoticz sensor did you use?

[LouiS22]

Thanks, I did a custom build from github yesterday evening with the latest modifications - will see how it performs.

Hello!
This plug-in gives out three values, the dummy Sensor Co2 does not accept such.
Which Domoticz sensor did you use?

Dummy CO2, but I'm using it with a rule created within ESPEasy (http push into Domoticz). Let me know if you need it. BTW I only use the PPM value.

[Igrek]

Dummy CO2, but I'm using it with a rule created within ESPEasy (JSON and push the value into Domoticz). Let me know if you need it. BTW I only use the PPM value.

Yes, I also need only PPM value!
Now I receive the text and run parse the LUA script.
Sure that there is a way easier...
I need it!
Ta!

[jvdz]

Just enable the Rules in ESPEasy and add this rule:
Where:
<MHZ19> = Devicename of the MHZ19 unit in ESPEASY
<DomoticsIP> = IP address of your domoticz server
<port> = port used by your domoticz server
<IDX> = The IDX of the device in Domoticz

Code: Select all

on <MHZ19>#PPM do
  SendToHTTP,<DomoticsIP>,<port>,/json.htm?type=command&param=udevice&idx=<IDX>&nvalue=[MHZ19#PPM]
endon

The rule will be started each time an new value arrives and prerform the url.

Jos

[LouiS22]

Just enable the Rules in ESPEasy and add this rule:
Where:
<MHZ19> = Devicename of the MHZ19 unit in ESPEASY
<DomoticsIP> = IP address of your domoticz server
<port> = port used by your domoticz server
<IDX> = The IDX of the device in Domoticz

Code: Select all

on <MHZ19>#PPM do
  SendToHTTP,<DomoticsIP>,<port>,/json.htm?type=command&param=udevice&idx=<IDX>&nvalue=[MHZ19#PPM]
endon

The rule will be started each time an new value arrives and prerform the url.

Jos

Indeed, with the below correction: udevice goes first, then type!

Code: Select all

on CO2TEST#PPM do
   SendToHTTP 192.168.0.19,8080,/json.htm?param=udevice&type=command&idx=2894&nvalue=[CO2TEST#PPM]
endon

(my device name is CO2TEST, you can replace it with the one you like)

[jvdz]

Pretty sure it worked that way before I changed my ESPEASY version, which is to be expected.

[Thelion]

Hi,

I'm following this topic and I'm about to order the components, but I noticed there is a 0-2000PPM and a 0-5000PPM version of the MH-Z19B

I really hope the air quality never gets in the 5000PPM range, but more range is better, right?