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

There are many people who are looking for a CO2 meter with large display that can be seen from a distance for installation on catering, schools, gymnasiums and the like.

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

During this time I have carried out 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 was facing was, on the one hand, the rigidity (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 use it for display on all types of screens??

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

It's not finished yet, but I want to give you a taste of what's to come.

My knowledge of CSS (I know my way around it, but I haven't mastered it) makes it go slower than I would like, and gives me a lot more work than necessary.

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

CO₂ Meter on monitor or TV

Benefits of CO₂ on the big screen

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

Apart from the obvious benefit, which is possible viewing information remotelywe would have the following:

  • Great flexibility content and design
  • No investment. There is no need to no more than the homemade CO₂ meter on this blog (and the device where you want to display it, of course).
  • Adaptable to all types of devices (Phones, tablets, computers, Smart TV, etc.).
  • Possibility of design responsive (self-adaptation to the display device).
  • Multiple simultaneous clients.
  • Possibility of integrating other sources of information.
  • Complete freedom of choice colours, sizes, fontsetc.
  • System fully autonomous (no internet connection required)
  • No library dependencies such as jQuery or others.
  • Customisable logo (I take everything) easily.
  • Possibility to define several pages with different layouts.

Possibilities of the CO₂ meter on large display

Although, for the time being, it is only a prototype (I will soon publish instructions and the necessary filesOn this page, so that you can do the same), the visualisation system already has the following functionalities:

  • Display of any parameter emissions from the CO₂ meter (such as temperature and humidity, in these examples).
  • Real-time visualisation without reloading the page.
  • Display of historical graphs (from Thingspeak or others).
  • Colour changeaccording to the level of CO₂ (traffic light effect) with user adjustable levels.
  • Possibility of displaying external data.

Of all of them, which will be useful to one person or another, I think that the most interesting and useful for everyone is that the display always shows the current CO₂ value. You don't need to reload the page or press any buttons to get the current data.

Display devices

There are many devices on which CO2 visualisation is possible. Whether you need a small stand-alone system, with a tablet, for example, for medium-sized spaces such as a Large format TV, for large venuesyou always have a choice.


The tablet is the display device par excellence.

There are really cheap Android tablets, even older tablets, that you may not use anymore, that you can use for this, giving them a new youth.

They are ideal to put them on fixed to the wall with some kind of bracketlike this one:

Dockem Koala Mount Tablet Wall Mount: Damage-Free 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 damage-free 3M Command Adhesive Strips (included) that are rated to hold up to 2.25 kg each; no screws or holes required; designed for use on flat, smooth surfaces (screw-on versions, Koala Mount with screws and Koala Mount 2.0, sold separately).
  • UNIVERSAL: Uses 2 separate mounts that can be configured 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 mounts will fit any device 11mm thick or less. Can be used with protective cases as long as they are less than 11mm thick.
  • SIMPLE: Super easy to attach and remove, can be set to portrait or landscape mode. No extra accessories needed; no special cases or additions to your tablet. Full access to ports/buttons on devices larger than 7-8'' can work best with our Koala Mount 2.0. Pre-installed cable clips to help keep your cable tidy.
  • MOUNTING: They come with 3M Regular Command strips that are not designed to work in areas exposed to high temperatures or humidity (such as the bathroom). For this, 3M manufactures special strips that are water and heat resistant. In addition, Command strips do not tend to work well on textured surfaces and some papers. We highly recommend our Resistance Test. Command strips are not reusable after they have been removed.
  • COMPATIBILITY NOTE: 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 such as the iPad Mini can have ports locked in landscape mode - if this is the case see our Koala Mount 2.0).

Smart TV

Most Smart TVs in 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 where we need information to be seen from all points.

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

No products found.

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

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

Fire TV Stick Lite with Alexa Voice Command Lite (no TV controls), HD streaming
  • Our most affordable Fire TV Stick: fast streaming playback in Full HD quality. Comes with Alexa Voice Remote 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.

It's not all giant screens. Sometimes the essence comes in a small bottle.

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

In this image (bottom right) you can see how a small window "floats" on the teacher's computer over and above what he or she is doingallowing you to view the CO₂ level at all times. The teacher can drag the window to relocate it, resize it and, of course, hide it.


As with everything else, this system also has its limitations.

These are the ones I know of so far (if you discover another one let me know so I can include it).

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

Examples of visualisation

I will leave you here some examples of what I am doingto give you an idea:

Recommended Tablets

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

Most importantly, when used as a display device is the tablet is capable of being on and charging simultaneously. Almost all of them do, but not all, I, for example, have one that, even if it is plugged inThe battery consumes more than it charges, so after a few hours it shuts down.

I recommend that you buy your tablet from Amazon, where you will be able to return it and exchange it for another one if it does not work, without any problem.

Here are some of Amazon's best-selling tablets:

SaleBestseller No. 1
Oangcc 2023 Tablet 10 Inch Android 13 OS Tablet, 12 GB RAM+128 GB ROM(TF 1TB), 5G+2.4G WiFi, 8 Core 2.0 GHz, BT 5.0, Widget, 6000 mAh, 5+8MP, GMS Certified Tablet with Keyboard + Case - Blue
  • 🎄🎁【2023 Android 13 OS Upgraded】: A15 Tablet is powered by the advanced Android 13 OS, which has been fully upgraded in terms of system operation, allowing the tablet to launch applications as fast as lightning, with a greater focus on user privacy and security. it is also Google GMS certified, allowing you to experience stable and smooth Google services.
  • 🎄🎁【5G/2.4G WiFi & GPS Function】: 10.1 inch tablet supports 5G and 2.4G high-speed WiFi, 5G band is faster and improves the stability of network connection; tablet computers can get location information through GPS and Google Maps to provide accurate positioning services anytime and anywhere. 📌PS: If you need to use GPS navigation without network connection, please download the offline map in advance.
  • 🎄🎁【12GB RAM+128GB ROM & CPU 8 Core】: the tablet has 12GB(6+6) RAM+128GB ROM high capacity memory, which can be expanded to 512GB/1TB storage space using SD card (sold separately), enough storage space allows you to store more photos, videos and music; equipped with fast response octa-core processor with 2.0GHz CPU which ensures smooth and stable system performance.
  • 🎄🎁【2-in-1 Portable Tablet 】: Oangcc Android 13 Tablet features a professional 2-in-1 work mode with bluetooth keyboard, mouse and a foldable case that is very easy to set up and connect, and can be easily switched between tablet and computer modes; this versatile tablet solves the problem of those who need to be more productive on the go, and is a perfect gift for family and friends during the holiday season.
  • 🎄🎁【Big Battery and Dual Cameras】. The tablet has a built-in 6000mAh battery, the combination of a high capacity battery and an optimized tablet ensures a longer battery life; Dual HD cameras (Front 5MP + Rear 8MP) to meet all your photography and video recording needs; The tablet weighs about 470 grams, making it easy to carry with you at all times, suitable for long-distance commuting and travel.
Bestseller No. 2
Lville Tablet 10 Inch (2023 Edition), Android 13 Octa Core Tablet, 5G/4G WiFi, Bluetooth 5.0, 8GB RAM+128GB ROM(1TB TF), 5000mAh, 5MP+8MP, IPS 1280 * 800(Black)
  • 【The Ultimate Android Tablet 13】:Android 13 introduced the material you design language, which offers a more user-friendly user interface and enhanced customisation options. It combines wallpaper-based palette control and more intuitive animation. Android 13 also emphasizes privacy and security by designing enhanced app permissions, providing users with complete management control.
  • 【Upgrade 2023 8GB + 128GB + 1TB Scalable】: In addition to supporting 4GB of memory, the 10-inch tablets also support 4GB of virtual memory. With 128GB built-in storage space and up to 1tb microsd cards. 8gb ram revision: system - [memory extension] 4096GB + 4096GB. With 5000mAh battery, you can get a smooth and perfect experience even if you watch videos, surf the internet and listen to music.
  • 【High Performance 8-Core CPU】:Our Android tablet uses a comfortable 10-inch IPS screen LCD for movie watching, 1280 * 800 ultra-high resolution, 7mm ultra-narrow edge, the same size and wide view. The A55 architecture peak performance core up to 2.0 GHz is equipped with eight high-performance cores, enabling low power consumption and low fever in a low-power 22nm process.
  • 【WiFi 6 + Bluetooth 5.0】: The 10 inch tablet uses the sixth generation WiFi technology. Built-in dual-frequency WiFi chip, 5G wifi and 2.4G WiFi are more stable. The latest Bluetooth 5.0 connection supports all your favorite accessories. The 10-inch tablets improve data transmission speed, network capacity and network latency, and have features such as digital health and parental control.
  • 【Ideal For Daily Use】: We offer a one-year warranty for Android 13 tablets.If there is any defect in the product, Please contact us through your amazon purchase record, and we will strive to ensure customer satisfaction. Best gifts for Christmas, Valentine's Day and birthdays.
Bestseller No. 3
FACETEL Tablet 10 Inch Android 13 Tablet Octa-Core 2.0 GHz, 12GB RAM + 128GB ROM (1TB TF) | 5G WiFi | Bluetooth 5.0 | 5MP+8MP Camera | 1280 * 800 | Tablet with Keyboard and Mouse, Case - Rose Gold
  • 【 Android 13 & Octa-Core 】Tablet uses the most advanced Android 13 operating system and 2.0 GHZ octa-core MTK processor to ensure it downloads required apps faster and provides super smooth video playback speed and gaming experience. The latest operating system can also automatically clean and filter junk and unwanted ads.
  • 【 5G Wi-Fi and 12GB(6+6)RAM+128GB ROM / TF 1TB 】Tablet 10 Inch supports 5G and 2.4G Wi-Fi frequency band connection. 5G WiFi is suitable for all home networks and can connect to all networks at will. 12GB RAM (6GB RAM + 6GB RAM expansion) and 128GB ROM, memory can be expanded to 4-1TB, large capacity to meet daily work and learning needs, such as YouTube, Netflix, Whatsapp, Facebook, Instagram, Glovo, Fever, Etc.
  • 【 6000mAh & HD Display 】Tablets have a built-in 6000 mAh battery. Once the tablet is fully charged, the battery life can reach 6-8 hours. It supports 5G Wi-Fi, Bluetooth file transfer. The tablet uses a 2.5D HD IPS display with a resolution of 1280 × 800. The 5 MP front and 8 MP rear HD cameras make it easy to record wonderful moments. Note: The Q6 Tablet does not support SIM card.
  • 【 Tablet Accessories & Best Gift 】Tablet Android 13 are equipped with 1 keyboard, 1 Mouse,1 leather case, 1 protective film,1 charging head, 1 c-type data cable, 1 OTG Adapters. The tablet is paired with a keyboard and mouse to instantly transform into a portable mini-computer. This tablet is high quality and affordable, making it the best Christmas gift for family and friends.
  • 【 Lifetime Product Warranty Service 【【 Lifetime Product Warranty Service 】【【. FACETEL has a professional support team with 10 years of experience. If you have problems with the product you purchase or need an English keyboard, please contact us by Amazon email as soon as possible. After receiving the email from amazon, we will respond quickly, provide technical support and answer questions, and provide a lifetime warranty.
SaleBestseller No. 4
Samsung Galaxy Tab A8 - 10.5" Tablet (4GB RAM, 64GB Storage, Wifi, Android 12) Grey - English version
  • From epic movies to tutorial content to pass the time in style, the Galaxy Tab A8 invites you into a wider world with its larger and improved field of view.
  • Built for an immersive experience, the Galaxy Tab A8 opens up an immersive universe of content, games and activities for even the youngest users.
  • With the eight-core processor paired with up to 4GB of RAM and up to 64GB of internal storage, the Galaxy Tab A8 comes ready to take on any challenge without slowing down or draining the battery.
  • With Samsung TV Plus, you get free, instant TV anytime, anywhere. Enjoy thousands of hours of news, sports, movies, and a variety of other content.
  • Enjoy immersive sound thanks to quad speakers with Dolby Atmos technology.
Bestseller No. 5
YESTEL Android 13 Tablet 10 Inch with 12 GB RAM 128 GB ROM (1TB TF), 2 in 1 Tablet with 5G+2.4 WiFi 2.0 GHz, Bluetooth 5.0, 6000 mAh Battery, 5 MP + 8 MP - Includes Keyboard, Mouse, Case, Black
  • 【Android 13 Tablet】This 10 inch tablet is equipped with the latest Android 13 system, which fully enhances personal privacy protection. The tablet also supports the customization of application icons and the addition of desktop widgets to beautify the desktop theme and manage application information efficiently and can easily manage widgets such as weather, calendar, pictures.
  • 【High Performance 12GB RAM 128GB ROM Tablet】This 10-inch tablet has a processing speed of up to 2.0 Ghz.Equipped with 12GB RAM (6GB+6GB) and 128GB ROM, expandable up to 1TB, it powerfully increases the running speed and storage space for smoother program applications, and also stores all your favorite videos, photos, games and more.
  • 【Tablet with 5G WiFi】This affordable 10-inch tablet supports 5.0Ghz and 2.4Ghz dual-band high-speed WiFi, which makes the tablet's WiFi connection fast and provides good signal through walls. Supports Bluetooth 5.0 wireless transmission. With Android 13 app, let your tablet transfer files and audio stably and quickly.
  • 【6000 mAh battery + 10 inch LCD screen】. Super long battery life is inseparable from the large 6000 mAh battery of the T13 tablet. The 10-inch tablet features a 1280 x 800 pixel LCD display with low power consumption and vibrant colours. This means you can enjoy hours of audio and video entertainment, read on the tablet and make video calls - perfect for travelling or camping.
  • 【Tablet 2 in 1】Tablet set with bluetooth keyboard, mouse, OTG adapter, case, charger, portable screen protector, no need to spend extra money on other accessories, suitable for daily life entertainment and work occasions.Tablet with keyboard Warranty 2 years, if you need our help, please contact us for technical support or return service.

If you use any tablet sold on Amazon (whether it is included in this list or not) let me know, with the results obtained, so that I can advise users.

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

  1. 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 I can 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 do it, I have just discovered ESPeasy and I still do not understand the platform well, nor MQTT. However, with Arduinoblocks I haven't had any problems. Could you point me to a tutorial to connect to Thingspeak? I don't think I'll have problems if it's in English.
    I also noticed in the MH-Z19B video 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

  2. Hi, can you please post 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! Best regards

    • Hello Jordi.

      We are just taking it up again, with the help of our colleague Sey. Let's see if we can give it a good push and publish it soon.

      Best regards.

  3. Hi, how is this project going. I would like to try it out for my premises.
    It seems to me that they are going to make it compulsory.
    I've ordered the parts to start assembling it. I'll keep you posted with my problems 🙂

    Best regards.


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