Compact Sensor Keeps You Safe By Watching CO2 Levels

SYPHCOM, the compact CO2 sensor

Remember when work meetings were just a bunch of people filling up a small, poorly ventilated room with their exhaled breath? Back in the good old days, all you had to worry about was being lulled to sleep by a combination of the endless slide deck and the accumulation of carbon dioxide. Now? Well, the stakes may just be a little bit higher.

In either situation, knowing the CO2 level in a room could be a handy data point, which is where a portable CO2 sensor like this one could be useful. Or at least that’s [KaRMaN]’s justification for SYPHCOM, the “simple yet powerful handheld carbon dioxide meter.” The guts of the sensor are pretty much what you’d expect — an Arduino Pro Micro, a SenseAir S8 CO2 sensor board, and the necessary battery and charging circuits. But the build does break the mold in a couple of interesting places. One is in the choice of display — a 1980s-era LED matrix display. The HDSP2000 looks like it belongs in a nice bench meter, and is surprisingly legible without a filter. It looks like it flickers a bit in the video below, but chances are that’s just a camera artifact.

The other nice part of this build is the obvious care [KaRMaN] put into making it as small as possible. The layout of boards and components is very clever, making this a solid, compact package, even without an enclosure. We’ve seen CO2 sensors with more features, but for a quick check on air quality, SYPHCOM looks like a great tool.

Thanks to [Encarna Navarro] for the tip.

21 thoughts on “Compact Sensor Keeps You Safe By Watching CO2 Levels

  1. Thing most likely confused for a bomb by the TSA, I love it as a bit of ridiculously compact engineering.

    Also has anyone done their own air quality monitoring on a an aircraft. I am rather curious now. Though don’t use this thing

      1. I once travelled to the UK for an international power electronics competition and we had to take turns carrying a duffel bag with a 1kW bidirectional converter we built. It was kinda like hot potato who would get stuck with it by the time we reached the tsa lol. They were a bit confused about it at first but we explained and they were interested in what it was and wished us good luck.

        1. Indeed, international travel with prototypes can be time consuming, so you just need to plan accordingly. But the TSA and their equivalents in other countries are usually very helpful and sometimes very curious.

      2. Well, I’m glad that you got lucky.

        Where might I go to see the first RepRap? All our home and hackerspace 3d printers pretty much exist because of the RepRap project. Surely the first one is in a museum somewhere by now right? It’s an important piece of history.

        Oh, wait. No it’s not. It’s not because it no longer exists. It doesn’t exist because some awful TSA agent destroyed it. Apparently he thought it was possible for a mass of mostly threaded-rod to be an explosive.

        So.. not just FUD.

  2. It’s only got 4 digits so max count 9999 which, as far as I am aware, is perfectly ‘liveable’ for anyone. Stuffy…. yeah, sure, but not dangerous per se. Values of 5,000 for an 8-hour period are ‘commercially’ acceptable and even 30,000 for a 10-minute period is allowed.
    If it had an output to automatically open a window though……

    1. The sensors manufacturer states in it’s datasheet that it’s nice working ranges are 400~2000, but works up to 10000.

      Anyways, tht main purpose of the device is not to measure dangerous levels of CO2 but to provide a way to measure when there’s a need to ventilate closed spaces to prevent high viral charge in the ambient thus helping to prevent Covid-19.

  3. Ventilation is a very important control measure for covid-19. One effective measure is CO2 concentration. Outdoor air has a CO2 concentration of about 410ppm. Below 800ppm is well ventilated, above is cause for concern. Above 1500 means you should get out. (source: Paywall Warning:
    Definitely an interesting range of sensors for a personal portable CO2 monitoring solution.

  4. This whole CO2 is bad for you thing is hypochondria, you will feel your breathing rate rise long before CO2 levels are dangerous and even with enough oxygen that will happen because your body can’t sense it. You have an exquisitely fine tuned CO2 detector built from to your biochemistry. Carbon monoxide and sulphur compounds etc are real toxins that you need to detect externally.

    1. I just realized this was about CO2, and not carbon monoxide.

      It was the latter that almost killed Richard Byrd the winter he spent alone in a hutin a hole in Antarctica.

    2. I was in a walk-in cooler that had a CO2 leak from the fountain soda pump. I felt out of breath and queasy, and thankfully didn’t get trapped in the blanket near the floor. Had no idea it was CO2 though until later when we found out the tank was empty.

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