3D printed box for CO2 Easy

Many of the blog's readers have asked for a 3D printed box for the CO2 meter.

OK, challenge accepted!

I have designed a customised box for 3D printingsimple and easy to print, no need for brackets or bridges.


The main ones in features and benefits of the box, are as follows:

  • Easy to print (without brackets and bridges).
  • Design with thermal dynamics to conduct heat away from the CO2 sensor
  • System of solderless NodeMCU installation (optional)
  • Ready to install a 0.96″ OLED display
  • Prepared for the installation of LEDS for colour-coded displays
  • Prepared for buzzer installation
  • Design of custom vinyl front cover


The box is very easy to print, although, as it has a certain surface area, it can give problems with warping (lifting of the corners) depending on the printer and its settings. when printing with ABS.

I I have printed the prototype with PETGalthough could be done perfectly well with PLA.

In a way, the PLA would be better because it is more stable and the measurements are more accurate.. This is especially important for the NodeMCU pins (I had to rework the holes with a small drill bit).

The box does not bear any stress and is structurally robustThe 10% can be printed with a 10% infill without any problem or risk of it being too flimsy.

The printing time, in my case, has been of approximately two hours. Depending on the printer, speed and desired quality, the printing time can vary considerably.

Print file

I have left the STL file for printing on Thingiverse. You can access it here.

The back cover, which I have not yet designed, is missing.. This is a first version and I will probably make another version with some improvements I want to introduce, so I will take the opportunity to design the back cover already for the new version.

If I didn't make the new version, I would design the back cover for this one.


The video covers the basic details needed to connect the OLED display. For more information, I recommend viewing the article Connecting an SSD1306 OLED display to ESPEasy.

Diagram showing the connections from the NodeMCU to the SSD1306 display.

Diagram with connections from NodeMCU to WS2812 LEDs (Neopixel)

For more information, see the article Connecting and controlling WS2812B LEDs to ESP8266 with ESPEasy.

Diagram showing the connections of the NodeMCU to the MH-Z19 or Senseair S8 module.

Both modules, MH-Z19 or Senseair S8, are compatible in terms of connections, so the connection will be identical.

ESPEasy configuration

Once we have made the connections, we have to configure ESPEasy to recognise the devices and include a few simple rules to behave the way we want them to behave.

Basically, we will have to do the following:

  1. Add the MH-Z19B sensor to ESPEasy
  2. Adding the SSD1316 display to ESPEasy
  3. Add WS2812 LEDS to ESPEasy
  4. Activating the ESPEasy rules engine
  5. Add a rule so that when it is switched on, the LEDs are switched off.
  6. Add a rule to change the colour of the LEDS depending on the CO2 level.

Add the MH-Z19B sensor to ESPEasy

This article, which you are reading, is about the 3D printed box. It is assumed that you already have a working home CO2 Meter. If this is not the case, I recommend you to see the article of the homemade CO2 meter and its video. Here you will find all the necessary details and a lot of useful information.

Adding the SSD1316 display to ESPEasy

The connection of this display is very simple and is explained in detail in the video.

I will not repeat their configuration here, as in the article Connecting an SSD1306 OLED display to ESPEasy you have very detailed instructions on how to connect the display and how to set it up with a very detailed video.

Add WS2812 LEDS to ESPEasy

Connecting WS2812B LEDs to our board and using them with ESP Easy is child's play. Only three connections are required.

Its connection and use are explained in detail in the video below, so you should not encounter any problems.

I recommend you to see the article Connecting and controlling WS2812B LEDs to ESP8266 with ESPEasy where you can find all the connection details, the rules you have to create, etc.

Want to add a buzzer?

The box is prepared for the installation of a buzzer, In article Using a buzzer with ESPEasy you have everything you need for connection and use.

Step-by-step video tutorial

Although the assembly is very simple, and is largely covered in the video of the assembly of the Homemade CO2 meterI have created a video with all the details of how to assemble the meter in a box, with specific instructions for connecting and configuring the OLED display and LEDs.

In it you will find explanations, details and tips of all kinds.

Front cover

Along with the STL file of the box, on Thingiverse, I leave you also the front cover in SVG vector format.

I I have cut the front in adhesive vinyl with a cutting plotter.but you can print it out with a normal printer, cut it out by hand and glue it in. or do it laser in another type of material.

I leave you also the front cover the format of Silhouette Studiowhich is the cutting plotter I use.

Forthcoming improvements

In the next version of the box, which I intend to make, I intend to introduce the following improvements:

  • Widen the LED gap to 10mm to be able to install the LEDs. LED strips standard flat shape.
  • Provision of holes for the installation of 5mm round LEDs for those who prefer it (e.g. for normal RGB LEDs).
  • Change the position of the buzzer to leave the front panel clean and allow the installation of the buzzer modules most common.

If you want to suggest any additional improvements, you can leave them in comments.

The idea is not create several versions for different parts (e.g. one for NodeMCU and one for Wemos D1 Mini, whoever wants to put in a Wemos D1 Mini can leave it air-wired) but also make improvements extending functionalities or improving usability.

User boxes

Some users have designed their own boxes and some of them have actually improved my design by a lot!

If you have designed a box, don't be shy, let me know so I can include it.

Here are the boxes designed by users with the links to download them.

Danimod User Box

One box very elegantin my opinion. In the following video you can see it in detail.

You can download it here.

The screws for the cover are M2x7.

Danimod has also designed an optional bracket for your box which, to me in particular, looks phenomenal. You can download it from the same site. Also, as you can see, he has fitted his meter with LEDs that change colour with the CO2 level.

Nacho User Box

Nacho (nacho at pearquitectos.com), en architect expert in healthy and efficient housesand has designed a box with a very interesting design, inspired by Netamo.

You can download the STL from the box from hereso you can print it out.

Contracovid User Box

The user box Contracovidbased on that of Danimod (in fact, you can use the same cover), it is an adaptation to fit the Dupont connectors (so as not to have to weld) and dispensing with the OLED display.

Contracovid user video box

In the following picture you can see the internal distribution of the components.

Photo box from user Contracovid

You can download the STL from the Contracovid box. from hereif you want to print it (you know, use the same cover as the Danimod box).

23 thoughts on “Caja impresa en 3D para CO2 Easy”

  1. Let's see if you see it and I'm lucky and you answer me.

    I can't print in 3d. You talk about using boxes that you buy 10 at a time.

    What are they?

    Thank you very much!

    • I answered this same question in the comments of the article "A home CO2 meter with Wifi against coronavirus". I have put the link to the type of box I use in the same article.

  2. Good afternoon

    I have followed your manual from start to finish and I can not be more happy and satisfied with the result, that said, instead of putting LED strips I want to put a traffic light, as the meter I'm doing is for the nano's school, and I think his teacher will find it easier and more comfortable to distinguish if she does not have it near her, but I don't know how I would have to configure it in the espeasy, I mean I don't know if the Neo pixel device would work for me or if the rules that you have created would be valid for it and I have no idea how the connections would be, I only have clear GND, the other 3 wires I have no idea where to connect them. Thanks for the tutorials, videos and the work you do, it makes it much easier for us who have no idea and we can have the meter, thanks again.

    Best regards

    Best regards

    • Hello.

      I am preparing a post and a video explaining the handling of the WS2812 LEDs in depth, but it will take a few days to be ready. If you want you can wait.

      In any case, the operation is very simple.

      I don't know if you have seen the full video. It's explained there. What is explained in the video is already a traffic light.. The strip lights up green, yellow/orange or red depending on the CO2 level.

      If it is not a traffic light of this type that you want, explain me a little bit your idea, and I'll see if I can give you some brief instructions while I finish the video.

      I'm a bit lost... it's not GND plus four wires, it's three wires in total and in the video you can see it very well (minute 23:25). The schematic shown in the video (and above, in the article) is this:

      WS2812 connection to NodeMCU

      What do you mean, should you put the Neopixel or another one? Which one?
      And "if the rules would be valid for it", for which one?

      As I answer you I realise that I'm very confused, maybe I'm just thick and I haven't understood the question. Tell me what you want and I will try to help you.

      • I want to expand my response because as I read it I get the impression that I seem angry and/or cutting and that is not the case, on the contrary, I am very grateful for your selfless work and the time you dedicate to us as well as the information you provide us with, but I would like to make it clear.

        • No, man, no! Don't worry! 😁 hahahaha

          Now I know what you mean about the traffic light....

          It can be installed, but it is not that simple. You have to put in external components that complicate it.

          The NodeMCU can supply maximum 12mA on each pin. I have searched the internet and this traffic light needs: Red 13mA; Yellow 13mA; Green 25mA.

          Maybe the red and yellow would be seen, but the green would not light up.

          To increase the current you would have to put three transistors and we are already complicating the circuit a lot...

          Here's an alternative idea: Print a cover with the traffic light printed on it for the box and match the holes with the LEDs on the WS2812 strip.

          Another option would be to make a 3D printed traffic light with the WS2812 strip inside.

  3. Hello

    I am very grateful for the time you dedicate to us and the opportunity you give us, I wanted to make that clear, it is clear to me that in a face to face conversation it would not have been necessary but when one writes sometimes ....

    • That said, don't worry at all. 😀

      You didn't come across as serious or curt. My initial response, perhaps it did seem serious or curt, but I was so frustrated at not being able to give you a better response that it came out that way. Surely, as you say, face to face this wouldn't have happened... writing is very cold sometimes...

      Best regards and thank you.

      • Good morning

        With your explanation it is clear to me that the traffic light is completely ruled out and the alternative of printing one for the LED strips seems to me to be a very good solution.

        I'll see how this turns out and let you know what I do.

        Thank you for everything and I am glad we understood each other.

        Best regards

        • Hello.

          I have added to the article instructions on how to make the traffic light at "Adding a ruler to make an LED traffic light".

          I have tried to take pictures, but taking pictures of LEDS is extremely difficult and they come out terrible.

          Best regards.

          • Good afternoon

            I can only thank you and congratulate you for your hard work and generosity, a machine of "cacharreo" and a 10 as a person.

            Best regards

  4. Hello, I am very grateful for your contributions and today I have started to print your box model to house the CO2 sensor, and I would like to finish the project with the lid of the same, but I have no idea how to do it, so I would appreciate if you can provide a model of lid to print that fits this box that you propose, so that I do not have everything in sight. Best regards and keep up the good work!

  5. I have just stumbled upon a gold mine with this site. I'm a teacher and I'm doing a research project for my baccalaureate which is based on the construction of a co2 sensor and doing analysis in different classrooms to see if the ventilation measures are effective. We will look forward to new updates while the components arrive from aliexpress, thank you very much.

    • Hello Aitor.

      I'm glad it will help you with the construction of those CO2 meters, which are so necessary in the classroom.

      I know that there are several teachers, especially VET teachers, who are implementing this project in their classrooms.

  6. Hello, I would like to print Nacho's box but the stl file does not open in the Repetier. Is it possible that the file is damaged? Can it be downloaded from somewhere else or could you send it to me by email?

    Thank you very much and keep it up!

    • Hello.

      Well, I can't tell you. The only one I have is the one he sent me to put on the web.

      I'll send you an email, see if you can send it to me again.

      Best regards.

    • Hi Ricardo.

      The STL I have is the same one available for download in the page.

      I just sent the author an email asking if he can send me again the STL.


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