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A small Monitor that displays the progression of the CO2-concentration within one day.

If you stay in a room or simply if you light a candle, the CO2 concentration will rise as the air quality decreases. There are a lot of air quality monitors giving a number of even a signal indicating that it is time for ventilation. This monitor shows the CO2 protocol of the last 24 hours to see all effects that influence the air quality.

So you can e.g. observe the totally different effects of ventilation at windless or breezy days.

This CO2 monitor gives you a survey over the CO2 contentration over one day. With its NIR CO2 sensor it is extremely sensitive to ventilation or just opening the door of the bedroom in the morning.

For evaluation purpose the monitor can record the CO2 data for about 5 days and replay them to the COM-interface of the arduino nano.

As the CO2 sensor needs some 100 mA when it is in action, the monitor cannot be powered by the arduino directly but can be powered by either a typical 5 V USB power supply/power bank or a generic 7 V - 12 V power supply.


- sensitivity range from 330 to 3000 ppm CO2
- real time clock
- resolution 4 data points per hour
- ppm-axis is scaled automatically
- switch for LCD backlight on/off
- data recording over 4 days
- analog output signal (1000 mV = 1000 ppm) for demonstration purposes
- easy calbration
- stabilized 5 V or unstabilized 7V - 12V power input supported
With two buttons some standard functions can be accessed as:

- data output to COM interface
- set time and date
- calibrate the NIR CO2 sensor to standard air quality”

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