CO2 on a giant screen for bars, restaurants, classrooms and the like

Last modified 12 months

There are many people who are looking for a CO2 meter with a large display that can be seen at a distance for installation in hospitality, schools, gyms and the like.

The truth is that the system is so flexible which, as you will see later, not only allows the creation of huge display panels (from 5 ″ mobiles to 7 ″ tablets, 12.9 ″ iPads to 100 ″ Smart TVs), but it is possible to create extremely small screens, like the floating window for teachers I teach below.

During this time I have realized various prototypes and experiments with different types of displays. I have used large seven segment LED displays, matrix panels, addressable panels, etc.

The problem I encountered was, on the one hand, the rigidity of the system (each person has different tastes and needs and it would have been necessary to adapt the system to many different types of hardware) on the other hand the construction difficulty and the cost.

Finally, I said to myselfWhy not take advantage of the fact that the CO2 meter has a complete integrated web server and take advantage of it to display it on all types of screens?

Said and done, I rolled up my sleeves, got to work and today I bring you the result ...

It is not finished yet, but I want you to open your mouth about what is coming.

My knowledge of CSS (I defend myself, but I have not mastered it) makes it go slower than I would like, and it gives me much more work than necessary.

If you have CSS knowledge and want to collaborate, write to me through the Telegram group, please. With a little help we can achieve something very, very attractive and interesting from which many people who need it can benefit.

CO₂ meter on monitor or TV

CO₂ benefits on the big screen

To be based on HTML, CSS, and JavaScript (web technologies)There are many benefits to be gained from this large screen display system.

Aside from the obvious benefit, which is possible view information remotely, we would have the following:

  • Great flexibility content and design
  • No investment. Needless nothing else than the home CO₂ meter of this blog (and the device where you want to view it, of course).
  • Adaptable to all types of devices (Phones, tablets, computers, Smart TV, etc.).
  • Design possibility responsive (self-adaptation to the display device).
  • Multiple simultaneous clients.
  • possibility of integrate other sources of information.
  • Complete freedom to choose colors, sizes, fonts, etc.
  • System completely autonomous (does not need internet connection to work)
  • No library dependencies like jQuery or others.
  • Customizable logo (I take everything) easily.
  • Possibility of defining multiple pages with different layouts.

Large screen CO₂ meter capabilities

Although, at the moment, it is only a prototype (soon I will publish instructions and the necessary files, on this same page, so you can do it too), the display system already has the following functionalities:

  • Display of any parameter CO₂ meter (such as temperature and humidity, in these examples).
  • Real-time display without reloading the page.
  • Display of historical charts (from Thingspeak or others).
  • Color change, according to the CO₂ level (traffic light effect) with user adjustable levels.
  • Possibility of viewing external data.

Of all of them, which will be good for one or other people, I think that the most interesting and useful for everyone is that the display always shows the current CO₂ value. You do not need to reload the page or press any button to have the data of that moment.

Display devices

There are many devices in which the visualization of CO2 is possible. Whether you need a small autonomous system, with a tablet, for example, for medium-sized spaces such as a Large format TV, for large venues, you always have a choice.


The tablet is the quintessential display device.

There are really cheap Android tablets, even older tablets, that you may no longer use, and that you can use for this by giving them a new youth.

They are ideal to put them fixed on the wall with some kind of support, like this:

Dockem Koala Mount Tablet Wall Mount: No-Damage Universal Wall Station for iPads, iPad Airs, Pro, 9.7, Galaxy Tab / Note and Other Tablets (Black version)
  • DAMAGE FREE INSTALLATION AND REMOVAL: Installs in less than 2 minutes using 3M Damage Free Command Strips (included) that are rated to hold up to 2.25kg each; no need for screws or holes; designed for use on flat, smooth surfaces (screw-in versions, Koala Mount with screws and Koala Mount 2.0 sold separately)
  • UNIVERSAL: Uses 2 separate brackets that can be set to any distance required by your device, allowing full width compatibility. This includes iPads 1, 2, 3, 4 and the New iPad 9.7, Pro, Air, Air 2, most Samsung tablets, and many more. The brackets will fit any device 11mm thick or less. It can be used with protective covers as long as its thickness is less than 11mm.
  • SIMPLE: Super easy donning and doffing, can be set to portrait or landscape mode. No need for extra accessories; no special covers or add-ons are required on your tablet. Full access to ports / buttons on devices larger than 7-8 '' may work better with our Koala Mount 2.0. Pre-installed cable clips to help keep your cable tidy.
  • MOUNTING: Comes with 3M Regular Command Strips that are not designed to function in areas exposed to high temperatures or humidity (such as the bathroom). For this, 3M manufactures special water and heat resistant strips. Also, Command Strips tend not to work well on textured surfaces and some papers. We highly recommend taking our Endurance Test. Command Strips are not reusable after being removed.
  • NOTE ON COMPATIBILITY: While it fits most popular tablets, the mounts can lock ports / buttons on both sides between 3.8cm and 9.5cm from the bottom (7-8 '' tablets like the iPad Mini may have ports blocked in landscape mode - if this is your case you can see our Koala Mount 2.0).

Smart tv

Most of the Smart TV of recent years support HTML, CSS and JavaScript (internet technologies) so it will be very easy to use them as a CO₂ display device.

This is a perfect solution for really big rooms in which we need the information to be seen from all points.

We can put a SmartTV of 4K and 58 ″, for relatively little money that it will be seen from far away.

Normal TVs (with the help of, for example, an Amazon Fire TV Stick)

If you have a slightly old television, or any monitor with HDMI input, you can use it to display CO₂ levels using, for example, a Fire TV Stick:

Fire TV Stick Lite with Alexa voice control | Lite (without TV controls), HD streaming
  • Our most affordable Fire TV Stick: fast streaming and Full HD quality. Comes with the Alexa voice control | Lite.
  • Press the button and ask Alexa: use your voice to search for content and start playback in multiple apps.
  • Thousands of apps, Alexa skills, and channels, including Netflix, YouTube, Prime Video, Disney +, DAZN, Atresplayer, Mitele, and more. Subscription charges may apply.
  • Amazon Prime members have unlimited access to thousands of movies and series episodes.
  • Live TV: Watch live TV shows, news and sports with subscriptions to DAZN, Atresplayer, Movistar + and more.

Teams of teacher, monitor, supervisor, etc.

Not everything is giant screens. Sometimes the essence comes in a small bottle.

Sometimes it is important that the teacher, monitor, supervisor, etc. have a chance to see permanently the CO₂ level in the environment.

In this picture (Bottom right) you can see as a small window "fleet" on the teacher's computer above what he is doing, allowing you to view the CO₂ level at all times. The teacher can drag the window to move it around, resize it and of course, hide it.


As with everything, this system also has its limitations.

These are the ones I know so far (if you discover another, let me know to include it).

  • Low security: Not valid if you want to show "sensitive" data. It is intended for public data, so you do not care if someone, in any way, connects and gets it.
  • Concurrent users: The microcontroller used in the CO₂ meter (ESP8266) is not a real web server, so it will not support many connections at the same time. I have tried it with four simultaneous connections and it works, but I don't know how many it would last. This is intended to connect a few display devices, not a lot of people to connect to the CO₂ meter directly.

Display examples

I will leave you here some examples of what I'm doing, to give you the idea:

Recommended tablets

Almost any tablet should do as a display device. Logically there are so many models that it is difficult to know a priori if any of them will not work for some reason.

Most importantly, when used as a display device is that the tablet is able to be turned on and charge simultaneously. Almost all do, but not all, I, for example, I have one that, even though it's plugged in, consumes more than it charges, so after a few hours it turns off.

I recommend that you buy your tablet on Amazon, where you can return it and exchange it for another if it does not work, without any problem.

Here are some of the best-selling tablets from Amazon:

Bestseller No. 1
TECLAST M40 Pro Tablet Android 12 8GB RAM+128GB ROM 10.1 Inch, 4G LTE, 5G WiFi, (1TB TF), Octa Core 2.0GHz, 7000mAh/SIM+TF/BT5.0/Face ID/FHD1920*1200/Dual Cameras/GPS/OTG/Type C/4 Speaker/Metal
  • CPU - Tablet is with UNISOC T616 Octa Core processor is a highly integrated SoC platform with a maximum frequency of 2.0GHz, AnTuTu of about 200,000 points. It supports TD-LTE, FDD-LTE, TD-SCDMA, WCDMA and GSM modes. The MAIN ARM Cortex-A75 application processor has better intelligent AI acceleration and runs more smoothly.
  • 10.1"2.5D OGS 2.5D SCREEN + ULTRA THIN DESIGN - 10.1 inch 1920 x 1200 Full HD IPS narrow bezel display tablet can effectively suppress the visual protection of blue light. Fully laminated 2.5D touch screen, 10-point inductive touch control, with the same back-mount technology as iPad, it is very easy to hold and the structure is more durable and slim.
  • HIGH SPEED DUAL 4G INTERCONNECTION+8GB RAM+128GB ROM - The system interface is very simple and fast to operate. Intelligent AI optimization speeds up system operation and improves app launching and switching. It can easily process movies, images, videos, music and more. Equipped with 7000mAh battery, it ensures high-efficiency tablet operation for a long time. With default brightness, it can watch up to 7-8 hours of 1080P movies.
  • LTE 4G + 2.4GHz / 5.0GHz WiFi + Bluetooth 5.0 - Hidden SIM / TF card slot design, more support VoLTE and carrier aggregation, simultaneous implementation of calls and Internet, Beidou, GPS and other high-performance satellite navigation networks high speed, 802.11 AC dual band high speed WiFi and Bluetooth 5.0 wireless transmission. Connect to the internet and access the web from anywhere
  • 8MP REAR CAMERA + 5MP FRONT + INDEPENDENT ACOUSTIC CAVITY - Momentum sound quality and intelligent independent amplifier chip brings immersive experience and relaxation. Equipped with dual cameras, the M40 Pro can make video conversations anytime, anywhere and record every moment you move.
Bestseller No. 2
BRILLAR Android 12 Tablet 10 Inch, WiFi Tablet PC | Octa-Core | 6+128 GB | 8 + 13MP Camera | 6000mAh Battery (Gray)
  • 【Complete Android 12】Brilliant installed the full version of Android 12 system instead of Android Go version. In this version, you can enjoy a more complete Google service, prestalado applications such as Netflix, Disney +, Tiktok, Roblox and YouTube.
  • 【8 Cores, 6 + 128 GB】The Brillar T16 tablet tablet is equipped with a 2.0 GHz 8 Cores chip, allowing you to run smooth execution of various games, videos and work applications. The 6 GB RAM allows you to multitask at the same time. 128 GB RAM, don't worry about lack of memory, it also supports extended storage space with up to 256 GB.
  • 【6000mah Battery】Play video and Games for about 5 hours, Play Music for 10 hours, Read for 12 hours. It will be your best friend on the journey.
  • 【WiFi 5G]】The tablet to SHINE T16 supports 5G WiFi, so you can enjoy online fun faster without worrying about games or video cards.
  • 【10.1 inch touch screen】1280 * 800 resolution, 2.5 D G+G display.
SaleBestseller No. 3
Lenovo Tab M10 Plus (3rd Gen) - 10.61" 2K Tablet (MediaTek Helio G80, 4GB RAM, 64GB expandable up to 1TB, 4 Speakers, WiFi + Bluetooth, Android 12) - Dark Grey
  • 26.92 cm (10.6") 2K IPS touchscreen, 2000x1200 pixels, 400nits; Streams Netflix, Disney and other services in up to 1080p, the highest video resolution available for mobile devices. Compatible with Lenovo Precision Pen 2 (not included).
  • MediaTek Helio G80 Octa-Core processor with a main frequency of up to 2.0 Ghz
  • 4GB Soldered LPDDR4x RAM, expandable via micro SD card up to 1TB; allows multitasking without any problem
  • 64GB storage (eMCP, eMMC 5.1) expandable via micro SD card up to 1TB
  • Integrated ARM Mali-G52 MC2 GPU Integrated graphics card ARM Mali-G52 MC2 GPU
SaleBestseller No. 4
TECLAST Tablet 10.1 Inch Android 12 P30S, 5G WiFi, 4GB RAM+64GB ROM, 2.0GHz/1TB Expandable/Bluetooth 5.0/GPS/Dual Cameras/SD/Octa Core/Type C/OTG/Face ID/Metal
  • 10 Inch Tablet:Tablet 10.1 inch has 1280×800 HD IPS display and adopts T-Color color enhancement algorithm, which not only provides high quality image details, but also enhances the color effect of the image and finally forms the best image. At the same time, the tablet screen adopts 2.5D touch screen and metal body with curved edges, which has excellent feel and beautiful design.
  • Android 12 Tablet and Metal Body:Tablet equipped MTK8186 with eight-core A55 CPU processor, the highest frequency is 2.0GHz, fast performance. And equipped with Android 12 intelligent operating system, plus more intelligent Ai optimization experience, new features such as new gesture touch mode, global dark mode, etc. make your tablet use more personalized experience.
  • Tablet 4GB RAM 64GB ROM: Tablet 4GB running speed, 64GB storage space. You can watch movies, take photos, record videos, listen to music, etc. easily through your tablet. In addition, the tablet supports 1TB TF card to expand the storage capacity. Satisfy your daily needs for work and study. warning! Not suitable for large games.
  • WiFi 5.0: tablet with dual band AC high-speed WiFi and Bluetooth 5.0 wireless transmission; supports Beidou, GPS and other traditional satellite navigation systems, allowing you to quickly reach your destination.
  • Full-Fit 2.5D:Tablet Full-Fit 2.5D Display Wide and elegant sound cavity unit and metal body, bright treble and strong penetration, deep bass. 5MP rear camera plus 2MP front camera, whether recording spectacular scenery, daily business documents or video conference, provides a great user experience.If you encounter a problem with a product, please contact us through your order and we will help you solve it.
SaleBestseller No. 5
JUMPER Tablet Android 12, 10.1 Inch, 6GB DDR4 128GB ROM, Octa Core, 6000mAh, 4G LTE, 5G WiFi, Type-C, SIM/TF, IPS FHD 1920x1200, 13MP+5MP Cameras, Bluetooth 5.0
  • 6GB RAM + 128GB EMMC: The tablet laptop is equipped with 6GB RAM and 128GB large-capacity memory. You can expand the memory up to 256GB, which will help you store everything you want, such as photos, music, movies and apps.
  • Android 12 and 6000 mAh: The tablet PC is equipped with Android 12 operating system with GSM certification, which makes it stable, smooth and fast. With a huge 6000 mAh capacity battery, it supports daily use for 6-7 hours after charging. You can take it anywhere without worrying about the battery.
  • Powerful octa-core processor: The tablet PC is equipped with a powerful octa-core A55 processor with low power consumption and an advanced GPU. It offers fast multitasking for videos, movies, games and more.
  • 1920 x 1200/10.1 inch IPS: The tablet has a large 10.1 inch touch screen with 1920 x 1200 HD resolution, can offer you a wonderful and smooth experience when playing games and watching movies. Equipped with 13MP rear cameras and 5MP front cameras to help you capture memorable and beautiful moments.
  • 4G LTE/ 5G WiFi + GPS: The tablet is equipped with high-speed dual-band WiFi which provides more stable internet. Support 4G calling, you can surf the internet during the call. When there is no WLAN, you can always surf the internet by inserting a SIM card. It supports the four major navigation systems, such as GPS, providing you with the most accurate positioning and guidance wherever you are.

If you use any tablet that is sold on Amazon (whether it is included in this list or not) tell me, with the results obtained, to be able to advise users.

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6 thoughts on “El CO2 en pantalla gigante para bares, restaurantes, aulas y similares”

  1. Hello, how is this project going? I would like to be able to test it for my place.
    It seems to me that they are going to make it mandatory.
    I have asked the pieces to go assembling it. I'll give you the ember with my problems 🙂

    A greeting.

  2. Hello! Please can you publish at least the basics to be able to view the data on a tablet? Even if it's just the real-time value! Thank you very much for the work !! All the best

    • Hi Jordi.

      We are just picking it up, with the help of comrade Sey. Let's see if we can give it a good push and can publish it shortly.

      A greeting.

  3. Hello,

    Lately I follow your blog day by day. I am a teacher and I am about to start the CO2 meter project, with students. From what you see in an image, it seems that you use Thingspeak to publish the sensor readings, I have tried but I have not been able to achieve it, I just discovered ESPeasy and I still do not understand the platform, nor MQTT. However, with Arduinoblocks I have had no problems. Could you tell me a tutorial to connect to Thingspeak? I don't think I have a problem if it's in English.
    I have also observed in the video about MH-Z19B that there doesn't seem to be much difference between the results of the original MH-Z19B and the reference Senseair, right?
    Greetings, and thank you very much for all the work you do and show us.
    Thank you


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