I must admit that I love today’s incredibly small sensors, especially ones I can use in conjunction with my iPhone. When the COVID19 pandemic was in full swing at the beginning of 2021, for example, I picked up a nifty little contactless thermometer, which I now carry around with me in my backpack (see Super-Duper Smartphone Thermometer).
A couple of days ago, my chums at Infineon were kind enough to send me a CO2GO device, which was created by one of their partners. This bodacious beauty is a mobile CO2 (Carbon Dioxide) sensor that you can carry in your pocket and that you can use to quickly and easily test the quality of the air you are breathing.

Even when I was a kid, I remember wondering about the possibility of running out of oxygen when my bedroom door was closed at night. This may not be something you’ve thought about before, but CO2 is an odorless and colorless gas that we exhale with every breath. The problem is that humans cannot detect elevated CO2 levels in the air by themselves, which is why we need sensors to do the job for us.
While CO2 is not harmful at normal quantities, high levels of the gas can replace oxygen in the blood and impact how well we feel and how well we think. According to the CO2GO website, the CO2 levels commonly found in offices and meeting rooms may cause people to feel tired and indecisive or suffer from a loss of concentration. Higher CO2 levels can cause dizziness and headaches, and that’s just the start of your problems.
The reason the guys and gals at Infineon are so happy about CO2GO is that it boasts one of their XENSIV sensors, which are used to sense the world in automotive, industrial, and commercial markets. In the case of the CO2GO, we are talking about one of Infineon’s disruptive high-performance C02 sensors, which are based on photoacoustic spectroscopy (PAS).
To be honest, this technology was a new one on me, but I had a quick Google while no one was looking, ending up at the Wikipedia, which informs me that, “Photoacoustic spectroscopy is the measurement of the effect of absorbed electromagnetic energy (particularly of light) on matter by means of acoustic detection.” Wow! Who would have thunk?
Reading on, we discover that, “A photoacoustic spectrum of a sample can be recorded by measuring the sound at different wavelengths of the light. This spectrum can be used to identify the absorbing components of the sample. The photoacoustic effect can be used to study solids, liquids, and gases.”
One thing that really blew my socks off (metaphorically speaking) was when I read that, “The discovery of the photoacoustic effect dates to 1880 when Alexander Graham Bell showed that thin discs emitted sound when exposed to a beam of sunlight that was rapidly interrupted with a rotating slotted disk.” Give me strength! Is there anything the ancients didn’t discover?
Even without an associated app, you can power your CO2GO by connecting it to a USB port, in which case LEDs behind a small window display Green (<500 to 800 ppm = no health risks), Yellow (801 to 1600 ppm = moderate health risks), or Red (1601 to 5000> ppm = serious health risks).

More detailed and finer-grained data can be obtained using the apps that are available for PCs and smartphones (the website shows downloads only for the PC Desktop App and for the iPhone, so I’m not sure about Androids).
The screenshot presented here is from the Desktop App running on the PC in my office. The graphical portion of this image commences around 5:27 p.m. yesterday evening, which is when I plugged my CO2GO in just before heading home. As we see, at this start time, the CO2 in my office was around 700 ppm, which is OK but not great. The CO2 gradually fell overnight, but it quickly ramped up when I entered my office at 9:00 a.m. this morning, after which it remained hovering around the 700 ppm mark, apart from a taking a dive around 12:00 noon when I popped out for lunch with my friend Bob (pronounced the usual way with a silent ‘Q’). Based on these results, I’m going to start leaving the door to my office open and use a fan to bring some fresher air in.
Chatting with my friends at Infineon, I’m delighted to discover that they are planning on adding other harmful gases in their next generation devices. They haven’t confirmed which gases, but CO (carbon monoxide) is definitely a strong contender. It may even be possible to detect multiple gasses with a single sensor, although no one is making any promises at this time.
Personally, I think it won’t be too long before all of these sensors are embedded in our smartphones, thereby allowing everyone to be informed if there are any problems with the air they are breathing. Meanwhile, I am very happy having my CO2GO monitoring the air here in my office. How about you? Could you be tempted to splash the cash for one of these little scamps?
In one of those cosmic coincidences, on the same day that I read your blog I found and article in the local paper about being able to loan a CO2 monitor from the public library in Peterborough (about 130km from Toronto).
The idea is to mitigate the spread of Covid by monitoring the ventilation of the room you are in. Poor ventilation = higher CO2= higher risk of Covid transmission. Of course this is a generalization. As the article points out, a room with poor ventilation, but with a hepa filter has a lower risk.
The Toronto library is investigating implementing a similar program.
https://www.thestar.com/news/gta/2022/04/03/peterborough-started-a-co2-monitor-lending-program-and-toronto-may-soon-follow.html
It’s very small and neat. But I’d still be tempted to build my own rather. you can get sensors for CO2, CO, VOCs and, I think, particulate matter, and others. The problem comes in accurate calibration, especially for the stuff that you can’t easily get an accurate comparison reading for. CO2 is easy, it’s usually a bit over 400 PPM (Thanks to mankind’s addiction to fossil fuels) and I think you can find the levels published somewhere. But the others you really only need an indication that they’re a bit above normal, for example CO in boat engine spaces.
But getting one of these would save a lot of time. However, following your link I find they are 120 Euros, and you could build a lot of stuff yourself for that!
Take a look at this beauty I got at Crazy Cazboy’s for 25 cents.
No- It does not have computer connectivity, but for the price I’m OK with that.
FYI- They don’t have a Cazboy’s in Huntsville yet, but there is one nearby in Guntersville. Go on Thursday. That’s when everything is deeply discounted and the only things left are the things that other people couldn’t figure out what they are.
Hi Rick — I don’t know why your image got chopped out, but here it is:
25 Cents!!!!!! OMG I don;t have any time free at the moment, but if you see any more of these, snap them all up!!! I would LOVE one of these!!!