Monitoring the Indoor CO2 Levels is a growing trend. Recent researches suggest that this may even be linked to our decision making skills. Just google "Indoor CO2 Levels" and there are various articles.
This project is about building an affordable CO2 Monitor.
Some time ago, while sitting in a crowded meeting room I started wondering if it would be worth measuring the Oxygen levels in the rooms in our company, and let the occupants know if it drops significantly due to the closed doors and many people.
After reading some articles i actually learned that it is not the Oxygen Level that is the problem, but it is rather the increased level of CO2. The reason is, that the O2 concentration in the air is between 21% (sea level) and 17%(2000m), and we do equally good on both places. While the CO2 level is usually below 0.05% outside, 0.1% inside, and 0.5% is the official limit for 8h occupation in a room. So our bodies are very sensitive to increased CO2.
Then i found a study published few years ago, that suggests that even levels of CO2 around 0.2% actually impact our decision making skills or result in bad sleep. The first being spot-on the problem i had at work, and the latter a bonus feature for at home.
Further reading linked the amount of fresh air in a room to the CO2 Levels, and the fact that measuring the CO2 Level is an easy indicator to show that the windows should be opened. A bad ventilated room potentially contains more dust and germs in the air that would impact our health.
So far so good, i decided to acquire a device to measure this, yet I was shocked by the price tag. Most devices cost 100-150 eur, some even more. Given the fact that I was not sure whether i really need this it was a bit hard to swallow.
Finally a bought just a precise sensor for 100$ and built an Arduino based device to measure if the levels rise so much indeed.
It turned out that just 2 hours after sitting in my room at work (with 4 more colleagues), the CO2 levels rise above 2000 ppm (0.2%), which is already in the red zone for productiveness.
the same situation i saw also in our meeting rooms.
Yet what i saw is that people are not really interested in the raw numbers (400, 1000, 1600 or whatever), they want to know if it is good or bad.
Simple CO2 Monitor
This is how i came to the idea to build a very simple CO2 Monitor, that simply lights several leds to make the situation visible. For this also much cheaper sensors could be used, that may not be that accurate, but still do the job well.
in addition WiFi connectivity may be added, for those of you who would like like to use data logging functionalities.
Currently i am evaluating how precise the cheaper sensors are, and the results are quite good. The next steps are to design some kind of enclosure, and manufacture the device.
The enclosure will be 3D printed. It may not look as good as a real injection molded case, but the entry price for those is too high, and for low volumes it is not reasonable
I am offering the first devices at a discount, and in return i hope that i could discuss the design and features with similar minded people, so that the final device is suitable for the most users
Risks and challenges
1. Risk - CO2 Sensors are not accurate enough
I am evaluating some samples of those sensors since a month and up to now they are quite consistent
2. Challenge - Make a nice 3D Printed Box
3D Printing has it's challenges and I want to make the best of it so that the boxes i create look as professional as possible
- (30 days)