Fake CO2 monitor (party detector) with schematic

I think you are right about it being a ghost detector, it seems to be quite sensitive to spirits.

Maybe the circuit designer got his sensors all mixed up in a box and thought "the one that reacts when I blow on it must be the CO2 sensor" - too bad he wasn't entirely sober at that time... 😂

"Unless you live in a hermetically sealed building" our office moved to a whole floor in a WeWork a few years back, and it always felt "stuffy" in winter. Towards late morning I was always fatigued and sleepy. I put it down to the coffee. Someone else bought an proper air quality meter and we realised that in winter, the CO2 levels in the 200-person office would rise from 9am through to about 2pm, and the moment they hit 5000ppm they would drop abruptly and hover at a lower level. This pattern repeated every day. It seemed that to save money on heating WeWork had configured the HVAC system to let CO2 rise up to the legal maximum before they let in outside air. Unfortunately, you start feeling drowsy and foggy around 2000ppm. Without the CO2 monitor, we would have blamed the coffee - because it would be crazy to suggest that a company was suffocating the workers to save on the heating bill.

The auto subtitles perfectly spelling "n-i-c-o-t-i-n-e", dashes included, is pure sass.

We have real CO2 sensors in our office building, with LED lights that go from green to yellow at 800 and to red at 1200 ppm. I designed and built them myself (around 150 sensors for the whole company) at the time we had all those mask and quarantine regulations. They contain the Sensirion SCD30 sensor module, which uses NDIR to detect CO2, which is accurate, but also quite expensive. They do help a lot with air quality monitoring, because as you mentioned, humans exhale CO2 at all times, and if too many humans are in one room with bad ventilation, the levels rise quickly. It will never reach dangerous levels in a normal building, but at 1500ppm and above CO2 causes headaches and reduces focus, which is usually a bad thing in work environments. High CO2 levels also mean a lot of exhaled air and therefore higher risk of aerosols (virus transmission), so respiratory infections have declined since we use the sensors and therefore ventilate the rooms when needed.

There's "zp16" written on the board, which is a VOC air quality sensor. The empty place for "infrared module" would be for the actual infrared CO2 sensor.

There are "CO2" sensors available that in the fine print says they are "CO2e" or "eCO2" sensors. Which means that they are VOC sensors, and the VOC level is cleverly and most often incorrectly used to guesstimate a probable CO2 level, assuming human presence. Could that be the case here?

"monochromatic display with coloured panels printed over the circular segments" That's pretty much the description of how Space Invaders machines first went from B&W to colour. A few strips of coloured gel over the screen. Sometimes not much moves on from the 1970s.

I have used NDIR-based CO2 sensors (MH-Z14, MH-Z19) in an office setting, and it was quite interesting to note the average levels. After seeing the PPM levels in a meeting room zip past 2,000 ppm with about a dozen people inside for an hour, it made sense to me that one would start feeling drowsy and lose focus during such meetings. It's not just that they're tedious wastes of precious life minutes. A number of studies have been performed on the impact of CO2 levels on cognitive functions, which show that a rise from ~400 ppm to 800 ppm drastically reduces one's ability to perform even basic office tasks. It's like being sleep-deprived, or tipsy. Beyond 800 ppm it just plummets and by the time you hit 2,000 ppm, individuals will begin to get headaches, start feeling nauseous, etc. At around 5,000 ppm you'll have people literally passing out, with a number likely having puked up their guts before then. In the open plan office of this place levels got to 800 - 1,000, which was a good hint to crack open a window, which helped a lot. In that sense, CO2 sensors are an invaluable tool to keep track of air circulation in a building, and the build-up of stale air. The same project (BMaC: Building Management and Control) also got used for other purposes, such as keeping track of the number of cups of coffee drawn from the machines via their serial port, which provided an interesting comparison point for CO2 levels and coffee consumption :)

We were having weird headaches and just foggy feelings since moving into our new house. Someone mentioned checking CO2 levels since the house is pretty sealed up. Got a sensor and it showed over 3000ppm, we also have all natural gas appliances. After getting it below 800ppm, we can tell a huge difference.

This is why I built my own CO2 meter. I knew exactly what was in it and learned something new while doing it. It also logs the data which you can view on your phone.

CO2 is used as a proxy for measuring air that is stagnant. Mostly in the context of trying to ascertain if a public building has adequate exchange of outside air to help reduce airborne virus spread.

Me thinks that Clive had quite a few "test" glasses of spirits for this video :)

My parents have an air filter/ionizer that automatically ramps up fan speed based on alcohol levels. Hilarious!

Clive, you were wondering why someone would want to measure Co2 content. We use an array of sensors (including Co2) when welding in a tank or bund. Co2 is heavier than air so you end up with the bottom of the tank filled with Co2 and you suffocate. Always good to have something beeping away in the background. Though obviously not this piece of crap.

Wow! I just received a nearly identical unit in the mail last week! Mine’s the fancier version of this one that “detects” formaldehyde, TVOC, PM2.5, PM10, CO and CO2. But mine actually has a GP2Y10 (dust sensor) module in it. I’m doing a soda steam test right now, but from my first test it just detects alcohol. It only has one gas sensor in it, so it’s clearly lying about something. I’ll update this comment with an edit in a few minutes Edit: just put it in a bag of pure CO2 and the CO2 reading is dropping… Edit2: Whoa! Whatever sensor they’re using actually does detect CO2 but registers it as TVOC. Somehow in the bag of CO2, it mins the CO2 reading but maxes the TVOC reading. There’s something fancier going on here. I think the gas sensor is actually sensitive to two types of gases, but the math isn’t working properly. I just breathed 2x beer breath into the CO2 bag, and the CO2 reading started climbing. Man, I wish the gas sensor had a number on it. I think I might have to dremel it open and see if I get any clues.

Co2 sensors are common because Asian countries (at least Japan)started recommending /mandating that all public venues have them at the start of the covid pandemic, in order to show sufficient ventilation in a crowded room. I believe the suggested max level was around 1000. They are still in place everywhere

I worked at Microsoft in a building they rented back in the 1990’s. They changed the cubicles to only 6’x6’. Everyone got headaches after 3pm. Back then it was expensive to test co2 but after months we got them to test it. The level was above 2000ppm. They upgraded the hvac system fresh air and our headaches went away.

I notice the care you take with the utterance of "nic...o...tine" to avoid upsetting the mechanical censors. You could always tell them you were referring to that notorious supervillain from early 80s public service comics, Nick O'Teen.

I once spent almost 2000 dollars on a telaire co2 detector for the routine testing of air conditions in an agricultural facility, quite the unit it was so accurate I couldn’t even breathe while testing lol